Showing papers in "Energy & Fuels in 2023"
22 citations
TL;DR: In this article , the photovoltaic (PV) performance enhancement of Cs2BiAgI6 double perovskite solar cells (PSCs) by optimizing the optoelectronic parameters of the absorber, electron transport layer, hole transport layer (HTL), and various interface layers was investigated.
Abstract: Lead-free Cs2BiAgI6 has garnered a lot of research interest recently due to its suitability as a potential absorber layer in the solar cell (SC) architecture owing to its low cost, good stability, and high efficiency. The main highlight of this research work includes the photovoltaic (PV) performance enhancement of Cs2BiAgI6 double perovskite solar cells (PSCs) by optimizing the optoelectronic parameters of the absorber, electron transport layer (ETL), hole transport layer (HTL), and various interface layers. Solar Cell Capacitance Simulator One dimension (SCAPS-1D) numerical simulation was used to optimize the performance of Cs2BiAgI6 absorber-based SCs consisting of copper barium thiostannate (CBTS) as the HTL and TiO2, PCBM, ZnO, IGZO, SnO2, and WS2 as ETLs. The role of the non-lead cesium-based halide perovskite absorber layer in the improvement of the SC performance was systematically investigated through a variation in the thickness, doping density, and defect density of the absorber layer, ETL, and HTL. The performance of the investigated device architectures is largely dependent on the thickness of the absorber layer, acceptor density, defect density, and the combination of different ETLs and HTLs. We found that TiO2, PCBM, ZnO, IGZO, SnO2, and WS2 ETL-based optimized devices recorded a power conversion efficiency (PCE) of 23.14, 23.71, 23.69, 22.97, 23.61, and 21.72%, respectively. Furthermore, the effect of series and shunt resistances, temperature, capacitance, and Mott–Schottky for the six optimized devices was estimated along with the computation of the corresponding generation and recombination rates, current density–voltage (J–V), and quantum efficiency (QE) characteristics. The PV parameters obtained from this comprehensive analysis are finally compared with the earlier published theoretical and experimental reports on Cs2BiAgI6 absorber-based SCs.
17 citations
TL;DR: In this paper , a CO2-CH4 displacement model that can provide a continuous pressure gradient in the displacement direction and a stable back-pressure at the pore outlet was developed based on a heterogeneous surface pore.
Abstract: Studying the CO2–CH4 displacement process is of great importance to understand the CO2-enhanced shale gas recovery technology. However, most studies have focused on the gas behavior in the reservoir during the dominant stage of competitive adsorption after CO2 injection, as well as the shale gas recovery, displacement efficiency, and gas separation after displacement, while less attention has been paid to the gas behavior during the initial period of displacement. A CO2–CH4 displacement model that can provide a continuous pressure gradient in the displacement direction and a stable back-pressure at the pore outlet was developed based on a heterogeneous surface pore. The model was divided into three areas: CO2 injection area, pore area, and back-pressure area. Molecular dynamics simulations were used to study the effects of depressurization exploitation and injection pressure on the displacement behavior at the initial period of the displacement process under different reservoir conditions. It was found that the displacement process always starts from the CH4 reverse flow stage and then experiences the injection pressure action stage and positive displacement stage in sequence. Moreover, the extent of CH4 reverse flow directly affects the system development process and the final displacement efficiency. A small system presorption pressure and a large injection pressure are beneficial to the displacement. It is believed that the reservoir pressure should be dropped to the lowest possible level during depressurization exploitation, and the CO2 injection pressure needs to be selected by considering displacement efficiency, reservoir safety, and economic cost. The CO2 occupies the adsorption sites near graphene faster than that near montmorillonite (MMT) in the direction of displacement, while the CH4 desorption is faster near MMT. Therefore, it cannot be concluded that the displacement process near graphene is ahead of MMT. It is considered that the gas desorption/adsorption behavior near the graphene dominates the displacement process in terms of gas amount, while the fluctuation near MMT with time and injection pressure directly affects the gas adsorption variation in the pore space from the trend.
15 citations
TL;DR: In this article , the progress made in the synthesis of metal and metal oxide nanostructures, followed by a discussion regarding the advances in the application of these nano-structures as photocatalysts, electro-catalysts and photo-electrocatalyst.
Abstract: The exponential population growth on earth has put an enormous strain on energy resources, which come in various forms like fossil fuels, geothermal energy, and so on. Currently, fossil fuels are fulfilling most of our energy requirements. However, their nonrenewable nature and the production of toxic and greenhouse gases have forced the research community to explore different renewable and nontoxic energy resources. Among different renewable energy resources, hydrogen is considered an important alternative energy source. However, the production of hydrogen (H2) from water is a nonspontaneous process. Therefore, different processes like photocatalysis and photoelectrocatalysis are employed to carry out the water splitting. For these processes, there is a dire need to develop different substances that can act as catalysts. For energy applications, different metals (particularly noble metals) and metal oxides (mostly transition metal oxides) have shown promising catalytic applications in the past decade. Herein, we discuss the progress made in the synthesis of metal and metal oxide nanostructures, followed by a discussion regarding the advances made in the application of these nanostructures as photocatalysts, electrocatalysts, and photoelectrocatalysts. From an energy application standpoint, it is found that doping and heterostructure development are the most advantageous methods used to date to improve the efficiency of metal and metal oxide nanostructures. Also, the development of dye-sensitized metal oxide catalysts for energy applications is considered a powerful method to develop highly efficient photocatalysts and electro-/photoelectrocatalysts. Finally, the limitations and challenges facing the practical application of these nanostructures are also discussed.
9 citations
TL;DR: In this paper , the state-of-the-art of carbonate-based thermochemical energy storage (TCS) in concentrating solar power (CSP) plants is reviewed.
Abstract: Thermochemical energy storage (TCS) systems are receiving increasing research interest as a potential alternative to molten salts in concentrating solar power (CSP) plants. In this framework, alkaline-earth metal carbonates are very promising candidates since they can rely on wide availability, low cost, high volumetric density (>1 GJ m–3), relatively high operating temperatures (>800 °C), nontoxic and noncorrosive chemical nature, and no occurrence of any side reactions involving the production of undesired byproducts. Therefore, their reversible calcination/carbonation reaction with CO2 can be used to store/release energy in CSP plants. However, in spite of these promising features, the TCS research field is relatively new, and most of it is still limited to the lab-scale. Therefore, great research efforts are needed to bridge the gap from fundamental research to real-scale application and implementation of TCS-CSP systems. This manuscript reviews the state-of-the-art of carbonate-based systems for TCS in CSP plants. In particular, the literature has been analyzed in-depth, paying attention to (i) the materials development, with a focus on the solutions available to improve the durability of the materials (namely, the ability to withstand repeated carbonation/calcination cycles); and (ii) the design of the reactor configuration for both the solar-driven endothermic calcination and the exothermic carbonation reaction, focusing on the optimization of the reactor concept, based on the physicochemical properties and working temperatures of the reagents.
8 citations
TL;DR: In this article , the irreducible water saturation was investigated, and its controlling factors were clarified, and the authors target the Upper Paleozoic Taiyuan and Shihezi Formations, which belong to a tight gas reservoir in the eastern Ordos Basin.
Abstract: After flowback, the residual fracturing fluid will reduce the gas seepage space and influence natural gas production, which attracts widespread attention. In this study, the irreducible water saturation was investigated, and its controlling factors were clarified. We target the Upper Paleozoic Taiyuan and Shihezi Formations, which belong to a tight gas reservoir in the eastern Ordos Basin. The main experiments include porosity, permeability, mineral composition, nitrogen adsorption, mercury intrusion porosimetry, nuclear magnetic resonance, and high-speed centrifugation. The specific surface area is very low and varies from 0.95 to 4.03 m2/g, and the median pore-throat diameter ranges from 28.6 to 698.6 nm. Through the T2 cutoff value, the water saturation can be divided into movable water saturation (Smov) and irreducible water saturation (Sirr). Furthermore, the Sirr can be divided into water saturation in large pores controlled by the small throat (Sirrl) and water saturation controlled by the capillary force (Sirrc). In both formations, the Sirr has a negative relationship with porosity, permeability, and average pore diameter and exhibits a positive relationship with the specific surface area. The Sirrl has a positive relationship with the median pore-throat diameter in Taiyuan Formation, but the Sirrl has a weak relationship with the median pore-throat diameter in Shihezi Formation. The Sirrc has a negative relationship with porosity, permeability, and average pore diameter and displays a positive relationship with the specific surface area in Taiyuan Formation, but the Sirrc has a weak relationship with these parameters in Shihezi Formation. The relationship difference between Taiyuan and Shihezi Formations was mainly caused by the pore structure, demonstrated by the amplitude ratio in three peaks. Based on the above analysis, this study is conducive to understanding the mechanism of water occurrence and its controlling factors.
8 citations
TL;DR: In this paper , density functional theory (DFT) and SCAPS-1D-based studies were reported to evaluate the photovoltaic (PV) performance of CsPbBr3-based PSCs.
Abstract: The power conversion efficiency (PCE) of cesium lead halide (CsPbX3, X = l, Br, and Cl)-based all-inorganic perovskite solar cells (PSCs) is still struggling to compete with conventional organic–inorganic halide perovskites. A combined material and device-related analysis is much needed to understand the working principle to explore the efficiency potential of CsPbX3-based PSCs. Therefore, here, density functional theory (DFT) and SCAPS-1D-based studies were reported to evaluate the photovoltaic (PV) performance of CsPbBr3-based PSCs. DFT is first applied to assess and extract structural and optoelectronic properties (band structure, density of states, Fermi surface, and absorption coefficient) of the considered absorber layer. The calculated electronic band gap (Eg) of the CsPbBr3 absorber was 1.793 eV, which matched well with the earlier computed theoretical value. Additionally, the Pb 6p orbital contributed largely to the calculated density of states (DOS), and the electronic charge density map showed that the Pb atom acquired the majority of charges. In order to examine the optical response of CsPbBr3, optical characteristics were computed and correlated with electronic properties for its probable photovoltaic applications. Fermi surface computation showed multiband characters. Furthermore, to look for a suitable combination of the charge transport layer, a total of nine HTLs (Cu2O, CuSCN, P3HT, PEDOT:PSS, Spiro-MeOTAD, CuI, V2O5, CBTS, and CFTS) and six ETLs (TiO2, PCBM, ZnO, C60, IGZO, and WS2) are used considering the experimental Eg (2.3 eV). The best power conversion efficiency (PCE) of 13.86% is reported for TiO2 and CFTS in combination with the CsPbBr3 absorber. The effects of operating temperature, series and shunt resistances, Mott–Schottky, capacitance, generation and recombination rates, quantum efficiency, and current–voltage density were also examined. The resulting PV properties were also compared with previously published data. Results reported in this study will pave the way for the development of high-efficiency all-inorganic CsPbBr3-based solar cells in the future.
6 citations
TL;DR: In this article , a review of recent advances in the biomass porous carbon synthesis process focusing on different carbonization and activation strategies, point out the scope of applicability and advantages/disadvantages of these methods in supercapacitor applications, and reveal the reaction mechanisms and limitations for commercial production.
Abstract: In the past decades, fossil energy depletion, environmental pollution, and greenhouse gas emissions have resulted in serious health threats and ecological imbalances, which prompt researchers to explore green and sustainable supercapacitor energy storage and conversion systems. Biomass is a promising renewable energy source to use for biomass porous carbon for supercapacitor devices because it is renewable and has abundant reserves, a low price, and low pollution carbon energy. To date, although some reports have screened different biomass precursors, carbonization methods, and activation strategies and mechanisms, a comprehensive evaluation and critical review of the correlation among biomass porous carbon properties, including pore structure and surface chemistry, and electrochemical energy storage performances of supercapacitors are absent from a multidisciplinary assessment perspective. Therefore, in this review, we summarize recent advances in the biomass porous carbon synthesis process focusing on different carbonization and activation strategies, point out the scope of applicability and advantages/disadvantages of these methods in supercapacitor applications, and reveal the reaction mechanisms and limitations for commercial production. Then, the relationships among biomass porous carbon properties, including hierarchical porous structure, surface chemistry, specific surface area, and electrochemical performances of supercapacitors are reviewed in detail, which enables researchers to prepare and design advanced materials in a more rational way and facilitates them to explore more cutting-edge energy storage materials. Finally, two effective techniques including heteroatom doping and composite material construction are reviewed to address the general problem of low supercapacitor energy density. This review demonstrates the great potential of biomass porous carbon with superior properties, provides advanced tailoring and design viewpoints for the application fields of high-performance supercapacitors, and is expected to inspire new exploration and boost the practical commercial applications of biomass-derived hierarchical porous carbon material in more energy storage and conversion fields.
6 citations
TL;DR: In this paper , the authors highlight the progress of CO2-enhanced coalbed methane recovery (CO2-ECBM) under laboratory conditions, e.g., the binary gas competitive adsorption and gas displacement experiments in the macroscale and porous structure tests using technologies of nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), and computed tomography (CT) in the microscale.
Abstract: Carbon dioxide (CO2)-enhanced coalbed methane recovery (CO2-ECBM) is a critical way to increase methane production and reduce greenhouse gas (CO2 and CH4) emissions. As captured CO2 is continuously injected in the coal seams, a low cost of CO2 sequestration and high efficiency of CH4 recovery can be achieved via the flooding and replacing effects driven by the injected CO2 flow. Scientific insights into the complex process of CO2-ECBM in experiments, modelings, and technological developments need to be made to propose appropriate countermeasures. This review first highlights the progress of CO2-ECBM under laboratory conditions, e.g., the binary gas competitive adsorption and gas displacement experiments in the macroscale and porous structure tests using technologies of nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), and computed tomography (CT) in the microscale. Then, the advances of mathematical models for changing in coal permeability and porosity during CO2-ECBM are reviewed, accompanying with the multi-field and multi-phase coupling responses of competitive sorption, diffusion, gas–water seepage, heat transfer, and solid deformation. Furthermore, the field pilot tests of CO2-ECBM in various countries and regions are also covered to reveal the key technical challenges confronted with the development of CO2-ECBM technology. The perspectives in experiments, models, and field pilots of CO2-ECBM are made, which include but are not limited to the following: conducting a core CH4/CO2 flooding test under in situ conditions, modeling CO2-ECBM with real fractures/faults and coal failure, developing a new method for gas migration and leakage monitoring in the field, and enacting relevant standards, laws, and regulations to promote CO2-ECBM.
5 citations
TL;DR: The main objective of as discussed by the authors is to assess the advances made in CO2 storage projects globally and present the alternative for the sequestration of CO2 into the geological formations through existing major projects.
Abstract: Carbon capture and storage (CCS) is a climate change mitigation method in which anthropogenic carbon dioxide (CO2) is captured from large point sources and stored in geological formations, in the ocean, or through mineral carbonation. CO2 can be injected and stored for a variety of reasons, including permanent disposal or enhanced oil recovery in certain oil fields. The main objective of this paper is to assess the advances made in CO2 storage projects globally. This study reviews the major companies/businesses that are involved in CCS deployment. The study also presents the alternative for the sequestration of CO2 into the geological formations through existing major projects. It explains their progress, structural and faulting configuration, CO2 transportation and injection, potential CO2 source(s), estimation of the storage capacity, etc. This study also highlights the monitoring programs that are used in different operating projects and the status of active projects. The study suggests that CCS faces further deployment challenges due to the heterogeneity and complexity of rock formations, high cost of deployment, possibility of formation damage during injection and potential for migration and leakage of CO2. Additionally, inappropriate strategy for CO2 injection may lead to wellbore integrity problems, formation of hydrates, and inadequate pressure control. More research─particularly, geological evaluation before injection and storage─is apparently needed.
5 citations
TL;DR: In this paper , the potential of Ga12As12 as a hydrogen adsorbent and storage material was investigated within the framework of density functional theory (GGA-DFT) computations at the B3LYP-GD3BJ/def2tzvp level of theory.
Abstract: While hydrogen combustion generates a lot of energy and can be done in a variety of ways, the primary challenge in utilizing hydrogen energy is obtaining an efficient hydrogen storage material. Herein, the potential of Ga12As12 as a hydrogen adsorbent and storage material was investigated within the framework of density functional theory (GGA-DFT) computations at the B3LYP-GD3BJ/def2tzvp level of theory. The study was systematically conducted by increasing the number of molecular hydrogen adsorptions (n = 1–4) at Ga- and As- sites of the Ga12As12 adsorbent material. Results showed that adsorption on the As site is preferred as the hydrogen binding on this site is closer to the DoE requirement. Via DFT-GGA with the incorporation of D3 dispersion, we demonstrated that the Ga12As12 nanocluster can store up to four molecular hydrogens with a calculated gravimetric wt % of 5.71%, closer to the 6.5 wt % proposed by the DoE. Average binding energies for both As and Ga adsorption sites were observed to be −0.49 and −0.84 eV, respectively, which is within the range of H2 adsorption energy according to DoE. The electronic properties, thermodynamics, and the density of state disclosed a linear relationship with the increase in H2 adsorption. This trend is also seen in the adsorption energy, which shows a higher adsorption range as the number of hydrogen molecules on the Ga12As12 nanocage increases. Ab initio molecular dynamics simulations divulged that the studied system is considerably stable both at room temperature and at extreme temperatures. Based on the utilization of GGA exchange correlations, confirmation of stability via ab initio MD simulations, high desorption temperature (1454 K), and the computed gravimetric wt % (5.71), which is close to the DoE standard (6.5%), we strongly believe that proper surface engineering of the studied Ga12As12 nanocluster could further improve the overall properties and suitability toward hydrogen storage applications.
TL;DR: In this paper , a high-pressure isothermal adaption model was used to describe the adsorption behavior of methane in deep shales, and the proportion of adsorbed gas and free gas in deep shale gas reservoirs was characterized quantitatively.
Abstract: The quantitative characterization of adsorbed gas and free gas in shale reservoirs is a key issue in exploration and development of shale gas. Thus, the aforementioned topic is of great significance to the evaluation of reserves, the screening of favorable target areas, and the formulation of development plans. However, research on our current understanding of the quantities of adsorbed gas and free gas in deep shale gas reservoirs is still lacking. To address this problem, deep shales from the Longmaxi Formation in southern China were collected to conduct high-pressure isothermal adsorption experiments. The high-pressure isothermal adsorption model was used to describe the adsorption behavior of methane in deep shales, and the adsorbed gas and free gas in the deep shales were characterized quantitatively. The effects of temperature, pressure, and moisture on the adsorbed gas and the density of the free gas were analyzed. The results indicated that the excess adsorption isotherm curve for methane in deep shales increased and then decreased with the increase of pressure, and the modified Langmuir adsorption model may be used to describe the high-pressure adsorption behaviors. The adsorbed gas in shales decreases gradually with the increase of pressure, and the proportion of adsorbed gas and free gas is between 23 and 74% when the pressure reaches 50 MPa. The adsorbed gas in deep shales decreases with an increase of temperature, and the presence of water greatly reduces the adsorption capacity of the deep shale. The pore space occupied by the free gas in shale increased with the increase in the density of the free phase, and the ratio of the adsorbed gas to the free gas decreased. This research provides a useful reference for explaining how to best evaluate shale gas reservoirs, estimate the reserves in deep shales, and evaluate the adsorption and flow capacity of deep shale gas.
TL;DR: In this article , Li et al. investigated the residual oil distribution in the first and second members of the Upper Cretaceous Qingshankou Formation in the Songliao Basin and found that residual oil has a wide distribution among different pores, ranging from 1 to 200 nm.
Abstract: Rock fabric and its influence on residual oil distribution are key issues to the highly efficient development of shale oil. This study targeted the rock fabric and residual oil distribution, and samples were selected from the first and second members of the Upper Cretaceous Qingshankou Formation in the Songliao Basin. Multiple methods were used to analyze rock fabric, including material composition, scanning electron microscopy (SEM), micro-computed tomography (micro-CT), and low-temperature nitrogen adsorption (LT-NA). The residual oil distribution was investigated by methods of oil extraction and LT-NA. The organic matter of most samples belongs to type I, and clay is the main mineral component, which can be as high as 65.4%. There are a lot of inorganic pores at the nanoscale, while the organic pores mainly range from 10 nm to 2 μm, and at the microscale, the pore connectivity is poor in both formations. The apparent and intrinsic average specific surface areas (SSAs) are 5.35 and 10.23 m2/g, respectively, indicating that the average SSA of post-oil extraction is nearly 2 times that of pre-oil extraction. The residual oil has a wide distribution among different pores, ranging from 1 to 200 nm. In most cases, the residual oil mainly exists in pores between 1 and 5 nm, indicating small pores holding abundant oil. The pore space ratio for residual oil has a negative relationship with clay content, total organic matter (TOC), pyrolysis hydrocarbon (S2), and intrinsic average pore diameter, indicating that higher clay content is detrimental to liquid hydrocarbon generation. Higher TOC and S2 mean less generated liquid hydrocarbon, and a higher intrinsic average pore diameter means fewer nano organic pores for liquid hydrocarbon. This study is conducive to understanding the rock fabric of lacustrine shale and its influence on residual oil distribution.
TL;DR: In this paper , the authors discuss the existing atomistic models of kerogen by categorizing them according to the different approaches and assumptions used during their construction and discuss possible improvements and upscaling strategies to better account for kerogen in its geological environment.
Abstract: With the emergence of shale gas, numerous atomic-scale models of kerogen have been proposed in the literature. These models, which attempt to capture the structure, chemistry, and porosity of kerogens of various types and maturities, are nowadays commonly─if not routinely─used to gain nanoscale insights into the thermodynamics and dynamics of complex and important processes such as hydrocarbon recovery and carbon sequestration. However, modeling such a complex, disordered, and heterogeneous material is a particularly challenging task. It implies that important underlying assumptions and simplifications, which can significantly affect the predicted properties, have to be made when constructing the kerogen models. In this mini review, we discuss the existing atomistic models of kerogen by categorizing them according to the different approaches and assumptions used during their construction. For each type of model, we also describe how the construction strategy can impact the prediction of certain properties. Important work on kerogen interactions with gas and oil, from both the point of view of equilibrium adsorption (including adsorption-induced deformation) and transport, are described. Possible improvements and upscaling strategies─to better account for kerogen in its geological environment─are also discussed.
TL;DR: In this article , the authors used a chemical called ethylenediaminetetraacetic acid (EDTA) chelating agent in a carbonate reservoir to shed light on contact angle differences of 625 aged thin sections.
Abstract: The injection of chemical fluids into oil reservoirs is gaining widespread attention in light of the declining conventional oil resources by recovering more hydrocarbons. This study is focused on using a chemical called ethylenediaminetetraacetic acid (EDTA) chelating agent in a carbonate reservoir to shed light on contact angle differences of 625 aged thin sections and rock dissolution under the influence of different pHs, temperatures, chelating times, and various chelating agent concentrations in seawater. According to a rock dissolution test, at least 5 wt % of EDTA chemical is needed to obtain oil recovery. A ζ potential test and scanning electron microscopy (SEM) images revealed that the mechanism of adsorption at low pH values and the expansion of the electrical double layer (EDL) at high pH values were responsible for wettability alteration, and an increase in EDTA concentration intensified each mechanism. Interfacial tension (IFT) measurements also showed that adding 1 and 10 wt % of the EDTA to the seawater solution reduced the IFT by 67.75% and 76.08%, respectively. The contact angle experiments demonstrated an increase in the mechanism that leads rock to behave more hydrophilically as pH, solution temperature, and chelating agent concentration in saltwater increased. Artificial neural network (ANN) methods also led to the introduction of a model to predict the contact angle employing multilayer perceptron neural networks (MPNN) and cascade feedforward neural networks (CFFNN). The CFFNN with two hidden neurons and trained by the Levenberg–Marquardt backpropagation algorithm is the most accurate model when comparing the accuracy of models for predicting contact angle values. The CFFNN model indicated that the weight percentage of the chelating chemical, which has a share of about 90%, had the greatest influence on the contact angle, and chelating time, with a share of less than 10%, had the least.
TL;DR: In this article , a ternary nanocomposite (PANI/G-LS/WS2-LS) was proposed to improve the performance of PANI. But the performance was not as good as PANI, as compared with WS2.
Abstract: Integrating polyaniline (PANI) with two-dimensional (2D) nanostructures is a promising strategy to improve electrochemical performance. In this work, 2D laminar van der Waals heterostructures of graphene and WS2 nanosheets were prepared for the enhancement of the supercapacitive performance of PANI. With well-dispersed graphene/WS2 nanosheet hybrids (G-LS/WS2-LS) as deposition supports, the in situ polymerization of aniline delivered a ternary nanocomposite PANI/G-LS/WS2-LS. Benefiting from the good electrical conductivity and chemical stability of graphene, as well as the high redox activity of WS2, the ternary nanocomposite (PANI/G-LS/WS2-LS) exhibited significantly enhanced electrochemical performance as compared with PANI. Typically, a high specific capacitance of 421.5 F/g was delivered at a current density of 1 A/g in a three-electrode system, which is more than 1.5 times that of PANI (274.1 F/g at 1 A/g). Additionally, the symmetric supercapacitor based on PANI/G-LS/WS2-LS showed good electrochemical stability with a 71.6% capacitance retention after 10,000 cycles at 5 A/g and a high specific energy of 9.96 W h/kg at a specific power of 250.04 W/kg. The study provides a facile approach to boost the electrochemical performance of conductive polymers for efficient and reliable energy storage.
TL;DR: In this article , a review discusses extensively the exploitation of tunable features of different special structures of carbons derived from components of lignin, cellulose and lignocellulose, and their transformations as electrode materials for supercapacitors and battery applications.
Abstract: Advancements to tackle the 21st-century energy crisis are being made focusing majorly on sustainability. Lignin and cellulose comprise major parts of biomass and have plenty of advantages such as abundance, eco-friendliness, cost effectiveness, sustainability, and renewability. Utilizing them as precursors for electrode materials for supercapacitors and batteries is promising. The present review discusses extensively the exploitation of tunable features of different special structures of carbons derived from components of lignin, cellulose, and lignocellulose, and their transformations as electrode materials for supercapacitors and battery applications. The structures have been categorized into carbon nanosheets, carbon nanofibers, hierarchically porous carbon, and heteroatom-doped carbon. Their performance studies with various electrochemical optimizations for energy storage have been discussed comprehensively with a significant emphasis on the structural morphologies of the discussed materials. As the materials also have some limitations, the review highlights a few gaps and challenges to be encountered for further developments with a future perspective in energy storage.
TL;DR: In this paper , the effect of sample composition, i.e., 5% NO@MX, 10% NO, 15% NO and 20% NO on the performance of a supercapacitor was investigated.
Abstract: MXene composites with different metal oxides have recently demonstrated good electrochemical performance with enhanced conductivity and also hinder the restacking of MXene. With this motivation, we synthesized the nickel oxide@MXene (NO@MXene) series with varying compositions, which was screen-printed on a flexible stainless-steel mesh (FSSM) substrate as an anode for a supercapacitor. The effect of sample composition, i.e., 5% NO@MX, 10% NO@MX, 15% NO@MX, and 20% NO@MX, on the electrochemical properties is studied systematically. The 15% NO@MX composite electrode demonstrated a maximum capacitance of 1542 F g–1@6 mA cm–2 current density in 1 M KOH. An all-solid-state asymmetric supercapacitor (ASC) with 15% NO@MX (anode) and copper oxide (cathode) displayed a 1 V potential window. The device exhibited a specific capacitance of 73.3 F g–1@10 mA cm–2 current density with a maximum energy density of 10.7 Wh kg–1 and a power density of 3333 W kg–1 in polymer gel of PVA–KOH electrolyte. The cyclic stability of the device demonstrates 90.6% capacitance retention over 5000 cycles. It is envisaged that 15% NO@MX as an anode would serve as a promising electrode for the all-solid-state device for supercapacitor applications.
TL;DR: In this article , a pilot-scale distillation plant has been designed, erected, and operated using TPO derived from an industrial-scale pyrolysis plant, which consists of a packed column (20 kg/h) and is within the fifth technological readiness level.
Abstract: Tire pyrolysis oil (TPO) is one of the most interesting products derived from the pyrolysis of end-of-life tires. Among others, it contains valuable chemicals, such as benzene, toluene, ethylbenzene, and xylene (BTEX), as well as limonene. In order to recover these chemicals, a pilot-scale distillation plant has been designed, erected, and operated using TPO derived from an industrial-scale pyrolysis plant. The distillation facility consists of a packed column (20 kg/h) and is within the fifth technological readiness level. This work describes for the first time the fractioning of the TPO in a continuous operational mode under industrially relevant conditions. For this purpose, different reboiler temperatures (250–290 °C) and reflux ratios (up to 2.4) were preliminarily assessed on the yields and properties of the resulting products: light fraction (LF) and heavy fraction (HF). Thus, the distillation plant is capable of producing 27.0–36.7 and 63.3–73.0 wt % of LF and HF, respectively. The highest BTEX concentration in the LF (55.2 wt %) was found using a reboiler temperature of 250 °C and a reflux ratio of 2.4. Contrarily, the highest limonene concentration (4.9 wt %) in the LF was obtained at 290 °C in the reboiler without reflux. In this sense, the lower the reboiler temperature, the higher the BTEX, and the lower the limonene concentration in the LF. The main results herein obtained serve to gain key insights to operate packed distillation columns using complex and promising hydrocarbons as TPO in order to recover valuable products. In addition, this work provides significant information for optimizing the recovery efficiencies of both BTEX and limonene, as well as their potential applications including that for the resulting HF.
TL;DR: In this paper , a mesoporous Ni/ZSM-5 catalyst was used for anisole conversion in a high-pressure batch reactor, achieving a state-of-the-art performance.
Abstract: The realization of biofuels and chemicals requires the development of highly active and selective catalysts, which are resistant to deactivation. A conventional ZSM-5 (SiO2/Al2O3 = 30) was modified with 0.2 M NaOH to generate a mesoporous zeolite support. The parent zeolite, mic-ZSM-5, the modified zeolite, hie-ZSM-5, and a mesoporous silica support, SiO2, were impregnated with 5% nickel and characterized using X-ray powder diffraction (XRD), Brunauer–Emmett–Teller (BET) analysis of nitrogen sorption, scanning electron microscopy with energy dispersive X-ray (SEM-EDX), transmission electron microscopy (TEM), hydrogen temperature-programmed reduction (H2-TPR), ammonium hydrogen temperature-programmed desorption (NH3-TPD), and thermogravimetric analysis (TGA). The influences of the support properties and solvent during the hydrodeoxygenation of anisole were investigated by measuring concentration profiles and rates in a high-pressure batch reactor. NaOH treatment significantly improved the pore structure, acidity of the support, and metal dispersion as well as the interaction of nonframework Ni species with zeolite and, hence, the catalytic activity and selectivity. The highest anisole conversion of 100% was obtained in 120 min over the hie-Ni/ZSM-5 catalyst with cyclohexane selectivity of 88.1%. In addition, the Ni/SiO2 catalyst was 84.5% selective to toluene at 48.9% anisole conversion in 120 min; as such, it was proposed that the transformation of anisole proceeds via either a direct deoxygenation–hydrogenation or isomerization–direct deoxygenation pathway. However, no substantial differences in anisole conversion or product selectivity were observed when decalin and n-decane were compared as solvents. A catalyst reusability test showed hie-Ni/ZSM-5 as the most stable of the three catalysts in terms of anisole transformation, even though the catalyst recorded the biggest weight loss of 9.2% suggesting high resistance to carbon deactivation. Therefore, with this very good catalytic activity, good selectivity to liquid product, and stability, the mesoporous Ni/ZSM-5 catalyst is a potential candidate for economically beneficial future industrial applications.
TL;DR: In this paper , a number of novel MOF-on-MOF composites possessing UiO-66 topologies, namely, Uo-66(Ce), UoMo-Zr)-NH2@Uo-Ce photocatalyst, were prepared, and their photocatalytic activity was examined in the overall water splitting under simulated sunlight irradiation.
Abstract: There is a large interest in the sustainable conversion of H2O into H2 and O2, assisted by sunlight. In recent times, metal–organic frameworks (MOFs) have evolved as promising photocatalysts for this reaction. In the present study, a number of novel MOF-on-MOF composites possessing UiO-66 topologies, namely UiO-66(Ce), UiO-66(Zr)-NH2, UiO-66(Zr)-NH2@UiO-66(Ce), and UiO-66(Ce)@UiO-66(Zr)-NH2, are prepared, and their photocatalytic activity is examined in the overall water splitting under simulated sunlight irradiation. Among these photocatalysts, promising activity is observed with the UiO-66(Zr)-NH2@UiO-66(Ce) photocatalyst, exhibiting 708 and 320 μmol g–1 at 22 h for H2 and O2, respectively. This enhanced photocatalytic activity of UiO-66(Zr)-NH2@UiO-66(Ce) is associated with its adequate energy band diagram and ability for photoinduced charge separation, as revealed by several spectroscopic measurements, such as photoluminescence and transient absorption spectroscopy together with specific photocatalytic measurements. This study is an illustrative investigation showing the photocatalytic activity of MOF-on-MOF composites for the overall water splitting under simulated sunlight irradiation.
TL;DR: The potential of Cs3Bi2I9 perovskite as an absorber layer for solar cells (SCs) was first analyzed by performing density functional theory (DFT) calculations to observe its structural, optical, and electronic properties as mentioned in this paper .
Abstract: Cs3Bi2I9 as a solar absorber material is a strong contender for lead-free perovskite solar cells (PSCs). The presence of bismuth (Bi) in Cs3Bi2I9 leads to the origin of interesting optoelectronic properties along with a suitable optical band gap and high absorption coefficient. However, further analysis of the crystal structure, optical, and electronic properties of this material is required for efficient photovoltaic (PV) applications. The potential of Cs3Bi2I9 perovskite as an absorber layer for solar cells (SCs) was first analyzed by performing density functional theory (DFT) calculations to observe its structural, optical, and electronic properties. Band structure reveals an indirect band gap (2.42 eV), and density of states (DOS) data show good conductivity primarily contributed by the 5p and 6s orbital electrons of I and Bi atoms. Strong electronic charge buildup is seen in the electronic charge density map surrounding the I atom, as well as the covalent bonds between the I and Bi atoms. The frequency-dependent dielectric function and absorption calculations reveal that Cs3Bi2I9 might be a potential material in optoelectronic and photovoltaic systems. We also performed numerical simulations using the one-dimensional solar cell capacitance simulator (SCAPS-1D) for 49 different PSC configurations with Cs3Bi2I9 absorber, electron transport layers (ETLs) comprising WS2, indium–gallium–zinc oxide (IGZO), SnO2, ZnO, C60, TiO2, and phenyl-C61-butyric acid methyl ester (PCBM), and hole transport layers (HTLs) like Cu2O, CuSCN, NiO, poly(3-hexylthiophene) (P3HT), poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), Spiro-MeOTAD, and CuI. Simulation results reveal that the Cu2O HTL exhibited the best power conversion efficiency (PCE) for all of the ETLs. Of the 49 configurations, the six best configurations with the Cu2O HTL and different ETLs were analyzed to study the effect of absorber and ETL thickness, series and shunt resistances, operating temperature, capacitance, Mott–Schottky, generation, and recombination rate on the PV performance. Current–voltage (J–V) characteristics and quantum efficiency (QE) were computed for all of these configurations to understand the impact of the absorber, ETL, and HTL on the PV parameters. This comprehensive simulation study will assist researchers in the fabrication of cheap and efficient PSCs without lead and open new horizons in the field of solar technology.
TL;DR: In this paper , the authors summarized the recent progress for enhancing the catalytic stability of catalysts and tried to obtain an in-depth understanding of the long-term durability, resistance to sinter, and tolerance for multi-impurities.
Abstract: As typical air pollutants, CO, CH4, and volatile organic compounds (VOCs) have received great attention due to their negative impact on the environment and human health. Heterogeneous catalysts are widely used in the catalytic removal of exhaust emission from industrial and automobile sources but still suffer from deactivation because of various factors. The development of a catalyst with excellent catalytic stability is highly desired. We herein summarized the recent progress for enhancing the catalytic stability of catalysts and tried to obtain an in-depth understanding of the long-term durability, resistance to sinter, and tolerance for multi-impurities. Finally, the current challenges and future perspectives for developing stable and highly efficient catalysts in the fields of synergistic catalytic removal of pollutants or resource utilization of VOCs via the selective catalytic oxidation are proposed.
TL;DR: In this article , a flexible and thin ceramic polymer electrolyte membranes combined with the advantage of garnet-structured fast lithium-ion conductors (Li6.28Al0.24La3Zr2O12) with polyvinylidene fluoride polymers was proposed.
Abstract: Solid-state batteries have been getting considerable attention in recent times due to the safety issues associated with liquid electrolyte-based batteries. However, most rigid solid electrolytes are vulnerable to mechanical strains, so implementation in a commercial battery needs proper modifications. Polymer-type flexible membranes could overcome the size and fragility. Herein, we propose a straightforward preparation of flexible and thin ceramic polymer electrolyte membranes combined with the advantage of garnet-structured fast lithium-ion conductors (Li6.28Al0.24La3Zr2O12) with polyvinylidene fluoride polymers. An 8:2 ratio of garnet to polymer has been employed to create a free-standing flexible ceramic polymer electrolyte through tape casting. The membrane showed excellent electrochemical performance with good conductivity and thermal–electrochemical stability. A facile way of polymer electrolyte casting over lithium iron phosphate electrode material, which contains 5 wt % garnet material, has been adapted to enhance the electrode–electrolyte contact. The cell has offered significantly notable performance. This way, the benefit of solid-state electrolytes could extend to the large-scale production of solid-state batteries with extended safety.
TL;DR: In this article , the relative contributions of bromide from coal feedstocks and bromine-based mercury control processes, estimates the distribution of Bromide concentrations at 85 active coal-fired power plants across the United States (U.S.) with wet flue gas desulfurization units, and estimates the cost of removing bromides from wastewater discharge using year 2020 data.
Abstract: Bromide discharges from coal-fired power plants have received increased attention from regulatory bodies due to their contribution to the formation of disinfection byproducts (DBPs) in downstream drinking water treatment plants. This paper characterizes the relative contributions of bromide from coal feedstocks and bromine-based mercury control processes, estimates the distribution of bromide concentrations at 85 active coal-fired power plants across the United States (U.S.) with wet flue gas desulfurization units, and estimates the cost of bromide removal from wastewater discharge using year 2020 data. Bromide discharges are estimated at the plant level using a combination of the reported coal rank and composition combusted, estimates of bromide addition in mercury control techniques under multiple halogen addition scenarios, and the estimated flue gas desulfurization (FGD) wastewater flow rate. The median, simulated plant-level estimation of total FGD wastewater flow is 18.3 gallons/min at a bromide concentration of 319 mg/L, equivalent to ∼11.6 tonnes/year of bromide discharges to the environment. Next, we evaluated the expected cost of employing the best available technology (BAT) to control bromide discharges in FGD wastewater to prevent contributions to DBP formation. Treatment would need to remove more than 99.8% of bromide to reach the 0.2 mg/L voluntary incentive program (VIP) limit. The total cost of treatment depends on whether disposal is on- or off-site; the average costs for all plants combined come to an average of $110 million ($95.2/kgal) in 2021 U.S. dollars for on-site disposal, or $134 million ($115/kgal) for off-site disposal.
TL;DR: In this article , a slow-precipitation-induced material growth approach was used to design a hetero oxide-sulfide material with smaller crystallite size, ultrathin assembled-sheet-like microstructure, and perceptible phase physiognomies (α-MnO2, MnS, and α-NiS).
Abstract: To revolutionize the charge storage efficiency of electrode materials for their utilizations in high Ragone efficient electrochemical energy storage devices, herein, a slow-precipitation-induced material growth approach has been innovated to design a hetero oxide–sulfide [MnO2/NiS–MnS (MnO2/Ni–Mn–S)] material with smaller crystallite size, ultrathin assembled-sheet-like microstructure, and perceptible phase physiognomies (α-MnO2, MnS, and α-NiS). The electroredox assessment of MnO2/Ni–Mn–S illustrates high pseudocapacitive energy storage efficiency, significant redox reversibility, lowly constrained bulk accessibility of the OH– ions at higher rate electrochemical reaction conditions, dominance of semi-infinite diffusion-controlled electrochemical processes, and extremely low charge-transfer resistance (∼1.45 Ω), total series resistance (∼0.51 Ω) and diffusion (Warburg) resistance. A fabricated 1.8 V MnO2/Ni–Mn–S||nitrogen-doped reduced graphene oxide (N-rGO) all-solid-state hybrid supercapacitor (ASSHSC) device with N-rGO as the negative electrode material delivers high area and mass specific capacitance/capacity, ∼100% Columbic efficiency at high-rate operating conditions, and very low charge-transfer and Warburg resistance. The MnO2/Ni–Mn–S||N-rGO ASSHSC device also delivers excellent Ragone efficiency (ED = 31.5 W h kg–1 at PD = 937.5 W kg–1 and ED = 15.5 W h kg–1 at PD = 2767.5 W kg–1) and ∼97.6% retention of charge storage after 11,000 uninterrupted charge–discharge cycles. The significantly improved supercapacitive charge storage efficacy of MnO2/Ni–Mn–S is ascribed to the cohesive redox activity of Ni2+, Ni3+, Mn2+, and Mn3+ and nonstoichiometric Ni2±δ, Ni3±δ, Mn2±δ, and Mn3±δ ions, rich ion-disseminating bulk, S2– vacancy-induced electronic conductivity, and suitable electro-microstructural physiognomies for the electrochemical processes.
TL;DR: In this paper , the authors summarized the recent advances and the strategies of optimizing the electrocatalytic activities of transition metal chalcogenides toward water splitting as well as the latest investigations on the surface reconstructions of TMCs during water electrolysis.
Abstract: Hydrogen is believed to be one of the essential clean secondary energy sources in the energy structure revolution of both industry and daily life. Driven by renewable electricity such as solar and wind power, water electrolysis for hydrogen production is deemed as one of the main processes of green hydrogen production in the future by both academia and industry. Transition metal chalcogenides (TMCs) are promising candidates to replace noble metals as earth-abundant electrocatalysts for water splitting. However, it remains challenging to further improve the electrocatalytic activity and long-term stability of TMCs, especially in a practical water electrolyzer. This Review summarizes the recent advances and the strategies of optimizing the electrocatalytic activities of TMCs toward water splitting as well as the latest investigations on the surface reconstructions of TMCs during water electrolysis. The performances of TMCs in practical electrocatalytic water splitting cells are particularly discussed. Finally, a concluding remark and perspective is provided, and we hope to inspire future works in this area, narrowing the gap between material design and practical application.
TL;DR: In this article , the hollow carbonized cotton cloth (CCC) interlayer was introduced as an interlayer by simple one-step carbonization, enabling LSBs with high rate and cycling performances in all climates.
Abstract: Lithium-sulfur batteries (LSBs) have proven the potential for future power sources due to the ultrahigh theoretical specific capacity, material abundance, and eco-friendliness. However, the insulation of sulfur and the notorious shuttle effect of polysulfides impede the practical use. In this work, we introduced the hollow carbonized cotton cloth (CCC) as an interlayer by simple one-step carbonization. CCC reduces the charge transfer resistance and inhibits the shuttle effect, enabling LSBs with high rate and cycling performances in all climates. Specifically, the LSBs based on the CCC interlayer deliver rate capacities of 118, 399, and 879 mAh g–1 at 2 C at −30, 0, and 50 °C, respectively. Correspondingly in the 1 C cycling tests, the initial specific capacities are 168, 490, and 885 mAh g–1; the decay rates are 0.029% (1000 cycles), 0.034% (1000 cycles), and 0.056% (800 cycles). Moreover, with a higher sulfur loading of 2.3 mg cm–2, the ambient CCC battery achieves a decay rate of only 0.03% per cycle in the 1 C test (800 cycles). Compared with commercial carbon cloth, the ultralow price, light weight, easily scalable preparation, and all-climate good performance of CCC can extremely push LSBs to practical use in the future.
TL;DR: In this article , a modified CCS process based on silica nanoparticle inclusion for shallow coal bed methane (CBM) reservoirs was proposed, and the nanomaterials were evaluated at high pressure in two main stages including CO2 sorption on a single CO2 stream and CO2 selectivity on a flue gas stream.
Abstract: Carbon capture and storage (CCS) is considered a key process to reach net-zero emission by the 2050 aim of limiting global warming. Coal bed methane (CBM) is considered potential geological reservoirs for underground CCS due to the CO2–CH4 exchange feasibility by adsorptive phenomena. Global implementation has been focused only on deep reservoirs to provide methane recovery. Thus, this work proposes a modified CCS process based on silica nanoparticle inclusion for shallow CBM reservoirs (<300 m). The nanomaterials were evaluated at high pressure in two main stages including i) CO2 sorption on a single CO2 stream and ii) CO2 selectivity on a flue gas stream (N2–CO2 mixture). This work includes silica nanomaterial synthesized from rice husk as agro-waste sources with better technical-economic feasibility framed in a circular economy to reduce costs and maximize the use of available resources. Rice husk silica (RSi) nanoparticles were doped with 1.0, 3.0, and 5.0 wt % of urea (Si–U), diethylamine (Si-DE), triethylamine (Si-TE), and ethylenediamine (Si-EM) to enhance the CO2 sorption. First, CO2 sorption was evaluated at 30 °C and between 0.084 and 3 MPa using a CO2 stream to determine the best-doped amount of each N-source. Then, the best nanoparticles were used to impregnate CBM at 10 and 20 wt %, and the subsequent CO2 storage on the flue gas stream (70% v/v N2 and 30% v/v CO2) was done. The results showed that CO2 sorption on RSi increases with the N-group coating in the order RSi-DE < RSi-TE < RSi-U < RSi-EM. Also, the best-doped amount for each N-source was 3 wt %. For CBM impregnation, the nanofluid containing 20 wt % of RSi-EM3 presented the best yield increasing the CO2 sorption from 0.05 to 0.75 mmol g–1, meaning an increase of more than 1000% in the sorption capacity.
TL;DR: In this article , a hollow nanospherical keto-enamine TpPa-1 covalent organic framework (COF) integrated single-atom Co-1T-MoS2 composite with the appropriate band edge potential and an enhanced charge separation was designed to improve its CO2 photoreduction efficiency under visible light irradiation.
Abstract: Photocatalytic conversion of CO2 into beneficial raw chemicals has gained a great deal of attention for well over the recent decade due to its prospect for alleviating energy scarcity and global warming. Even though photocatalytic CO2 reduction technique has shown great promise, the successful conversion of CO2 to the intended outputs has remained a key barrier. Here, we present the design synthesis of a hollow nanospherical keto-enamine TpPa-1 covalent organic framework (COF) integrated single-atom Co-1T-MoS2 (TpPa-1/Co-1T-MoS2) composite with the appropriate band edge potential and an enhanced charge separation to improve its CO2 photoreduction efficiency under visible light irradiation. With a selectivity of 93%, the developed TpPa-1/Co-1T-MoS2 nanocomposite exhibits impressive photocatalytic CO2 reduction efficiency of up to ∼196 μmol g–1 h–1 of CO. Bare TpPa-1 and Co-1T-MoS2 both had around 1.23 and 1.6 times lower CO than TpPa-1/Co-1T-MoS2. Parametric analyses show that the TpPa-1 and Co-1T-MoS2 counterparts have a remarkable cumulative influence on the specificity and efficacy of photoreduction of CO2 to CO. TpPa-1/Co-1T-MoS2 composite is one of the handful of notable values cited in the literature, with an apparent quantum yield of 0.7% at 420 nm under ideal conditions. 13C labeling confirms that the selective conversion of CO2 to CO was facilitated by couplings between TpPa-1 and Co-1T-MoS2, which enhanced charge separation and migration to the surface. The findings show that COFs and their single-atom-based composites can be developed for next-generation photocatalytic systems and that this technology may also be interesting for other energy conversion applications.