Showing papers on "Oxide published in 2022"
TL;DR: In this paper , the three-dimensional graphene oxide (GO) with regular honeycomb structure (GH) is firstly constructed by sacrificial template and freeze-drying methods, then the amino functionalized FeNi alloy particles (f-FeNi) are loaded on the GH skeleton followed by in-situ reduction to prepare rGH@FeNi aerogel.
Abstract: With the rapid development of fifth-generation mobile communication technology and wearable electronic devices, electromagnetic interference and radiation pollution caused by electromagnetic waves have attracted worldwide attention. Therefore, the design and development of highly efficient EMI shielding materials are of great importance. In this work, the three-dimensional graphene oxide (GO) with regular honeycomb structure (GH) is firstly constructed by sacrificial template and freeze-drying methods. Then, the amino functionalized FeNi alloy particles (f-FeNi) are loaded on the GH skeleton followed by in-situ reduction to prepare rGH@FeNi aerogel. Finally, the rGH@FeNi/epoxy EMI shielding composites with regular honeycomb structure is obtained by vacuum-assisted impregnation of epoxy resin. Benefitting from the construction of regular honeycomb structure and electromagnetic synergistic effect, the rGH@FeNi/epoxy composites with a low rGH@FeNi mass fraction of 2.1 wt% (rGH and f-FeNi are 1.2 and 0.9 wt%, respectively) exhibit a high EMI shielding effectiveness (EMI SE) of 46 dB, which is 5.8 times of that (8 dB) for rGO/FeNi/epoxy composites with the same rGO/FeNi mass fraction. At the same time, the rGH@FeNi/epoxy composites also possess excellent thermal stability (heat-resistance index and temperature at the maximum decomposition rate are 179.1 and 389.0 °C respectively) and mechanical properties (storage modulus is 8296.2 MPa).
145 citations
TL;DR: In this article , the three-dimensional graphene oxide (GO) with regular honeycomb structure (GH) is firstly constructed by sacrificial template and freeze-drying methods, then the amino functionalized FeNi alloy particles (f-FeNi) are loaded on the GH skeleton followed by in-situ reduction to prepare rGH@FeNi aerogel.
Abstract: With the rapid development of fifth-generation mobile communication technology and wearable electronic devices, electromagnetic interference and radiation pollution caused by electromagnetic waves have attracted worldwide attention. Therefore, the design and development of highly efficient EMI shielding materials are of great importance. In this work, the three-dimensional graphene oxide (GO) with regular honeycomb structure (GH) is firstly constructed by sacrificial template and freeze-drying methods. Then, the amino functionalized FeNi alloy particles (f-FeNi) are loaded on the GH skeleton followed by in-situ reduction to prepare rGH@FeNi aerogel. Finally, the rGH@FeNi/epoxy EMI shielding composites with regular honeycomb structure is obtained by vacuum-assisted impregnation of epoxy resin. Benefitting from the construction of regular honeycomb structure and electromagnetic synergistic effect, the rGH@FeNi/epoxy composites with a low rGH@FeNi mass fraction of 2.1 wt% (rGH and f-FeNi are 1.2 and 0.9 wt%, respectively) exhibit a high EMI shielding effectiveness (EMI SE) of 46 dB, which is 5.8 times of that (8 dB) for rGO/FeNi/epoxy composites with the same rGO/FeNi mass fraction. At the same time, the rGH@FeNi/epoxy composites also possess excellent thermal stability (heat-resistance index and temperature at the maximum decomposition rate are 179.1 and 389.0 °C respectively) and mechanical properties (storage modulus is 8296.2 MPa).
127 citations
124 citations
TL;DR: In this paper, a new and effective strategy was proposed to develop high efficiency microwave absorbers with ultra-lightweight, wide-band, thin thickness and strong absorption capabilities, benefiting from the excellent synergistic effect between RGOF and reduced graphene oxide foam (RGOF)/MoS2.
119 citations
TL;DR: A comprehensive review about the most recent progress in the synthesis and applications of graphene-based composites is provided in this paper , where the difficulties and challenges in the current development of graphene are summarized and indicated.
Abstract: In the new era of modern flexible and bendable technology, graphene-based materials have attracted great attention. The excellent electrical, mechanical, and optical properties of graphene as well as the ease of functionalization of its derivates have enabled graphene to become an attractive candidate for the construction of flexible devices. This paper provides a comprehensive review about the most recent progress in the synthesis and applications of graphene-based composites. Composite materials based on graphene, graphene oxide (GO), and reduced graphene oxide (rGO), as well as conducting polymers, metal matrices, carbon–carbon matrices, and natural fibers have potential application in energy-harvesting systems, clean-energy storage devices, and wearable and portable electronics owing to their superior mechanical strength, conductivity, and extraordinary thermal stability. Additionally, the difficulties and challenges in the current development of graphene are summarized and indicated. This review provides a comprehensive and useful database for further innovation of graphene-based composite materials.
116 citations
TL;DR: In this paper , the authors used the dry etching process of tantalum (Ta) film to obtain transmon qubits with the best lifetime (T1) for multi-qubit fabrication.
Abstract: By using the dry etching process of tantalum (Ta) film, we had obtained transmon qubit with the best lifetime (T1) 503 us, suggesting that the dry etching process can be adopted in the following multi-qubit fabrication with Ta film. We also compared the relaxation and coherence times of transmons made with different materials (Ta, Nb and Al) with the same design and fabrication processes of Josephson junction, we found that samples prepared with Ta film had the best performance, followed by those with Al film and Nb film. We inferred that the reason for this difference was due to the different loss of oxide materials located at the metal-air interface.
116 citations
TL;DR: In this paper , the authors proposed a new and effective strategy to develop high efficiency microwave absorbers with ultra-lightweight, wide-band, thin thickness and strong absorption capabilities.
113 citations
111 citations
TL;DR: In this paper , a novel enzymatic biosensor based on glutathione peroxidase (GSH-Px), graphene oxide (GO) and nafion for the electrochemical sensing of GSH in body fluids was reported.
108 citations
TL;DR: In this paper, a novel enzymatic biosensor based on glutathione peroxidase (GSH-Px), graphene oxide (GO) and nafion for the electrochemical sensing of GSH in body fluids was reported.
108 citations
TL;DR: In this paper , the electrochemical monitoring of mancozeb through tungsten oxide reduced graphene oxide (WO3/rGO) nanocomposite was described using different analytical tools such as FTIR, XRD and TEM to examine crystallinity, internal texture and the size.
TL;DR: In this paper , a comprehensive overview of the different properties of WO3, including crystallographic, electrical, optical, thermoelectrical, and ferroelectric properties, is provided.
TL;DR: In this article , a facile method is reported to synthesize mesoporous and heterostructured transition metal oxides strongly anchored on a nickel skeleton (MH‐TMO) containing identified Fe-Cu oxide interfaces with high intrinsic activity, easy accessibility for reaction intermediates, and long-term stability for alkaline oxygen/hydrogen evolution reactions.
Abstract: Developing efficient bifunctional electrocatalysts toward oxygen/hydrogen evolution reactions is crucial for electrochemical water splitting toward hydrogen production. The high‐performance electrocatalysts depend on the catalytically active and highly accessible reaction sites and their structural robustness, while the rational design of such electrocatalysts with desired features avoiding tedious manufacture is still challenging. Here, a facile method is reported to synthesize mesoporous and heterostructured transition metal oxides strongly anchored on a nickel skeleton (MH‐TMO) containing identified Fe–Cu oxide interfaces with high intrinsic activity, easy accessibility for reaction intermediates, and long‐term stability for alkaline oxygen/hydrogen evolution reactions. The MH‐TMO with the electrocatalytically active Fe–O–Cu bridge has an optimal oxygen binding energy to facilitate adsorption/desorption of oxygen intermediates for oxygen molecules. Associated with the high mass transport through the nanoporous structure, MH‐TMO exhibits impressive oxygen evolution reaction catalysis, with an extremely low overpotential of around 0.22 V at 10 mA cm−2 and low Tafel slope (44.5 mV dec−1) in 1.0 M KOH, realizing a current density of 100 mA cm−2 with an overpotential as low as 0.26 V. As a result, the alkaline electrolyzer assembled by the bifunctional MH‐TMO catalysts operates with an outstanding overall water‐splitting output (1.49 V@10 mA cm−2), outperforming one assembled with noble‐metal‐based catalysts.
TL;DR: In this article , a series of metal hydroxide-organic frameworks (MHOFs) synthesized by transforming layered hydroxides into two-dimensional sheets crosslinked using aromatic carboxylate linkers is presented.
Abstract: The oxygen evolution reaction is central to making chemicals and energy carriers using electrons. Combining the great tunability of enzymatic systems with known oxide-based catalysts can create breakthrough opportunities to achieve both high activity and stability. Here we report a series of metal hydroxide–organic frameworks (MHOFs) synthesized by transforming layered hydroxides into two-dimensional sheets crosslinked using aromatic carboxylate linkers. MHOFs act as a tunable catalytic platform for the oxygen evolution reaction, where the π–π interactions between adjacent stacked linkers dictate stability, while the nature of transition metals in the hydroxides modulates catalytic activity. Substituting Ni-based MHOFs with acidic cations or electron-withdrawing linkers enhances oxygen evolution reaction activity by over three orders of magnitude per metal site, with Fe substitution achieving a mass activity of 80 A \({\rm{g}}_{\rm{catalyst}}^{-1}\) at 0.3 V overpotential for 20 h. Density functional theory calculations correlate the enhanced oxygen evolution reaction activity with the MHOF-based modulation of Ni redox and the optimized binding of oxygenated intermediates.
TL;DR: In this article , the authors comprehensively review the progresses on the metal support interactions of metal/oxide catalysts and OMI of oxide/metal inverse catalysts with aims to emphasize structure sensitivity of MSI.
Abstract: Solid catalysts usually consist of multicomponents, within which interfacial interactions have been recognized as a key factor affecting structures and catalytic performance. Metal–support interactions (MSI) have been extensively studied in oxide-supported metal catalysts (metal/oxide catalysts), in which the important concepts of strong metal–support interactions (SMSI) and electronic metal–support interactions (EMSI) have been well established and their effects on the metal catalysis have been extensively demonstrated. Recently, metal-supported oxide inverse catalysts (oxide/metal inverse catalysts) have emerged as a new type of efficient catalysts, in which the oxide–metal interactions (OMI) strongly influence the oxide catalysis. Herein we comprehensively review the progresses on the MSI of metal/oxide catalysts and OMI of oxide/metal inverse catalysts with aims to emphasize structure sensitivity of MSI and OMI and to introduce the concepts of electronic oxide–metal interactions (EOMI) and electronic oxide–metal strong interactions (EOMSI) in oxide/metal inverse catalysts, in analogy to the concepts of EMSI and SMSI in metal/oxide catalysts. First, we briefly introduce the background of the topic and the interfacial interactions between metals and oxides with emphasis on the nature of metal–support interfacial interactions depending on the electronic structures. Second, the MSI, with an emphasis on the EMSI and SMSI, in metal/oxide catalysts is reviewed with an emphasis on the recently exported size and facet effects on the electronic structures and MSI. Third, the OMI in oxide/metal inverse catalysts is reviewed with an emphasis on introducing the EOMI and EOMSI. Finally, a summary and outlook is given with emphasis on the local nature and structure sensitivity of MSI and OMI.
TL;DR: In this paper , the authors present recent advances in the fabrication of metal oxide-, 2D nanomaterials-, as well as 2D material/metal oxide composite-based gas sensors with highly sensitive and selective functions.
Abstract: Metal oxide nanoparticles have been widely utilized for the fabrication of functional gas sensors to determine various flammable, explosive, toxic, and harmful gases due to their advantages of low cost, fast response, and high sensitivity. However, metal oxide-based gas sensors reveal the shortcomings of high operating temperature, high power requirement, and low selectivity, which limited their rapid development in the fabrication of high-performance gas sensors. The combination of metal oxides with two-dimensional (2D) nanomaterials to construct a heterostructure can hybridize the advantages of each other and overcome their respective shortcomings, thereby improving the sensing performance of the fabricated gas sensors. In this review, we present recent advances in the fabrication of metal oxide-, 2D nanomaterials-, as well as 2D material/metal oxide composite-based gas sensors with highly sensitive and selective functions. To achieve this aim, we firstly introduce the working principles of various gas sensors, and then discuss the factors that could affect the sensitivity of gas sensors. After that, a lot of cases on the fabrication of gas sensors by using metal oxides, 2D materials, and 2D material/metal oxide composites are demonstrated. Finally, we summarize the current development and discuss potential research directions in this promising topic. We believe in this work is helpful for the readers in multidiscipline research fields like materials science, nanotechnology, chemical engineering, environmental science, and other related aspects.
TL;DR: In this article , the authors used the dry etching process of tantalum (Ta) film to obtain transmon qubits with the best lifetime (T1) for multi-qubit fabrication.
Abstract: By using the dry etching process of tantalum (Ta) film, we had obtained transmon qubit with the best lifetime (T1) 503 us, suggesting that the dry etching process can be adopted in the following multi-qubit fabrication with Ta film. We also compared the relaxation and coherence times of transmons made with different materials (Ta, Nb and Al) with the same design and fabrication processes of Josephson junction, we found that samples prepared with Ta film had the best performance, followed by those with Al film and Nb film. We inferred that the reason for this difference was due to the different loss of oxide materials located at the metal-air interface.
TL;DR: Different perovskite structure-related compounds are discussed in this paper, which could be possible electrode materials in Solid Oxide Fuel Cells (SOFCs) and provide some useful recommendations and prospective directions for designing future electrode materials of SOFCs.
TL;DR: In this article , a defective Co3O4 catalyst was delineated via N doping, leading to a distorted lattice structure, increased active surface oxygen and enhanced oxygen mobility of the catalyst.
TL;DR: In this paper , a strong metal-support interaction (SMSI) state was constructed in a Ru-MoO3 catalyst using CO2 hydrogenation reaction gas and at a low temperature of 250 °C, which favors the selective CO 2 hydrogenation to CO.
Abstract: Encapsulation of metal nanoparticles by support-derived materials known as the classical strong metal-support interaction (SMSI) often happens upon thermal treatment of supported metal catalysts at high temperatures (≥500 °C) and consequently lowers the catalytic performance due to blockage of metal active sites. Here, we show that this SMSI state can be constructed in a Ru-MoO3 catalyst using CO2 hydrogenation reaction gas and at a low temperature of 250 °C, which favors the selective CO2 hydrogenation to CO. During the reaction, Ru nanoparticles facilitate reduction of MoO3 to generate active MoO3-x overlayers with oxygen vacancies, which migrate onto Ru nanoparticles' surface and form the encapsulated structure, that is, Ru@MoO3-x. The formed SMSI state changes 100% CH4 selectivity on fresh Ru particle surfaces to above 99.0% CO selectivity with excellent activity and long-term catalytic stability. The encapsulating oxide layers can be removed via O2 treatment, switching back completely to the methanation. This work suggests that the encapsulation of metal nanocatalysts can be dynamically generated in real reactions, which helps to gain the target products with high activity.
TL;DR: In this paper, a hierarchical composite electrode with 3D hollow and porous carbon nanofibers (3DHPCNF) was used as a free-standing electrode material for supercapacitors and endowed high capacitive behavior at both positive and negative working potentials.
TL;DR: In this article , the authors discussed the preparation, modification, and physical properties of the g-C3N4 and then, they discussed the combination of g-c3n4 with various metal oxides such as TiO2, ZnO, FeO and Fe2O3.
Abstract: g-C3N4 has drawn lots of attention due to its photocatalytic activity, low-cost and facile synthesis, and interesting layered structure. However, to improve some of the properties of g-C3N4, such as photochemical stability, electrical band structure, and to decrease charge recombination rate, and towards effective light-harvesting, g-C3N4–metal oxide-based heterojunctions have been introduced. In this review, we initially discussed the preparation, modification, and physical properties of the g-C3N4 and then, we discussed the combination of g-C3N4 with various metal oxides such as TiO2, ZnO, FeO, Fe2O3, Fe3O4, WO3, SnO, SnO2, etc. We summarized some of their characteristic properties of these heterojunctions, their optical features, photocatalytic performance, and electrical band edge positions. This review covers recent advances, including applications in water splitting, CO2 reduction, and photodegradation of organic pollutants, sensors, bacterial disinfection, and supercapacitors. We show that metal oxides can improve the efficiency of the bare g-C3N4 to make the composites suitable for a wide range of applications. Finally, this review provides some perspectives, limitations, and challenges in investigation of g-C3N4–metal-oxide-based heterojunctions.
TL;DR: In this article, a semi-interpenetrating network of carboxymethyl cellulose (CMC) molecules grafted to polyacrylic acid (PAA) was used as an eco-friendly and non-toxic polymer with numerous carboxyl and hydroxyl functional groups.
TL;DR: In this paper, the molar ratios of Fe3+ to Zn2+ had notable effects on the electromagnetic parameters and microwave attenuation capacity of attained composites, i.e., the obtained composites had the optimal electromagnetic attenuation performance, and the minimum reflection loss achieved −79.0dB with a matching thickness of 2.76mm and effective absorption bandwidth was as high as 5.8GHz under a thin thickness of 1.8mm and low filling ratio of 20.0
Abstract: Developing strong absorption and broadband microwave absorbers derived from metal-organic frameworks (MOFs) still remains a big challenge in the field of microwave absorption. Herein, iron zinc bimetallic metal-organic frameworks/reduced graphene oxide (FeZn-MOFs/RGO) precursors derived ferroferric oxide/carbon (Fe3O4/C) decorated graphene composites were fabricated via a solvothermal and carbonization two-step strategy. It was found that the morphology of carbon frameworks could be regulated from the traditional regular octahedron to the pomegranate shape by simply adjusting the molar ratios of Fe3+ to Zn2+ in the precursors. Moreover, results revealed that the molar ratios of Fe3+ to Zn2+ had notable effects on the electromagnetic parameters and microwave attenuation capacity of attained composites. Significantly, the obtained composites with the molar ratio of Fe3+ to Zn2+ of 1:2 presented the optimal electromagnetic attenuation performance, i.e. the minimum reflection loss achieved −79.0 dB with a matching thickness of 2.76 mm and effective absorption bandwidth was as high as 5.8 GHz under a thin thickness of 1.8 mm and low filling ratio of 20.0 wt%. Additionally, the potential microwave dissipation mechanisms were illuminated. Therefore, our results would shed light on the development of high-efficiency and broadband microwave absorbing composites derived MOFs.
TL;DR: In this article , the molar ratios of Fe 3+ to Zn 2+ had notable effects on the electromagnetic parameters and microwave attenuation capacity of attained composites and the potential microwave dissipation mechanism was proposed.
Abstract: Developing strong absorption and broadband microwave absorbers derived from metal-organic frameworks (MOFs) still remains a big challenge in the field of microwave absorption. Herein, iron zinc bimetallic metal-organic frameworks/reduced graphene oxide (FeZn-MOFs/RGO) precursors derived ferroferric oxide/carbon (Fe 3 O 4 /C) decorated graphene composites were fabricated via a solvothermal and carbonization two-step strategy. It was found that the morphology of carbon frameworks could be regulated from the traditional regular octahedron to the pomegranate shape by simply adjusting the molar ratios of Fe 3+ to Zn 2+ in the precursors. Moreover, results revealed that the molar ratios of Fe 3+ to Zn 2+ had notable effects on the electromagnetic parameters and microwave attenuation capacity of attained composites. Significantly, the obtained composites with the molar ratio of Fe 3+ to Zn 2+ of 1:2 presented the optimal electromagnetic attenuation performance, i.e. the minimum reflection loss achieved −79.0 dB with a matching thickness of 2.76 mm and effective absorption bandwidth was as high as 5.8 GHz under a thin thickness of 1.8 mm and low filling ratio of 20.0 wt%. Additionally, the potential microwave dissipation mechanisms were illuminated. Therefore, our results would shed light on the development of high-efficiency and broadband microwave absorbing composites derived MOFs. • Fe 3 O 4 /C decorated graphene composites derived from bimetallic MOFs were prepared. • Morphology of carbon frameworks evolved from octahedron to pomegranate shape. • Microwave absorption was regulated by adjusting the molar ratios of Fe 3+ to Zn 2+ . • Strong absorption, broad bandwidth, thin thickness and low loading were achieved. • The potential microwave dissipation mechanism of attained composites was proposed.
TL;DR: In this article , a new silver-modified copper-oxide catalyst (dCu2O/Ag2.3) has been proposed for high current operation with partial current density of 326.4 mA cm-2 at -0.87 V vs reversible hydrogen electrode to rank highly significantly amongst reported Cu-based catalysts.
Abstract: Electroreduction of carbon dioxide (CO2) into multicarbon products provides possibility of large-scale chemicals production and is therefore of significant research and commercial interest. However, the production efficiency for ethanol (EtOH), a significant chemical feedstock, is impractically low because of limited selectivity, especially under high current operation. Here we report a new silver-modified copper-oxide catalyst (dCu2O/Ag2.3%) that exhibits a significant Faradaic efficiency of 40.8% and energy efficiency of 22.3% for boosted EtOH production. Importantly, it achieves CO2-to-ethanol conversion under high current operation with partial current density of 326.4 mA cm-2 at -0.87 V vs reversible hydrogen electrode to rank highly significantly amongst reported Cu-based catalysts. Based on in situ spectra studies we show that significantly boosted production results from tailored introduction of Ag to optimize the coordinated number and oxide state of surface Cu sites, in which the *CO adsorption is steered as both atop and bridge configuration to trigger asymmetric C-C coupling for stablization of EtOH intermediates.
TL;DR: In this article, amino grafted magnetic graphene oxide composites using a simple one-step cross-link reaction between the graphene oxide and magnetic Fe3O4/C nanoparticles are presented.
TL;DR: In this article , the defect-driven spontaneous oxidation behavior of MoS2 in an aqueous solution was monitored to optimize the photo-catalytic hydrogen evolution reaction (PHER) performance.
TL;DR: In this paper , the performance and performance of solid oxide fuel cells (SOFCs) operating on hydrogen substitutes are reviewed from the perspective of thermodynamics, kinetics, and structure.