Showing papers by "Nanjing Tech University published in 2020"
887 citations
TL;DR: Inspired by the fiber-reinforced microstructures and mechano-transduction systems of human muscles, a self-healing, long-lasting thermal tolerant and dual-sensory hydrogel-based sensor is proposed, with high gauge factor and a flexible touch keyboard for signature identification and a "fever indicator" for human forehead's temperature detection can be realized by this Hydrogel bioelectronic device.
Abstract: Recently, self-healing hydrogel bioelectronic devices have raised enormous interest for their tissue-like mechanical compliance, desirable biocompatibility, and tunable adhesiveness on bioartificial organs. However, the practical applications of these hydrogel-based sensors are generally limited by their poor fulfillment of stretchability and sensitivity, brittleness under subzero temperature, and single sensory function. Inspired by the fiber-reinforced microstructures and mechano-transduction systems of human muscles, a self-healing (90.8%), long-lasting thermal tolerant and dual-sensory hydrogel-based sensor is proposed, with high gauge factor (18.28) within broad strain range (268.9%), low limit of detection (5% strain), satisfactory thermosensation (-0.016 °C-1), and highly discernible temperature resolution (2.7 °C). Especially by introducing a glycerol/water binary solvent system, desirable subzero-temperature self-healing performance, high water-retaining, and durable adhesion feature can be achieved, resulting from the ice crystallization inhibition and highly dynamic bonding. On account of the advantageous mechanoreception and thermosensitive capacities, a flexible touch keyboard for signature identification and a "fever indicator" for human forehead's temperature detection can be realized by this hydrogel bioelectronic device.
395 citations
TL;DR: This mini-review will focus on the importance of the endocytic pathway as well as the autophagy process in viral infection of several pathogenic CoVs inclusive of SARS- coV, MERS-CoV and the new CoV named as severe acute respiratory syndrome coronavirus 2 (SARS- CoV-2), and discuss the development of therapeutic agents by targeting these processes.
Abstract: Coronaviruses (CoVs) are a group of enveloped, single-stranded positive genomic RNA viruses and some of them are known to cause severe respiratory diseases in human, including Severe Acute Respiratory Syndrome (SARS), Middle East Respiratory Syndrome (MERS) and the ongoing coronavirus disease-19 (COVID-19). One key element in viral infection is the process of viral entry into the host cells. In the last two decades, there is increasing understanding on the importance of the endocytic pathway and the autophagy process in viral entry and replication. As a result, the endocytic pathway including endosome and lysosome has become important targets for development of therapeutic strategies in combating diseases caused by CoVs. In this mini-review, we will focus on the importance of the endocytic pathway as well as the autophagy process in viral infection of several pathogenic CoVs inclusive of SARS-CoV, MERS-CoV and the new CoV named as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and discuss the development of therapeutic agents by targeting these processes. Such knowledge will provide important clues for control of the ongoing epidemic of SARS-CoV-2 infection and treatment of COVID-19.
359 citations
TL;DR: The most recent advances in NPCs for AWE were systematically reviewed, emphasizing the application of in situ/operando experimental methods and density functional theory (DFT) calculations in their understanding and development.
Abstract: Recent years have witnessed an upsurge in the development of non-precious catalysts (NPCs) for alkaline water electrolysis (AWE), especially with the strides made in experimental and computational techniques. In this contribution, the most recent advances in NPCs for AWE were systematically reviewed, emphasizing the application of in situ/operando experimental methods and density functional theory (DFT) calculations in their understanding and development. First, we briefly introduced the fundamentals of the anode and cathode reaction for AWE, i.e., the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER), respectively. Next, the most popular in situ/operando approaches for characterizing AWE catalysts, including hard and soft XAS, ambient-pressure XPS, liquid and identical location TEM, electrochemical mass spectrometry, and Raman spectroscopy were thoroughly summarized. Subsequently, we carefully discussed the principles, computational methods, applications, and combinations of DFT with machine learning for modeling NPCs and predicting the alkaline OER and HER. With the improved understanding of the structure-property-performance relationship of NPCs for AWE, we proceeded to overview their current development, summarising state-of-the-art design strategies to boost their activity. In addition, advances in various extensively investigated NPCs for AWE were evaluated. By conveying these methods, progress, insights, and perspectives, this review will contribute to a better understanding and rational development of non-precious AWE electrocatalysts for hydrogen production.
338 citations
TL;DR: The means by which aligned porous structures and nacre mimetic materials obtainable through recently developed freeze-casting techniques and low-dimensional building blocks can facilitate material functionality across multiple fields of application, including energy storage and conversion, environmental remediation, thermal management, and smart materials, are discussed.
Abstract: Freeze casting, also known as ice templating, is a particularly versatile technique that has been applied extensively for the fabrication of well-controlled biomimetic porous materials based on ceramics, metals, polymers, biomacromolecules, and carbon nanomaterials, endowing them with novel properties and broadening their applicability. The principles of different directional freeze-casting processes are described and the relationships between processing and structure are examined. Recent progress in freeze-casting assisted assembly of low dimensional building blocks, including graphene and carbon nanotubes, into tailored micro- and macrostructures is then summarized. Emerging trends relating to novel materials as building blocks and novel freeze-cast geometries-beads, fibers, films, complex macrostructures, and nacre-mimetic composites-are presented. Thereafter, the means by which aligned porous structures and nacre mimetic materials obtainable through recently developed freeze-casting techniques and low-dimensional building blocks can facilitate material functionality across multiple fields of application, including energy storage and conversion, environmental remediation, thermal management, and smart materials, are discussed.
307 citations
TL;DR: A comprehensive review of recent advances in metal oxide-based electrocatalysts for hydrogen evolution reaction (HER) can be found in this paper, with special emphasis on designed strategies for promoting performance and property-activity correlation.
Abstract: Hydrogen production from electrochemical water splitting represents a highly promising technology for sustainable energy storage, but its widespread implementation heavily relies on the development of high-performance and cost-effective hydrogen evolution reaction (HER) electrocatalysts. Metal oxides, an important family of functional materials with diverse compositions and structures, were traditionally believed inactive towards HER. Encouragingly, the continuous breakthroughs and significant progress in recent years (mainly from 2015 onwards) make engineered metal oxides emerge as promising candidates for HER electrocatalysis. In this article, we present a comprehensive review of recent advances in metal oxide-based electrocatalysts for HER. We start with a brief description of some key fundamental concepts of HER, such as mechanisms, computational activity descriptors, and experimental parameters used to evaluate catalytic performance. This is followed by a overview of various types of metal oxide-based HER electrocatalysts reported so far, including single transition metal oxides, spinel oxides, perovskite oxides, metal (oxy)hydroxides, specially-structured metal oxides and oxide-containing hybrids, with special emphasis on designed strategies for promoting performance and property–activity correlation. Finally, some concluding remarks and perspectives about future opportunities of this exciting field are provided.
294 citations
TL;DR: Overall, it is foreseen that the scope of future membrane applications will become much wider, based on improved existing membrane materials and manufacturing processes, as the combination of novel, tailor-made “building blocks” and “tools” for the fabrication of next-generation membranes tuned to specific applications.
286 citations
TL;DR: The extent to which the participation of lattice oxygen can contribute to the OER is distinguished through the rational design of a model system of silicon-incorporated strontium cobaltite perovskite electrocatalysts with similar surface transition metal properties yet different oxygen diffusion rates.
Abstract: The development of oxygen evolution reaction (OER) electrocatalysts remains a major challenge that requires significant advances in both mechanistic understanding and material design. Recent studies show that oxygen from the perovskite oxide lattice could participate in the OER via a lattice oxygen-mediated mechanism, providing possibilities for the development of alternative electrocatalysts that could overcome the scaling relations-induced limitations found in conventional catalysts utilizing the adsorbate evolution mechanism. Here we distinguish the extent to which the participation of lattice oxygen can contribute to the OER through the rational design of a model system of silicon-incorporated strontium cobaltite perovskite electrocatalysts with similar surface transition metal properties yet different oxygen diffusion rates. The as-derived silicon-incorporated perovskite exhibits a 12.8-fold increase in oxygen diffusivity, which matches well with the 10-fold improvement of intrinsic OER activity, suggesting that the observed activity increase is dominantly a result of the enhanced lattice oxygen participation.
280 citations
TL;DR: This tutorial review intends to show the enormous potential of MXene hydrogels in expanding the application range of both hydrogel and MXenes, as well as increasing the performance of MXenes-based devices.
Abstract: Hydrogels have recently garnered tremendous interest due to their potential application in soft electronics, human-machine interfaces, sensors, actuators, and flexible energy storage. Benefiting from their impressive combination of hydrophilicity, metallic conductivity, high aspect ratio morphology, and widely tuneable properties, when two-dimensional (2D) transition metal carbides/nitrides (MXenes) are incorporated into hydrogel systems, they offer exciting and versatile platforms for the design of MXene-based soft materials with tunable application-specific properties. The intriguing and, in some cases, unique properties of MXene hydrogels are governed by complex gel structures and gelation mechanisms, which require in-depth investigation and engineering at the nanoscale. On the other hand, the formulation of MXenes into hydrogels can significantly increase the stability of MXenes, which is often the limiting factor for many MXene-based applications. Moreover, through simple treatments, derivatives of MXene hydrogels, such as aerogels, can be obtained, further expanding their versatility. This tutorial review intends to show the enormous potential of MXene hydrogels in expanding the application range of both hydrogels and MXenes, as well as increasing the performance of MXene-based devices. We elucidate the existing structures of various MXene-containing hydrogel systems along with their gelation mechanisms and the interconnecting driving forces. We then discuss their distinctive properties stemming from the integration of MXenes into hydrogels, which have revealed an enhanced performance, compared to either MXenes or hydrogels alone, in many applications (energy storage/harvesting, biomedicine, catalysis, electromagnetic interference shielding, and sensing).
265 citations
TL;DR: This work demonstrates a new strategy to develop a highly active and stable Ag single atom in carbon nitride (Ag-N2C2/CN) catalyst with a unique coordination and provides a new idea for the design and synthesis of SACs with novel configurations and excellent catalytic activity and durability.
Abstract: Single atom catalysts (SACs) with the maximized metal atom efficiency have sparked great attention. However, it is challenging to obtain SACs with high metal loading, high catalytic activity, and good stability. Herein, we demonstrate a new strategy to develop a highly active and stable Ag single atom in carbon nitride (Ag-N2 C2 /CN) catalyst with a unique coordination. The Ag atomic dispersion and Ag-N2 C2 configuration have been identified by aberration-correction high-angle-annular-dark-field scanning transmission electron microscopy (AC-HAADF-STEM) and extended X-ray absorption. Experiments and DFT calculations further verify that Ag-N2 C2 can reduce the H2 evolution barrier, expand the light absorption range, and improve the charge transfer of CN. As a result, the Ag-N2 C2 /CN catalyst exhibits much better H2 evolution activity than the N-coordinated Ag single atom in CN (Ag-N4 /CN), and is even superior to the Pt nanoparticle-loaded CN (PtNP /CN). This work provides a new idea for the design and synthesis of SACs with novel configurations and excellent catalytic activity and durability.
229 citations
TL;DR: In this review, the research progress in the design, development, and application of perovskite oxides in PEC water splitting is summarized, with a special emphasis placed on understanding the relationship between the composition/structure and (photo)electrochemical activity.
Abstract: Photoelectrochemical (PEC) water splitting is an attractive strategy for the large-scale production of renewable hydrogen from water. Developing cost-effective, active and stable semiconducting photoelectrodes is extremely important for achieving PEC water splitting with high solar-to-hydrogen efficiency. Perovskite oxides as a large family of semiconducting metal oxides are extensively investigated as electrodes in PEC water splitting owing to their abundance, high (photo)electrochemical stability, compositional and structural flexibility allowing the achievement of high electrocatalytic activity, superior sunlight absorption capability and precise control and tuning of band gaps and band edges. In this review, the research progress in the design, development, and application of perovskite oxides in PEC water splitting is summarized, with a special emphasis placed on understanding the relationship between the composition/structure and (photo)electrochemical activity.
TL;DR: A color-tunable ultralong organic room temperature phosphorescence polymer through radical multiple component cross-linked copolymerization that paves the way for the development of multicolor bio-labels and smart luminescent materials with long-lived emission at room temperature.
Abstract: Functional materials displaying tunable emission and long-lived luminescence have recently emerged as a powerful tool for applications in information encryption, organic electronics and bioelectronics. Herein, we present a design strategy to achieve color-tunable ultralong organic room temperature phosphorescence (UOP) in polymers through radical multicomponent cross-linked copolymerization. Our experiments reveal that by changing the excitation wavelength from 254 to 370 nm, these polymers display multicolor luminescence spanning from blue to yellow with a long-lived lifetime of 1.2 s and a maximum phosphorescence quantum yield of 37.5% under ambient conditions. Moreover, we explore the application of these polymers in multilevel information encryption based on the color-tunable UOP property. This strategy paves the way for the development of multicolor bio-labels and smart luminescent materials with long-lived emission at room temperature. Functional materials displaying tunable emission and long-lived luminescence are a powerful tool in information encryption, organic electronics and bioelectronics. Here the authors design a color-tunable ultralong organic room temperature phosphorescence polymer through radical multiple component cross-linked copolymerization.
TL;DR: The authors report the formation of skyrmion lattice in the WTe2/Fe3GeTe2 van der Waals heterostructure and a Dzyaloshinskii–Moriya interaction with a large energy density of 1.0 mJm−2.
Abstract: The promise of high-density and low-energy-consumption devices motivates the search for layered structures that stabilize chiral spin textures such as topologically protected skyrmions. At the same time, recently discovered long-range intrinsic magnetic orders in the two-dimensional van der Waals materials provide a new platform for the discovery of novel physics and effects. Here we demonstrate the Dzyaloshinskii-Moriya interaction and Neel-type skyrmions are induced at the WTe2/Fe3GeTe2 interface. Transport measurements show the topological Hall effect in this heterostructure for temperatures below 100 K. Furthermore, Lorentz transmission electron microscopy is used to directly image Neel-type skyrmion lattice and the stripe-like magnetic domain structures as well. The interfacial coupling induced Dzyaloshinskii-Moriya interaction is estimated to have a large energy of 1.0 mJ m-2. This work paves a path towards the skyrmionic devices based on van der Waals layered heterostructures.
19 Feb 2020
TL;DR: This review assesses the occurrence and variability of ARGs in livestock wastes and their potential propagation pathways to human pathogens, and evaluates the ARG removal efficiency of common livestock waste management approaches.
Abstract: Antibiotics are widely used in animal husbandry, and various types of antibiotic resistance genes (ARGs) are frequently detected in livestock waste around the world. Conventional livestock waste treatment processes do not completely remove ARGs, resulting in their release to soil and water environments. Various exposure routes of these ARGs to humans, including inhalation and ingestion of antibiotic-resistant bacteria (ARB) that harbor them, may be contributing to the rise in resistant clinical infections that are increasingly difficult to treat with antibiotics. In this review, we assess the occurrence and variability of ARGs in livestock wastes and their potential propagation pathways to human pathogens. We also review the mechanisms and environmental factors that influence the dissemination of ARGs through these pathways, and evaluate the ARG removal efficiency of common livestock waste management approaches. Challenges and research needs for assessing and mitigating the risk of antibiotic resistance dissemination from livestock waste are also presented.
TL;DR: This review is aimed at providing an insightful design guideline and a clear overview of Aza-BODIPY dyes, which might entice new ideas and directions in this field.
Abstract: Boron-dipyrromethene (BODIPY) belongs to a family of organoboron compounds, commercialized as fluorescent dyes by Invitrogen™. As BODIPY derivatives, Aza-boron-dipyrromethene (Aza-BODIPY) dyes display superior spectral performances, such as red-shifted spectra and high molar extinction coefficients, and are considered to be extremely attractive organic materials for various bioapplications. Therefore, scientists from different disciplinary backgrounds would benefit from a review that provides a timely summary and outlook regarding Aza-BODIPY dyes. In this review, we report on the latest advances of Aza-BODIPY dyes, along with the empirical design guidelines and photophysical property manipulation of these dyes. In addition, we will discuss the biological applications of Aza-BODIPY dyes in probing various biological activities, as well as in fluorescence bioimaging/detection, newly-emerging photoacoustic bioimaging/detection, and phototherapy together with future challenges and implications in this field. We aim at providing an insightful design guideline and a clear overview of Aza-BODIPY dyes, which might entice new ideas and directions.
TL;DR: In this paper, the authors proposed the strategy of tailoring strain delocalization to evade long-standing strength-ductility trade-off dilemma, where the achieving of strengthductility synergy depends on the delocalizing of localized strains.
TL;DR: It is demonstrated that L1057 NPs behave as an excellent theranostic system for NIR-II imaging and PTT under safe laser fluence and have great potential for a wide range of biomedical applications.
Abstract: Theranostic systems combining fluorescence imaging in the second near-infrared window (NIR-II, 1000-1700 nm) and photothermal therapy (PTT) under safe laser fluence have great potential in preclinical research and clinical practice, but the development of such systems with sufficient effective NIR-II brightness and excellent photothermal properties is still challenging. Here we report a theranostic system based on semiconducting polymer nanoparticles (L1057 NPs) for NIR-II fluorescence imaging and PTT under a 980 nm laser irradiation, with low (25 mW/cm2) and high (720 mW/cm2) laser fluence, respectively. Taking into consideration multiple parameters including the extinction coefficient, the quantum yield, and the portion of emission in the NIR-II region, L1057 NPs have much higher effective NIR-II brightness than most reported organic NIR-II fluorophores. The high brightness, together with good stability and excellent biocompatibility, allows for real-time visualization of the whole body and brain vessels and the detection of cerebral ischemic stroke and tumors with high clarity. The excellent photothermal properties and high maximal permissible exposure limit at 980 nm allow L1057 NPs for PTT of tumors under safe laser fluence. This study demonstrates that L1057 NPs behave as an excellent theranostic system for NIR-II imaging and PTT under safe laser fluence and have great potential for a wide range of biomedical applications.
TL;DR: In this article, the authors summarized the recent progress in the development of MOFs-derived porous carbons and metal oxide/sulfide compounds and their applications in supercapacitors.
TL;DR: A molecular bridge strategy is reported, in which an interlaminar short-chain molecular bridge generates a robust GO laminate that resists the tendency to swell that can exhibit outstanding durability in harsh operating conditions, such as cross-flow, high-pressure, and long-term filtration.
Abstract: Recent innovations highlight the great potential of two-dimensional graphene oxide (GO) films in water-related applications. However, undesirable water-induced effects, such as the redispersion and peeling of stacked GO laminates, greatly limit their performance and impact their practical application. It remains a great challenge to stabilize GO membranes in water. A molecular bridge strategy is reported in which an interlaminar short-chain molecular bridge generates a robust GO laminate that resists the tendency to swell. Furthermore, an interfacial long-chain molecular bridge adheres the GO laminate to a porous substrate to increase the mechanical strength of the membrane. By rationally creating and tuning the molecular bridges, the stabilized GO membranes can exhibit outstanding durability in harsh operating conditions, such as cross-flow, high-pressure, and long-term filtration. This general and scalable stabilizing approach for GO membranes provides new opportunities for reliable two-dimensional laminar films used in aqueous environments.
TL;DR: In this article, an overview of the structural and electronic band characteristics of GeTe-based thermoelectric materials is presented, and it is recognized that the performance of Gete-based materials can be further enhanced through synergistic effects, such as carrier concentration optimization, band structure engineering, and restrained lattice thermal conductivity.
Abstract: High-performance GeTe-based thermoelectrics have been recently attracting growing research interest. Here, an overview is presented of the structural and electronic band characteristics of GeTe. Intrinsically, compared to low-temperature rhombohedral GeTe, the high-symmetry and high-temperature cubic GeTe has a low energy offset between L and sigma points of the valence band, the reduced direct bandgap and phonon group velocity, and as a result, high thermoelectric performance. Moreover, their thermoelectric performance can be effectively enhanced through either carrier concentration optimization, band structure engineering (bandgap reduction, band degeneracy, and resonant state engineering), or restrained lattice thermal conductivity (phonon velocity reduction or phonon scattering). Consequently, the dimensionless figure of merit, ZT values, of GeTe-based thermoelectric materials can be higher than 2. The mechanical and thermal stabilities of GeTe-based thermoelectrics are highlighted, and it is found that they are suitable for practical thermoelectric applications except for their high cost. Finally, it is recognized that the performance of GeTe-based materials can be further enhanced through synergistic effects. Additionally, proper material selection and module design can further boost the energy conversion efficiency of GeTe-based thermoelectrics.
TL;DR: In this article, an effective and facile strategy is reported for improving the power conversion efficiency and stability by introducing an N719 dye interlayer, which plays multifunctional roles such as broadening the absorption spectrum, suppressing the charge carrier recombination, accelerating the hole extraction, and constructing an appropriate energy level alignment.
Abstract: Perovskite solar cells (PSCs) are highly promising next-generation photovoltaic devices because of the cheap raw materials, ideal band gap of ≈1.5 eV, broad absorption range, and high absorption coefficient. Although lead-based inorganic-organic PSC has achieved the highest power conversion efficiency (PCE) of 25.2%, the toxic nature of lead and poor stability strongly limits the commercialization. Lead-free inorganic PSCs are potential alternatives to toxic and unstable organic-inorganic PSCs. Particularly, double-perovskite CsAgBiBr-based PSC has received interests for its all inorganic and lead-free features. However, the PCE is limited by the inherent and extrinsic defects of CsAgBiBr films. Herein, an effective and facile strategy is reported for improving the PCE and stability by introducing an N719 dye interlayer, which plays multifunctional roles such as broadening the absorption spectrum, suppressing the charge carrier recombination, accelerating the hole extraction, and constructing an appropriate energy level alignment. Consequently, the optimizing cell delivers an outstanding PCE of 2.84%, much improved as compared with other CsAgBiBr-based PSCs reported so far in the literature. Moreover, the N719 interlayer greatly enhances the stability of PSCs under ambient conditions. This work highlights a useful strategy to boost the PCE and stability of lead-free CsAgBiBr-based PSCs simultaneously, accelerating the commercialization of PSC technology.
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TL;DR: A review on the recent development of printed gas sensors can be found in this article, where a variety of gas sensing materials including metal oxides, conducting polymers, carbon nanotubes and two-dimensional (2D) materials are discussed.
Abstract: The rapid development of the Internet of Things (IoT)-enabled applications and connected automation are increasingly making sensing technologies the heart of future intelligent systems. The potential applications have wide-ranging implications, from industrial manufacturing and chemical process control to agriculture and nature conservation, and even to personal health monitoring, smart cities, and national defence. Devices that can detect trace amounts of analyte gases represent the most ubiquitous of these sensor platforms. In particular, the advent of nanostructured organic and inorganic materials has significantly transformed this field. Highly sensitive, selective, and portable sensing devices are now possible due to the large surface to volume ratios, favorable transport properties and tunable surface chemistry of the sensing materials. Here, we present a review on the recent development of printed gas sensors. We first introduce the state-of-the-art printing techniques, and then describe a variety of gas sensing materials including metal oxides, conducting polymers, carbon nanotubes and two-dimensional (2D) materials. Particular emphases are given to the working principles of the printing techniques and sensing mechanisms of the different material systems. Strategies that can improve sensor performance via materials design and device fabrication are discussed. Finally, we summarize the current challenges and present our perspectives in opportunities in the future development of printed gas sensors.
02 Dec 2020
TL;DR: In this article, a new class of transition metal-based nanomaterials for the oxygen evolution reaction (OER) in alkaline electrolyzers has been proposed, which can achieve highly active OER species by a rapid and deep self-reconstruction.
Abstract: Summary Transition metal-based nanomaterials represent an emerging class of highly active and low-cost precatalysts for the oxygen evolution reaction (OER) in alkaline electrolyzers. However, most OER precatalysts undergo slow or incomplete self-reconstructions to generate real active sites, which is a time-consuming process for achieving high OER performance. Thus, we report a new class of OER precatalysts that can achieve highly active OER species by a rapid and deep self-reconstruction (denoted by SELF-RECON). The precatalysts with a core-shell structure comprising NiMoO4 (core) and NiFe/NiFeOx nanoparticles in N-doped amorphous carbons (shell) (denoted by NiMoFeO@NC), can realize rapid MoO42− dissolution and fast formation of NiOOH with Fe incorporation simultaneously. In situ Raman spectroscopy together with electron microscopy, X-ray photoelectron spectroscopy, and electrochemical tests indicate that the obtained NiFeOOH/NiFe-LDH after SELF-RECON behave as the real active species that outperform NiMoFeO@NC, with ultralow overpotentials and extraordinary long-term stability.
TL;DR: In this paper, a wet-chemical synthetic method was developed to prepare the single-layer MoS2-coated polyhedral Ag core-shell heterostructure (Ag@MoS2) with tunable sizes as efficient catalysts for the electrochemical hydrogen evolution reaction (HER).
Abstract: Understanding the reaction mechanism for the catalytic process is essential to the rational design and synthesis of highly efficient catalysts. MoS2 has been reported to be an efficient catalyst toward the electrochemical hydrogen evolution reaction (HER), but it still lacks direct experimental evidence to reveal the mechanism for MoS2-catalyzed electrochemical HER process at the atomic level. In this work, we develop a wet-chemical synthetic method to prepare the single-layer MoS2-coated polyhedral Ag core-shell heterostructure (Ag@MoS2) with tunable sizes as efficient catalysts for the electrochemical HER. The Ag@MoS2 core-shell heterostructures are used as ideal platforms for the real-time surface-enhanced Raman spectroscopy (SERS) study owing to the strong electromagnetic field generated in the plasmonic Ag core. The in situ SERS results provide solid Raman spectroscopic evidence proving the S-H bonding formation on the MoS2 surface during the HER process, suggesting that the S atom of MoS2 is the catalytic active site for the electrochemical HER. It paves the way on the design and synthesis of heterostructures for exploring their catalytic mechanism at atomic level based on the in situ SERS measurement.
19 Nov 2020
TL;DR: This is the first time worldwide, Sars-CoV-2 were isolated from the imported frozen cod outer package's surface, which showed that imported frozen food industry could import SARS-Cov-2 virus.
Abstract: Coronavirus disease 2019 (COVID-19) pandemic has spread in 220 countries/regions to wreak havoc to human beings around the world. At present, the second wave of COVID-19 has begun in many European countries. The complete control of COVID-19 is very urgent. Although China quickly brought the virus under control, there have been eight sporadic outbreaks in China since then. Both in Xinfadi of Beijing and Dalian outbreak of COVID-19, environmental swab samples related to imported cold chain food were tested nucleic acid positive for SARS-CoV-2. In this outbreak in Qingdao, we directly isolated SARS-CoV-2 from the cod outer package's surface swab samples. This is the first time worldwide, SARS-CoV-2 were isolated from the imported frozen cod outer package's surface, which showed that imported frozen food industry could import SARS-CoV-2 virus.
TL;DR: The latest advances in H2O2-responsive materials, including organic and inorganic materials for enhanced PDT are outlined, highlighting the key drawback associated with hypoxia at the tumor microenvironment.
Abstract: Photodynamic therapy (PDT), as one of the noninvasive clinical cancer phototherapies, suffers from the key drawback associated with hypoxia at the tumor microenvironment (TME), which plays an important role in protecting tumor cells from damage caused by common treatments. High concentration of hydrogen peroxide (H2O2), one of the hallmarks of TME, has been recognized as a double-edged sword, posing both challenges, and opportunities for cancer therapy. The promising perspectives, strategies, and approaches for enhanced tumor therapies, including PDT, have been developed based on the fast advances in H2O2-enabled theranostic nanomedicine. In this review, we outline the latest advances in H2O2-responsive materials, including organic and inorganic materials for enhanced PDT. Finally, the challenges and opportunities for further research on H2O2-responsive anticancer agents are envisioned .
TL;DR: The boron-doped Fe-N-C single-atom nanozymes with an intrinsic charge transfer can achieve vivid mimicking nature peroxidase and finally show their promising applications in the detection of enzyme activity and small molecule.
TL;DR: The proof-of-concept experiment demonstrates that 2D-encoded patterns based on dual-mode emitting nanomaterials are very promising for anti-counterfeiting applications, and is believed that this preliminary study will advance the development of the fluorescent materials for potential applications in anti- counterfeiting and optical multiplexing.
Abstract: Developing advanced luminescent materials and techniques is of significant importance for anti-counterfeiting applications, and remains a huge challenge. In this work, a new and efficient approach for achieving efficient dual-mode luminescence with tunable color outputs via Gd3+ -mediated interfacial energy transfer, Ce3+ -assisted cross-relaxation, and core-shell nanostructuring strategy is reported. The introduction of Ce3+ into the inner core not only serves the regulation of upconversion emission, but also facilitates the ultraviolet photon harvesting and subsequent energy transfer to downshifting (DS) activators in the outer shell layer. Furthermore, the construction of the core@shell nanoarchitecture enables the spatial separation of upconverting activators and DS centers, which greatly suppresses their adverse cross-relaxation processes. Consequently, efficient and multicolor-tunable dual-mode emissions can be simultaneously observed in the pre-designed NaGdF4 :Yb/Ho/Ce@NaYF4 :X (X = Eu, Tb, Sm, Dy) core-shell nanostructures under 254 nm ultraviolet light and 980 nm laser excitation. The proof-of-concept experiment demonstrates that 2D-encoded patterns based on dual-mode emitting nanomaterials are very promising for anti-counterfeiting applications. It is believed that this preliminary study will advance the development of the fluorescent materials for potential applications in anti-counterfeiting and optical multiplexing.
TL;DR: A novel donor-acceptor (D-A) COF that was constructed by the Schiff base reaction of carbazole-triazine based D-A monomers and possessed a suitable energy band structure, strong visible-light-harvesting and rich nitrogen sites and DFT calculations suggest that nitrogen atoms in the triazine rings may be photocatalytic active sites.
Abstract: Visible-light-driven CO2 reduction to valuable chemicals without sacrificial agents and cocatalysts remains challenging, especially for metal-free photocatalytic systems. Herein, a novel donor-acceptor (D-A) covalent organic framework (CT-COF) was constructed by the Schiff-base reaction of carbazole-triazine based D-A monomers and possessed a suitable energy band structure, strong visible-light-harvesting, and abundant nitrogen sites. CT-COF as a metal-free photocatalyst could reduce CO2 with gaseous H2 O to CO as the main carbonaceous product with approximately stoichiometric O2 evolution under visible-light irradiation and without cocatalyst. The CO evolution rate (102.7 μmol g-1 h-1 ) was 68.5 times that of g-C3 N4 under the same conditions. In situ Fourier-transform (FT)IR analysis indicated that CT-COF could adsorb and activate the CO2 and H2 O molecules and that COOH* species may be a key intermediate. DFT calculations suggested that nitrogen atoms in the triazine rings may be photocatalytically active sites.