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The advancement of rechargeable Mg-metal batteries (RMBs) is severely impeded by the lack of suitable cathode materials. Despite the good cyclic stability of intercalation-type compounds, their specific capacity is relatively low. Conversely, the conversion-type cathodes can deliver a higher capacity but often suffer from poor cycling reversibility and stability. Herein, a WSe 2 /Se intercalation-conversion hybrid material with elemental Se uniformly distributed into WSe 2 nanosheets is fabricated via a simple solvothermal method for high-performance RMBs. The uniformly introduced Se confined in WSe 2 nanosheets can not only efficiently improve the conductivity of the hybrid cathodes, facilitating the fast electron transport and ion diffusion, but also provide additional specific capacity. Besides, the WSe 2 can effectively inhibit the detrimental Se dissolution and polyselenide shuttle, thereby activating the activity of Se and improving its utilization. Consequently, the synergy of intercalation and conversion mechanisms endows WSe 2 /Se hybrids with superior reversible capacity of 252 mAh g -1  at 0.1 A g -1 and ultra-long cyclability of up to 5000 cycles at 2.0 A g -1 with capacity retention of 78.1%. This work demonstrates the feasibility of the strategy by integrating intercalation and conversion mechanisms for developing high-performance cathode materials for RMBs., (© 2024 Wiley‐VCH GmbH.)

Background: Endothelial barrier disruption of human pulmonary vascular endothelial cells (HPVECs) is an important pathogenic factor for acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). Mesenchymal stem cells-exosome (MSCs-Exo) represents an ideal carrier for cell-free therapy. The therapeutic implication and underlying mechanism of human placental MSCs-Exo (HPMSCs-Exo) in ALI/ARDS need to be further explored., Materials and Methods: HPMSCs-Exo was extracted from HPMSCs and characterized. Then, the therapeutic effects of exosomes were evaluated in ALI mice and HPVECs. RNA-sequencing was applied to reveal the miRNA profile of HPMSCs-Exo and differentially expressed genes (DEGs) in HPMSCs-Exo-pretreated HPVECs. The targets of miRNAs were predicted by bioinformatics methods and correlated to DEGs. Finally, the role of hsa-miR-148a-3p/ROCK1 pathway in HPVECs has been further discussed., Results: The results showed that HPMSCs-Exo could downregulate Rho-associated coiled-coil-containing protein kinase 1 (ROCK1), upregulate the expression of zonula occludens-1 (ZO-1) and F-actin, promote HPVECs migration and tube formation, reduce cytoskeletal disorders and cell permeability, and thus improve ALI/ARDS. RNA-sequencing revealed the DEGs were mainly enriched in cell junction, angiogenesis, inflammation, and energy metabolism. HPMSCs-Exo contains multiple miRNAs which are associated with cytoskeletal function; the expression abundance of hsa-miR-148a-3p is the highest. Bioinformatic analysis identified ROCK1 as a target of hsa-miR-148a-3p. The overexpression of hsa-miR-148a-3p in HPMSCs-Exo promoted the migration and tube formation of HPVECs and reduced ROCK1 expression. However, the overexpression of ROCK1 on HPVECs reduced the therapeutic effect of HPMSCs-Exo., Conclusions: HPMSCs-Exo represents a protective regimen against endothelial barrier disruption of HPVECs in ALI/ARDS, and the hsa-miR-148a-3p/ROCK1 pathway plays an important role in this therapeutics implication., Competing Interests: The authors have no conflict of interest., (Copyright © 2024 Yuzhen Lv et al.)

Aqueous rechargeable magnesium batteries hold immense potential for intrinsically safe, cost-effective, and sustainable energy storage. However, their viability is constrained by a narrow voltage range and suboptimal compatibility between the electrolyte and electrodes. Herein, we introduce an innovative ternary deep eutectic Mg-ion electrolyte composed of MgCl 2 ·6H 2 O, acetamide, and urea in a precisely balanced 1:1:7 molar ratio. This formulation was optimized by leveraging competitive solvation effects between Mg 2+ ions and two organic components. The full batteries based on this ternary eutectic electrolyte, Mn-doped sodium vanadate (Mn-NVO) anode, and copper hexacyanoferrate cathode exhibited an elevated voltage plateau and high rate capability and showcased stable cycling performance. Ex-situ characterizations unveiled the Mg 2+ storage mechanism of Mn-NVO involving initial extraction of Na + followed by subsequent Mg 2+ intercalation/deintercalation. Detailed spectroscopic analyses illuminated the formation of a pivotal solid-electrolyte interphase on the anode surface. Moreover, the solid-electrolyte interphase demonstrated a dynamic adsorption/desorption behavior, referred to as the "breathing effect", which substantially mitigated undesired dissolution and side reactions of electrode materials. These findings underscore the crucial role of rational electrolyte design in fostering the development of a favorable solid-electrolyte interphase that can significantly enhance compatibility between electrode materials and electrolytes, thus propelling advancements in aqueous multivalent-ion batteries.

Rechargeable magnesium batteries (RMBs) show great potential in large-scale energy storage systems, due to Mg 2+ with high polarity leading to strong interactions within the cathode lattice, and the limited discovery of functional cathode materials with rapid kinetics of Mg 2+ diffusion and desirable cyclability retards their development. Herein, we innovatively report the confined synthesis of VS 2 /polyaniline (VS 2 /PANI) hybrid nanosheets. The VS 2 /PANI hybrids with expanded interlayer spacing are successfully prepared through the exfoliation of VS 2 and in situ polymerization between VS 2 nanosheets and aniline. The intercalated PANI increases the interlayer spacing of VS 2 from 0.57 to 0.95 nm and improves its electronic conductivity, leading to rapid Mg-ion diffusivity of 10 -10 -10 -12 cm 2 s -1 . Besides, the PANI sandwiched between layers of VS 2 is conducive to maintaining the structural integrity of electrode materials. Benefiting from the above advantages, the VS 2 /PANI-1 hybrids present remarkable performance for Mg 2+ storage, showing high reversible discharge capacity (245 mA h g -1 at 100 mA g -1 ) and impressive long lifespan (91 mA h g -1 after 2000 cycles at 500 mA g -1 ). This work provides new perspectives for designing high-performance cathode materials based on layered materials for RMBs.

Multivalent ion batteries have attracted great attention because of their abundant reserves, low cost and high safety. Among them, magnesium ion batteries (MIBs) have been regarded as a promising alternative for large-scale energy storage device owing to its high volumetric capacities and unfavorable dendrite formation. However, the strong interaction between Mg 2+ and electrolyte as well as cathode material results in very slow insertion and diffusion kinetics. Therefore, it is highly necessary to develop high-performance cathode materials compatible with electrolyte for MIBs. Herein, the electronic structure of NiSe 2 micro-octahedra was modulated by nitrogen doping (N-NiSe 2 ) through hydrothermal method followed by a pyrolysis process and this N-NiSe 2 micro-octahedra was used as cathode materials for MIBs. It is worth noting that N-NiSe 2 micro-octahedra shows more redox active sites and faster Mg 2+ diffusion kinetics compared with NiSe 2 micro-octahedra without nitrogen doping. Moreover, the density functional theory (DFT) calculations indicated that the doping of nitrogen could improve the conductivity of active materials on the one hand, facilitating Mg 2+ ion diffusion kinetics, and on the other hand, nitrogen dopant sites could provide more Mg 2+ adsorption sites. As a result, the N-NiSe 2 micro-octahedra cathode exhibits a high reversible discharge capacity of 169 mAh g -1 at the current density of 50 mA g -1 , and a good cycling stability over 500 cycles with a maintained discharge capacity of 158.5 mAh g -1 . This work provides a new idea to improve the electrochemical performance of cathode materials for MIBs by the introduction of heteroatom dopant., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Layered double hydroxides (LDHs) have been intensively investigated as promising cathodes for the new concept chloride ion battery (CIB) with multiple advantages of high theoretical energy density, abundant raw materials and unique dendrite-free characteristics. However, driven by the great compositional diversity, a complete understanding of interactions between metal cations, as well as a synergetic effect between metal cations and lattice oxygen on LDH host layers in terms of the reversible Cl-storage capability, is still a crucial but elusive issue. In this work, we synthesized a series of chloride-inserted trinary Mo x -doped NiCo 2 -Cl LDH ( x = 0, 0.1, 0.2, 0.3, 0.4, and 0.5) with gradient oxygen vacancies as enhanced cathodes toward CIBs. The combination of advanced spectroscopic techniques and theoretical calculations reveals that the Mo dopant facilitates oxygen vacancy formation and varies the valence states of coordinated transition metals, which can not only tune the electronic structure effectively and promote Cl-ion diffusion, but improve the redox activity of LDHs. The optimized Mo 0.3 NiCo 2 -Cl LDH delivers a reversible discharge capacity of 159.7 mA h g -1 after 300 cycles at 150 mA g -1 , which is almost a triple enhancement compared to that of NiCo 2 Cl LDH. The superior Cl-storage of trinary Mo 0.3 NiCo 2 Cl LDH is attributed to the reversible intercalation/deintercalation of chloride ions in the LDH gallery along with the oxidation state changes in Ni 0 /Ni 2+ /Ni 3+ , Co 0 /Co 2+ /Co 3+ and Mo 4+ /Mo 6+ couples. This simple vacancy engineering strategy provides critical insights into the significance of the chemical interaction of various components on LDH laminates and aims to effectively design more LDH-based cathodes for CIBs, which can even be extended to other halide-ion batteries like fluoride ion batteries and bromide ion batteries.

Objective To investigate the effects of lipopolysaccharide (LPS) on human pulmonary vascular endothelial cells (HPVECs) cytoskeleton and perform biological analysis of the microRNA (miRNA) spectrum. Methods The morphology of HPVECs was observed by microscope, the cytoskeleton by FITC-phalloidin staining, and the expression of VE-cadherin was detected by immunofluorescence cytochemical staining; the tube formation assay was conducted to examine the angiogenesis, along with cell migration test to detect the migration, and JC-1 mitochondrial membrane potential to detect the apoptosis. Illumina small-RNA sequencing was used to identify differentially expressed miRNAs in NC and LPS group. The target genes of differentially expressed miRNAs were predicted by miRanda and TargetScan, and the functional and pathway enrichment analysis was performed on Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Further biological analysis of related miRNAs was carried out. Results After the LPS got induced, the cells became round and the integrity of cytoskeleton was destroyed. The decreased expression of VE-cadherin was also observed, along with the decreased ability of angiogenesis and migration, and increased apoptosis. Sequencing results showed a total of 229 differential miRNAs, of which 84 miRNA were up-regulated and 145 miRNA were down-regulated. The target gene prediction and functional enrichment analysis of these differential miRNA showed that they were mainly concentrated in pathways related to cell connection and cytoskeleton regulation, cell adhesion process and inflammation. Conclusion In vitro model of lung injury, multiple miRNAs are involved in the process of HPVECs cytoskeleton remodeling, the reduction of barrier function, angiogenesis, migration and apoptosis.

A spin-related photocurrent excited by circularly polarized light is observed near the electrodes on a few-layer ReS 2 sample at room temperature. For both electrodes, the spatial distribution of the spin photocurrent shows a feature of two wings, with one positive and the other negative. In this work, it is suggested that this phenomenon arises from the inverse spin Hall effect due to the local electric field near the electrode. Bias voltage that modulates this field further controls the sign and magnitude of the spin photocurrent. Our research shows that the electric field near the electrodes has a significant impact on the spin transmission operation, and hence it could be taken into account for manufacturing spintronic devices in the future.

Rechargeable magnesium batteries (RMBs) are considered as potential energy storage devices due to their high volumetric specific capacity, good safety, as well as source abundance. Despite extensive efforts devoted to constructing an efficient magnesium battery system, the sluggish Mg 2+ diffusion in conventional cathode materials often leads to slow rate kinetics, low capacity, and poor cycling lifespan. Although transition metal selenides with soft anion frameworks have attracted extensive attention, their Mg 2+ storage mechanism still needs to be clarified. Herein, we demonstrate that the ultrathin CoSe 2 nanoribbons can be used as a robust cathode material for RMBs and reveal a novel Mg 2+ storage mechanism based on cooperative cationic (Co) and anionic (Se) redox processes via systematic ex-situ characterizations. Compared to other metal selenide cathodes based on conversion reactions of solely metal cations, the cooperative cationic-anionic redox reactions of the CoSe 2 cathode contribute to obtaining an enhanced specific capacity and boosted electrochemical kinetics. Moreover, on one hand, the ultrathin nanoribbon structure enables effective contact between the electrode material and electrolyte and on the other hand significantly reduces the length and time consumption of Mg 2+ diffusion, leading to dominated surface-driven capacitance-controlled Mg 2+ storage behavior and rapid Mg 2+ storage kinetics. As a result, the ultrathin CoSe 2 nanoribbon cathode exhibits a reversible discharge capacity of ∼130 mAh g -1 at 100 mA g -1 , good rate capability (116 mAh g -1 at 300 mA g -1 ), and long cyclability over 600 cycles. This finding confirms the development potentiality of polyvalent metal selenide cathode materials based on a cooperative cationic-anionic redox mechanism for the construction of next-generation multivalent secondary batteries.

The large volume expansion and poor electrical conductivity of copper phosphide (Cu 3 P) during the cycle limit their further application as anode of lithium-ion batteries. Therefore, polyvinylpyrrolidone (PVP) modified Cu 3 (BTC) 2 -derived (BTC = 1, 3, 5-Benzentricarboxylic acid) in-situ N/P-co-doped Octahedron carbon encapsulated Cu 3 P nanoparticles (Cu 3 P@NPC) are successfully prepared through a two-step process of carbonization and phosphating. The N/P-co-doped Octahedron carbon matrix improves the conductivity of Cu 3 P and moderates the volume expansion during the lithiation/delithiation process. Meanwhile, the interaction between the Cu 3 P and the doped carbon matrix is methodically explored by using density functional theory (DFT). Through the analysis of the partial charge density, the density of states and the Bader charge, and the calculation results verify the correctness of the experimental observation results, that is, Cu 3 P@NPC has good electrochemical performance. The results show that Cu 3 P@NPC, as the anode of Lithium-ion batteries, has excellent electrochemical performance: it exhibits satisfactory rate performance (251.9 mAh g -1 at 5.0 A g -1 ) and excellent cycle performance (336.4 mAh g -1 at 1 A g -1 over 1000 cycles). This article provides an effective strategy for the encapsulation of metal phosphide nanoparticles in a doped carbon matrix., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Inc. All rights reserved.)

The conversion of chemically inert carbon dioxide and its photoreduction to value-added products have attracted enormous attention as an intriguing prospect for utilizing the principal greenhouse gas CO 2 . Herein, we explore the use of Ag 25 clusters with well-defined atomic structures for high-selectivity photocatalytic hydrogenation of CO 2 to methane. Ag 25 clusters, with molecular-like properties and surface plasmon resonance, exhibit competitive catalytic activity for light-driven CO 2 reduction that yield an almost 100% product selectivity of methane at a relatively mild temperature (100 °C). DFT calculations reveal that the absorption of CO 2 on Ag 25 clusters is energetically favorable. The methanation of the Ag 25 cluster catalyst has been investigated by operando infrared spectroscopy, verifying that methane was produced through a -H-assisted multielectron reaction pathway via the transformation of formyl and formaldehyde species to form surface CH x . This work presents a highly efficient strategy for high-performance CO 2 methanation via well-defined metal cluster catalysts.

Growing electroactive materials directly on a three-dimensional conductive substrate can effectively reduce the "ineffective area" of the electrode during the electrochemical reaction, increase the utilization rate of the material, and thus increase the energy density of the device. Using the network structure of the three-dimensional conductive substrate to design electrode materials with unique microstructures can also improve the stability of the materials. In this work, we obtained different copper-based materials on the copper foam (CF) by in-situ growth method, and designed an independent three-dimensional layered CuO@NiCoFe-S (CuO@NCFS) core-shell nanostructure composite material. CuO@NCFS exhibits excellent electrochemical performance, reaching a specific capacitance of 4551 mF cm -2 at a current density of 1 mA cm -2 with good cycle stability (94.2% after 5000 cycles). In addition, the asymmetric supercapacitor (ASC) uses CuO@NCFS as the positive electrode and rGO as the negative electrode, which can provide an energy rate density of 4.5 mW cm -2 at a high energy density of 99.9 μWh cm -2 . The findings provide some insight into rational design of electrode materials for high performance energy storage., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Functionalized carbon nanomaterials are potential candidates for use as anode materials in potassium-ion batteries (PIBs). The inevitable defect sites in the architectures significantly affect the physicochemical properties of the carbon nanomaterials, thus defect engineering has recently become a vital research area for carbon-based electrodes. However, one of the major issues holding back its further development is the lack of a complete understanding of the effects accounting for the potassium (K) storage of different carbon defects, which have remained elusive. Owing to pressing research demands, the construction strategies, adsorption difficulties, and structure-activity relationships of the carbon defect-involved reaction centers for the K adsorption are systematically summarized using first principles calculations. Carbon defects affect the ability to trap K by affecting the geometry, charge distribution, and conductive behavior of the carbon surface. The results show that carbon doping with pyridinic-N, pyrrolic-N, and P defect sites tend to act as trapping K sites because of electron-deficient sites. However, graphite-N and sulfur doping are less capable of trapping K. In addition, it has been proved using calculations that the defects can inhibit the growth of the K dendrite. Finally, using the molten salt method, we prepared the undoped and nitrogen-doped carbon materials for comparison, verifying the results of the calculation.

Design and fabrication of novel electrode materials with excellent specific capacitance and cycle stability are urgent for advanced energy storage devices, and the combinability of multiple modification methods is still insufficient. Herein, Ni 2+ , Zn 2+ double-cation-substitution Co carbonate hydroxide (NiZnCo-CH) nanosheets arrays were established on 3D copper with controllable morphology (3DCu@NiZnCo-CH). The self-standing scalable dendritic copper offers a large surface area and promotes fast electron transport. The 3DCu@NiZnCo-CH electrode shows a markedly improved electrochemical performance with a high specific capacity of ∼1008 C g -1 at 1 A g -1 (3.2, 2.83, and 1.26 times larger than Co-CH, ZnCo-CH, and NiCo-CH, respectively) and outstanding rate capability (828.8 C g -1 at 20 A g -1 ) due to its compositional and structural advantages. Density functional theory (DFT) calculation results illustrate that cation doping adjusts the adsorption process and optimizes the charge transfer kinetics. Moreover, an aqueous hybrid supercapacitor based on 3DCu@NiZnCo-CH and rGO demonstrates a high energy density of 42.29 Wh kg -1 at a power density of 376.37 W kg -1 , along with superior cycling performance (retained 86.7% of the initial specific capacitance after 10,000 cycles). Impressively, these optimized 3DCu@NiZnCo-CH//rGO devices with ionic liquid can be operated stably in a large potential range of 4 V with greatly enhanced energy density and power capability (110.12 Wh kg -1 at a power density of 71.69 W kg -1 ). These findings may shed some light on the rational design of transition-metal compounds with tunable architectures by multiple modification methods for efficient energy storage.

Solar-driven nitrogen fixation is a promising clean and mild approach for ammonia synthesis beyond the conventional energy-intensive Haber-Bosch process. However, it is still challenging to design highly active, stable, and low-cost photocatalysts for activating inert N 2 molecules. Herein, we report the synthesis of anatase-phase black TiO 2- x S y nanoplatelets enriched with abundant oxygen vacancies and sulfur anion dopants ( V O -S-rich TiO 2- x S y ) by ion exchange method at gentle conditions. The V O -S-rich TiO 2- x S y nanoplatelets display a narrowed bandgap of 1.18 eV and much stronger light absorption that extends to the near-infrared (NIR) region. The co-presence of oxygen vacancies and sulfur dopants facilitates the adsorption of N 2 molecules, promoting the reaction rate of N 2 photofixation. Theoretical calculations reveal the synergistic effect of oxygen vacancies and sulfur dopants on visible-NIR light adsorption and photoexcited carrier transfer/separation. The V O -S-rich TiO 2- x S y exhibits improved ammonia yield rates of 114.1 μmol g -1 h -1 under full-spectrum irradiation and 86.2 μmol g -1 h -1 under visible-NIR irradiation, respectively. Notably, even under only NIR irradiation (800-1100 nm), the V O -S-rich TiO 2- x S y can still deliver an ammonia yield rate of 14.1 μmol g -1 h -1 . This study presents the great potential to regulate the activity of photocatalysts by rationally engineering the defect sites and dopant species for room-temperature N 2 reduction.

Tin (Sn) based anode materials have been regarded as promising alternatives for graphite in lithium ion batteries (LIBs) due to their high theoretical specific capacity and conductivity. However, their practical application is severely restrained by the drastic volume variation during cycling processes. Here we report the preparation of intermetallic SnSb nanodots embedded in carbon nanotube reinforced N-doped carbon nanofibers (SnSb-CNTs@NCNFs) as a free-standing and flexible anode for LIBs. In this unique structure, the SnSb nanodots are well protected by the NCNFs and exhibit greatly reduced volume change. The mechanical strength and conductivity of the nanofabric electrode are further improved by the embedded CNTs. Benefiting from these advantages, the SnSb-CNTs@NCNFs anode delivers a high reversible capacity of 815 mA h g -1 at 100 mA g -1 , a high rate capability (370 mA h g -1 at 5000 mA g -1 ) and a long cycle life (451 mA h g -1 after 1000 cycles at 2000 mA g -1 ). When assembled into flexible pouch cells, the full cells based on SnSb-CNTs@NCNFs anodes also exhibit high flexibility and good lithium storage performances.

N2 fixation is one of the most important chemical reactions in the ecosystem of our planet. However, the industrial Haber-Bosch ammonia synthesis process is restricted by harsh reaction conditions (350-550 °C, 150-350 atm) and undesirable environmental effects (a large amount of CO2 emission). Photocatalytic N2 fixation is promising for achieving sustainable ammonia synthesis under ambient conditions with lower energy input and less environmental issues. However, the known photocatalysts for N2 reduction under mild conditions still face the great challenge of very low energy conversion efficiency. Herein, we report a facile solution-phase method to prepare the heterojunctions based on n-type Bi2MoO6 nanorods and oxygen-vacancy-rich p-type BiOBr nanosheets (Bi2MoO6/OV-BiOBr). Originating from the formation of p-n junctions and suitable bandgap configuration, the Bi2MoO6/OV-BiOBr heterojunctions exhibit effective light utilization and photogenerated electron-hole separation properties. Moreover, it is confirmed that the oxygen vacancies on BiOBr nanosheets are propitious to the adsorption and activation of N2 molecules. Benefiting from these merits, the Bi2MoO6/OV-BiOBr heterojunctions exhibit improved photocatalytic performance for N2 conversion to ammonia without any noble metal co-catalysts and sacrificial reagents under ambient conditions.

Antimony (Sb) based anodes with high conductivity and capability have shown great promise for applications in lithium ion batteries (LIBs). However, they often suffer from poor cycling stability because of the drastic volume variation and structural degradation on undergoing lithiation-delithiation processes. Here we demonstrate a novel Sb-based anode with a free-standing structure realized by uniformly implanting intermetallic compound breithauptite (nickel antimonide, NiSb) nanocrystals into nitrogen-doped carbon nanofibers (NiSb@NCNFs). The discharge/charge behavior of NiSb@NCNFs was systematically investigated by ex situ characterization, which revealed a special "dealloying-lithiation/delithiation-realloying" cycling mechanism. The NiSb nanocrystals possess high lithium storage capacity, and the interconnected network of NCNFs can accommodate the volume variation of encapsulated NiSb nanoparticles, while also providing smooth pathways for charge transport. Compared to other Sb-based anodes, the NiSb@NCNF anode presents exceptional reversible capacity (720 mA h g-1 at a current density of 100 mA g-1) and greatly enhanced cycling life at high rates (510 mA h g-1 after 2000 cycles at 2000 mA g-1). Furthermore, the free-standing NiSb@NCNF anode is free of binders, conductive additives and metal current collectors, exhibiting high flexibility and remarkable performances for the construction of flexible and bendable soft-packed full Li-ion pouch cells.

Solar-driven photocatalytic overall water splitting is regarded as one of the ideal strategies to generate renewable hydrogen energy without the initiation of environmental issues. However, there are still a few remaining challenges to develop wide-light-absorption and stable photocatalysts for the simultaneous production of H2 and O2 in pure water without sacrificial reagents. Herein, we report the design and preparation of Z-scheme TiO2/ZnTe/Au nanocorncob heterojunctions by homogeneously decorating Au nanoparticles onto the surface of core-shell TiO2/ZnTe coaxial nanorods for highly efficient overall water splitting. With the appropriate band structure of TiO2/ZnTe heterojunctions and the surface plasmon resonance enhancement of Au nanoparticles, the well-designed TiO2/ZnTe/Au nanocorncob heterojunctions can synergistically make effective utilization of broad-range solar light illunimation and enhance the separation efficency of electron-hole pairs, as evidenced by UV-Vis absorption and time-resolved photoluminescence spectroscopy. Photoelectrochemical characterization confirms that the water-splitting reaction on TiO2/ZnTe/Au nanocorncobs is mainly carried out via a two-electron/two-electron transfer process with an intermediate product of H2O2. As a result, the TiO2/ZnTe/Au nanocorncob photocatalyst can generate H2 and O2 with a stoichiometric ratio of 2 : 1 under light irradiation without any sacrificial agents, exhibiting a high H2 production rate of 3344.0 μmol g-1 h-1 and a solar-to-hydrogen (STH) efficiency of 0.98%. Moreover, the TiO2/ZnTe/Au nanocorncob heterojunctions show high stability and well-preserved morphological integrity after long-term photocatalytic tests. This study provides a prototype route to produce clean hydrogen energy from only sunlight, pure water, and rationally-designed heterojunction photocatalysts.

Rechargeable magnesium (Mg) batteries assembled with dendrite-free, safe, and earth-abundant metal Mg anodes potentially have the advantages of high theoretical specific capacity and energy density. Nevertheless, owing to the large polarity of divalent Mg 2+ ions, the insertion of Mg 2+ into electrode materials suffers from sluggish kinetics, which seriously limit the performance of Mg batteries. Herein, we demonstrate an atomic substitution strategy for the controlled preparation of ultrathin black TiO 2- x (B-TiO 2- x ) nanoflakes with rich oxygen vacancies (OVs) and porosity by utilizing ultrathin 2D TiS 2 nanoflakes as precursors. We find out that the presence of OVs in B-TiO 2- x electrode material can greatly improve the electrochemical performances of rechargeable Mg batteries. Both experimental results and density functional theory simulations confirm that the introduction of OVs can remarkably enhance the electrical conductivity and increase the number of active sites for Mg 2+ ion storage. The vacancy-rich B-TiO 2- x nanoflakes exhibit high reversible capacity and good capacity retention after long-term cycling at large current densities. It is hoped that this work can provide valuable insights and inspirations on the defect engineering of electrode materials for rechargeable magnesium batteries.

The catalytic conversion of nitrogen to ammonia is one of the most important processes in nature and chemical industry. However, the traditional Haber-Bosch process of ammonia synthesis consumes substantial energy and emits a large amount of carbon dioxide. Solar-driven nitrogen fixation holds great promise for the reduction of energy consumption and environmental pollution. On the basis of both experimental results and density functional theory calculations, here we report that the oxygen vacancy engineering on ultrathin BiOBr nanosheets can greatly enhance the performance for photocatalytic nitrogen fixation. Through the addition of polymetric surfactant (polyvinylpyrrolidone, PVP) in the synthesis process, V O -BiOBr nanosheets with desirable oxygen vacancies and dominant exposed {001} facets were successfully prepared, which effectively promote the adsorption of inert nitrogen molecules at ambient condition and facilitate the separation of photoexcited electrons and holes. The oxygen defects narrow the bandgap of V O -BiOBr photocatalyst and lower the energy requirement of exciton generation. In the case of the specific surface areas are almost equal, the V O -BiOBr nanosheets display a highly improved photocatalytic ammonia production rate (54.70 μmol·g -1 ·h -1 ), which is nearly 10 times higher than that of the BiOBr nanoplates without oxygen vacancies (5.75 μmol·g -1 ·h -1 ). The oxygen vacancy engineering on semiconductive nanomaterials provides a promising way for rational design of catalysts to boost the rate of ammonia synthesis under mild conditions.

The worldwide unrestrained emission of carbon dioxide (CO 2 ) has caused serious environmental pollution and climate change issues. For the sustainable development of human civilization, it is very desirable to convert CO 2 to renewable fuels through clean and economical chemical processes. Recently, electrocatalytic CO 2 conversion is regarded as a prospective pathway for the recycling of carbon resource and the generation of sustainable fuels. In this review, recent research advances in electrocatalytic CO 2 reduction are summarized from both experimental and theoretical aspects. The referred electrocatalysts are divided into different classes, including metal-organic complexes, metals, metal alloys, inorganic metal compounds and carbon-based metal-free nanomaterials. Moreover, the selective formation processes of different reductive products, such as formic acid/formate (HCOOH/HCOO - ), monoxide carbon (CO), formaldehyde (HCHO), methane (CH 4 ), ethylene (C 2 H 4 ), methanol (CH 3 OH), ethanol (CH 3 CH 2 OH), etc. are introduced in detail, respectively. Owing to the limited energy efficiency, unmanageable selectivity, low stability, and indeterminate mechanisms of electrocatalytic CO 2 reduction, there are still many tough challenges need to be addressed. In view of this, the current research trends to overcome these obstacles in CO 2 electroreduction field are summarized. We expect that this review will provide new insights into the further technique development and practical applications of CO 2 electroreduction.