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Hydrogen is considered a promising clean energy vector with the features of high energy capacity and zero-carbon emission. Water splitting is an environment-friendly and effective route for producing high-purity hydrogen, which contains two important half-cell reactions, namely, the anodic oxygen evolution reaction (OER) and the cathodic hydrogen evolution reaction (HER). At the heart of water splitting is high-performance electrocatalysts that efficiently improve the rate and selectivity of key chemical reactions. Recently, perovskite oxides have emerged as promising candidates for efficient water splitting electrocatalysts owing to their low cost, high electrochemical stability, and compositional and structural flexibility allowing for the achievement of high intrinsic electrocatalytic activity. In this review, we summarize the present research progress in the design, development, and application of perovskite oxides for electrocatalytic water splitting. The emphasis is on the innovative synthesis strategies and a deeper understanding of structure–activity relationships through a combination of systematic characterization and theoretical research. Finally, the main challenges and prospects for the further development of more efficient electrocatalysts based on perovskite oxides are proposed. It is expected to give guidance for the development of novel non-noble metal catalysts in electrochemical water splitting. [ABSTRACT FROM AUTHOR]

• Mo is successfully doped into SrCo 0.5 Fe 0.5 O 3-δ perovskite oxides using a modified sol-gel method. • SrCo 0.5 Fe 0.4 Mo 0.1 O 3-δ requires ∼200 and ∼310 mV overpotentials to reach 10 mA cm−2 for HER and OER. • A current density of 10 mA cm−2 could be achieved by applying a potential of 1.68 V vs. RHE in the SCFM10||SCFM10 electrolyzer. • SrCo 0.5 Fe 0.4 Mo 0.1 O 3-δ exhibits remarkable stability for HER and OER in alkaline electrolyte. Perovskite oxides with high electrocatalytic activities and cost-effectiveness can be developed by rational doping. Here, we fabricate a series of perovskite oxides comprising SrCo 0.5 Fe 0.5-x Mo x O 3-δ (x = 0, 0.05, 0.10, 0.15) doped with different proportions of Fe and Mo elements to enhance the long-term stabilities and electrocatalytic activities for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Among them, SrCo 0.5 Fe 0.4 Mo 0.1 O 3-δ (SCFM10) exhibits the optimum electrocatalytic activity for water splitting, exhibiting overpotentials at −10 mA cm−2 and 10 mA cm−2 of ∼200 mV for HER and ∼310 mV for OER, respectively, generating a current density of 10 mA cm−2 using only 1.68 V in a two-electrode electrolytic cell. Additionally, SCFM10 demonstrates outstanding stability, maintaining continuous operation for 100 h without visible decay. These results give some new points of view into the development of bifunctional catalysts for the purpose of efficient water splitting in a sensible way. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, a well-dispersed Pd nanoparticle (NP)-supported RGO/Mn 3 O 4 (G/M/Pd) composite was synthesized by a clean synthetic route, where galvanic replacement reaction simply occurred between Mn 3 O 4 and a palladium salt, thereby avoiding the use of harsh reducing and capping agents. The G/M/Pd composite served as a robust catalyst for the catalytic oxidation of hydroquinone (HQ) to benzoquinone (BQ) with H 2 O 2 in an aqueous solution. Oxidation was completed in only 4 min, with a turnover frequency (TOF) of 3613 h−1; this TOF is one hundred times those of previously reported Pd- and Ag-based catalysts. The superior performance was related to the electronic inductive effect between Mn 3 O 4 and Pd NPs, which was verified by density functional theory calculations. Trapping experiments revealed that the oxidation of HQ was considerably related to the ·OH radicals generated from the decomposition of H 2 O 2. In addition, the influencing factors were further investigated, including catalyst and HQ concentrations, solution pH, solvents, and various inorganic and organic interferences. Moreover, the G/M/Pd catalyst exhibits diverse applications for the catalytic oxidation of HQ derivatives with high TOFs. [ABSTRACT FROM AUTHOR]

Development of excellent bi-functional electrocatalysts for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) remains a key issue for the commercialization of various electrochemical devices such as fuel cells and metal-air batteries. Herein, we report the synthesis and electrocatalytic performance of mesoporous nanostructured spinel-type MFe 2 O 4 (M = Co, Mn, Ni) oxides which can serve as alternative low-cost bi-functional electrocatalysts for ORR/OER. Loaded on XC-72 carbon support, the MFe 2 O 4 spinel oxides show the M-dependent catalytic activities with CoFe 2 O 4 being the most active electrocatalyst followed by MnFe 2 O 4 and NiFe 2 O 4 for ORR. For the OER, however, the activity increases in the order: MnFe 2 O 4 < NiFe 2 O 4 ≈ CoFe 2 O 4 . Additionally, the CoFe 2 O 4 catalyst shows the smallest overpotential between ORR and OER. Compared with commercial IrO 2 , the MFe 2 O 4 catalysts reveal comparable OER activities. Furthermore, the MFe 2 O 4 catalysts exhibit much better methanol tolerance and stability than Pt/C. Meanwhile, both electrochemical measurements and density functional theory (DFT) calculations verify that the ORRs on the MFe 2 O 4 catalysts are a direct 4 e − pathway in the alkaline solution, and expound the reason for the excellent methanol tolerance of MFe 2 O 4 . [ABSTRACT FROM AUTHOR]

Antimony (Sb) as a low-toxic and cost-effective metal is a promising material to catalyse CO 2 electroreduction to formate with practical viability. However, monometallic Sb suffers from intrinsically low catalytic activity and the competing hydrogen evolution. Here, we report nanoporous Sb-Bi alloys for substantially improving the catalytic activity of Sb and suppressing hydrogen evolution. The optimal Sb-Bi alloy exhibits a maximum Faradaic efficiency of 95.8 % toward formate production, surpassing the 11.6 % of monometallic Sb counterpart. Operating the catalyst in the flow cell demonstrates a formate partial current density of 734 mA cm−2 and cathodic energy efficiency of 59 % at a moderate overpotential of 800 mV, representing a record formate-production performance so far. Experimental and theoretical studies indicate that the Sb-Bi interactions activate Sb sites to selectively stabilize *OCHO intermediates, facilitating CO 2 -to-formate conversion. This work offers insights in manipulating bimetallic interactions to transform inert materials into active catalysts for efficient electrocatalysis. [Display omitted] • Sb-Bi interactions induce electrocatalytic switching from HER to CO 2 ER. • Sb 2 Bi 6 exhibits a maximum formate selectivity of 95.8 % in an H-type cell. • Sb 2 Bi 6 achieves a record formate activity of 734 mA cm−2 in a flow cell. • Sb-Bi interactions facilitate Sb sites to stabilize *OCHO for formate formation. [ABSTRACT FROM AUTHOR]

Transition metal oxalate materials have shown huge competitive advantages for applications in supercapacitors. Herein, nanostructured cobalt oxalate supported on cobalt foils has been facilely fabricated by anodization, and could directly serve as additive/binder-free electrodes for supercapacitors. The as-prepared cobalt oxalate electrodes present superior specific capacitance of 1269 F g −1 at the current density of 6 A g −1 in the galvanostatic charge/discharge test. Moreover, the retained capacitance is as high as 87.2% as the current density increases from 6 A g −1 to 30 A g −1 . More importantly, the specific capacitance of cobalt oxalate retains 91.9% even after super-long cycling of 100,000 cycles. In addition, an asymmetric supercapacitor assembled with cobalt oxalate (positive electrode) and activated carbon (negative electrode) demonstrates excellent capacitive performance with high energy density and power density. [ABSTRACT FROM AUTHOR]

Multi-component nanoporous platinum–ruthenium–copper–osmium–iridium (np-PtRuCuOsIr) electrocatalyst has been facilely fabricated by chemical dealloying of mechanically alloyed AlCuPtRuOsIr precursor. The np-PtRuCuOsIr catalyst exhibits a typical three-dimensional bi-continuous interpenetrating ligament/channel structure with a length scale of ∼2.5 nm. The np-PtRuCuOsIr catalyst reaches a higher level in the mass activity (857.5 mA mg Pt −1 ) and specific activity (3.0 mA cm −2 ) towards methanol oxidation compared to the commercial PtC catalyst (229.5 mA mg Pt −1 and 0.5 mA cm −2 respectively). Moreover, the CO stripping peak of np-PtRuCuOsIr is 0.54 V (vs. SCE), 130 mV negative shift in comparison with the commercial PtC (0.67 V vs. SCE). The half-wave potential of np-PtRuCuOsIr is 0.900 V vs. RHE, 36 mV positive compared with that of the commercial PtC (0.864 V vs. RHE). The np-PtRuCuOsIr catalyst also shows 1.8 and 3.8 times enhancement in the mass and specific activity towards oxygen reduction than the commercial PtC. Moreover, the np-PtRuCuOsIr alloy exhibits superior oxygen reduction activities even after 15 K cycles, indicating its excellent long-term stability. The present np-PtRuCuOsIr can act as a promising candidate for the electrocatalyst in direct methanol fuel cells (DMFCs). [ABSTRACT FROM AUTHOR]

Coralloid-Pt nanodendrites decorated nanoporous gold films (NPG-Ptx) were fabricated through underpotential deposition/in-situ reduction replacement (UPD/IRR) strategy and exhibit significantly enhanced ORR activities. Ab initio density functional theory (DFT) studies further demonstrate the ORR mechanism of NPG-Ptx. [Display omitted] • Coralloid-Pt nanodendrites decorated nanoporous gold films (NPG-Ptx) were fabricated through underpotential deposition/in-situ reduction replacement (UPD/IRR) strategy. • The NPG-Ptx (x = 1 ∼ 4) exhibit significantly enhanced ORR activities in acidic media. • The DFT studies demonstrate the ORR mechanism and rate-determining step of NPG-Ptx follow the free energy diagrams. • The PDOS results indicate a relatively stronger O 2 reaction capacity on Pt side than Pt top. Deposition of trace amounts of Pt onto nanoporous gold ligaments (NPG-Pt) has demonstrated promising performance of low-Pt electrocatalysts for oxygen reduction reaction (ORR); however, improving the activity of ORR remains challenging because of the difficulty in understanding the electronic effect between Pt and NPG as well as the absence of ORR mechanism studies on NPG-Pt. Here we show that NPG-Ptx (x = 1 ∼ 4), unique coralloid-Pt nanodendrites decorated nanoporous gold films through underpotential deposition/in-situ reduction replacement (UPD/IRR) strategy, exhibit significantly enhanced ORR activities. Among them, NPG-Pt3 exhibits the best ORR activity compared with the others and Pt/C in acidic media. Density functional theory (DFT) studies demonstrate the ORR mechanism and rate-determining step of NPG-Ptx follow the free energy diagrams. Furthermore, the projected density of state (PDOS) results reveal a relatively weaker O 2 reaction capacity on the top side of Pt (Pt top) than the side site (Pt side) for NPG-Ptx. The increase of d -band center for NPG-Ptx pushes up the energy of the antibonding state above the Fermi level, and then the backflow of electrons into the system makes the energy more stable, optimizing the ORR activity. These results provide new inspirations for the development of low-Pt electrocatalysts for energy technologies in a rational manner. [ABSTRACT FROM AUTHOR]

Heteroatom doping, especially with elements of lower electronegativity and smaller atomic radius, can effectively modulate the electronic structure and surface properties of electron materials, facilitating the electrochemical performance of supercapacitors. Herein, we have designed boron-doped NiCoP nanoarrays grown on carbon cloth (B-NCP-CC) for supercapacitor cathode materials using a simple process method combining hydrothermal, calcined phosphating and boronation processes. The introduction of boron, with lower electronegativity (2.04) and smaller atomic radius (0.85 Å) than phosphorus (2.19 and 1.00 Å), induces electron redistribution and shortens the Ni/Co–B bonds, enhancing their redox activity and charge transfer kinetics. The boron doping greatly enables the B-NiCoP-CC-18 (NiCoP-CC borated for 18 h) cathode material to provide a high capacity of 801 C g−1. The assembled B-NiCoP-CC-18‖‖AC hybrid supercapacitor achieves a high energy density of 73.22 W h kg−1 at a power density of 963.8 W kg−1 and retains 90% capacity after 5000 cycles, significantly improving the stability of nickel-based materials. Besides, density functional theory (DFT) calculations further elucidate that the introduction of boron increases the d-band centers of Ni and Co in NiCoP, promoting the conductivity and enhancing the electrochemical properties. [ABSTRACT FROM AUTHOR]

Advancing the development of economical, high-performance, and durable non-precious metal electrocatalysts for oxygen evolution reaction (OER) holds critical significance. This study presents a self-supporting ternary metal phosphide (NiCoFe–P/NF) electrode developed by direct phosphating metal-organic frameworks (MOFs) precursor. Benefiting from a three-dimensional hierarchical porous structure, optimized electronic configuration, high electrical conductivity, and synergistic effect of multiple elements, the synthesized NiCoFe–P/NF electrocatalyst exhibits exceptional catalytic performance compared to the monometallic or bimetallic phosphides, achieving a low overpotential of 209 mV and a Tafel slope of 29 mV dec−1 at 10 mA cm−2 in 1 M KOH solution. In addition, the prepared catalyst exhibits superior stability and durability, as evidenced by its well-preserved morphology after 48 h of stability test. Furthermore, at a high current density of 100 mA cm−2, the long-term efficiency remains >90% even after 96 h. Density functional theory (DFT) calculations reveal that the high catalytic performance of the NiCoFe–P/NF catalyst is ascribed to modified electronic states and lower adsorption energy to the related species. This study not only presents the synthesis of extremely stable and active OER catalysts but also offers a novel and practical method for the development of new catalysts. [Display omitted] • Self-supporting trimetallic phosphide was investigated for OER. • NiCoFe–P/NF electrode provides superior OER activity and stability. • DFT calculations explain the origin of the high catalytic activity. • A chemically uniform trimetallic two-dimensional MOF served as the precursor. [ABSTRACT FROM AUTHOR]

Catalysts with multifunctional catalytic properties hold great promise in energy conversion and environmental remediation. Herein, a series of 1D hollow NiO/Bi 2 Mo x W 1−x O 6 (x = 0, 0.25, 0.5, 0.75, 1) nanofibers are fabricated via pyrolysis of electrospinning precursor. Integrating the hollow structural merits of large specific surface area, abundant active sites, and built-in electric field, this novel NiO/Bi 2 Mo x W 1−x O 6 nanofibers act as a bifunctional platform boosting photocatalytic tetracycline conversion and electrocatalytic oxygen reduction. NiO/Bi 2 Mo 0.75 W 0.25 O 6 solid solution nanofiber delivers a 99.5 % photocatalytic degradation in 120 min for tetracycline (TC) solution with attractive stability, outperforming its NiO/Bi 2 MoO 6 or NiO/Bi 2 WO 6 counterparts. Radical trapping experiments show that ∙ O 2 ⁻ is the key oxidative radical in the photocatalytic reaction. Moreover, the NiO/Bi 2 Mo 0.75 W 0.25 O 6 solid solution nanofiber exhibits an improved ORR activity in alkaline media with a half-wave potential of 0.63 V, and Tafel slope of 76 mV dec−1, along with high stability. We expect this work to inspire the design of multi-functional catalysts for photocatalytic water treatment and electrocatalytic energy conversion. • 1D NiO/Bi 2 Mo x W 1−x O 6 (x = 0, 0.25, 0.5, 0.75, 1) nanofibers are fabricated via a pyrolysis of electrospinning precursor. • This NiO/Bi 2 Mo x W 1−x O 6 nanofibers act as a bifunctional platform boosting photocatalytic and electrocatalytic reduction. • NiO/Bi 2 Mo 0.75 W 0.25 O 6 solid solution nanofiber delivers a 99.5 % photocatalytic degradation in 120 min for TC solution. • NiO/Bi 2 Mo 0.75 W 0.25 O 6 solid solution nanofiber exhibits an improved ORR activity and high stability in alkaline media. [ABSTRACT FROM AUTHOR]

Liquid–liquid phase transition (LLPT) is a transition from one liquid state to another with the same composition but distinct structural change, which provides an opportunity to explore the relationships between structural transformation and thermodynamic/kinetic anomalies. Herein the abnormal endothermic LLPT in Pd43Ni20Cu27P10 glass-forming liquid was verified and studied by flash differential scanning calorimetry (FDSC) and ab initio molecular dynamics (AIMD) simulations. The results show that the change of the atomic local structure of the atoms around the Cu-P bond leads to the change in the number of specific clusters <0 2 8 0> and <1 2 5 3>, which leads to the change in the liquid structure. Our findings reveal the structural mechanisms that induce unusual heat-trapping phenomena in liquids and advance the understanding of LLPT. [ABSTRACT FROM AUTHOR]

Electrocatalytic O2 conversion and water-splitting hold great promise to enable the chemicals–electricity inter-transition in many renewable-energy initiatives. Enhancing the kinetics of the oxygen reduction reaction (ORR) is challenging. Here, we present that Zn3(VO4)2/Ni(OH)2/rGO (reduced graphene oxide) nanosheet arrays-a Zn3(VO4)2/Ni(OH)2 composite in the form of nanometre-thick nanosheets on an rGO substrate-serve as an efficient and stable electrocatalyst for the ORR in alkaline electrolytes. The thin-sheet structure and smaller free energy of Zn3(VO4)2/Ni(OH)2, as well as the excellent conductivity of the rGO substrate, enable a large electrochemically-active surface area and a high electron transport, contributing to the superior electrocatalytic oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). Furthermore, Zn3(VO4)2/Ni(OH)2/rGO and Zn3(VO4)2/Ni(OH)2 samples exhibit remarkable long-term water-splitting stability of 48 h. Density functional theory (DFT) calculations reveal the optimized intermediate affinity ability at the Ni(OH)2 side, due to electrons transferring from Ni(OH)2 to Zn3(VO4)2. Additionally, the higher hybridization degree of density of states (DOS) boosts electron transfer in the electrocatalytic process. More broadly, this work provides new inspiration for the construction of a novel noble metal-free electrocatalyst that could show great promise in energy electrocatalysis. [ABSTRACT FROM AUTHOR]

Metallic actuators have attracted a great deal of attention owing to their potential advantages over piezoelectric ceramics and conducting polymers. Here, we report different electrochemical actuation behaviors of bulk nanoporous palladium (np-Pd) fabricated by dealloying in acid (0.5 M H 2 SO 4 ) and alkaline (1.0 M KOH) solutions. In the 1.0 M KOH solution, the reversible expansion/contraction of np-Pd well responds to the adsorption/desorption of involved species (H and OH). In the 0.5 M H 2 SO 4 solution, only continuous contraction can be observed in the potential region involving the H-adsorption/desorption, but the reversible strain appears in the potential region related to the OH-adsorption/desorption. Moreover, the surface stress-charge coefficient (ξ) exhibits inverse signs associated with the H-adsorption (absorption)/desorption and OH-adsorption/desorption in the alkaline solution. More importantly, the reversible strain amplitude of np-Pd can be regulated by changing the potential scan rate or by being stimulated in different electrolytes. [ABSTRACT FROM AUTHOR]

The electrochemically induced electrical resistance response of nanostructured metallic materials is an important issue in interdisciplinary fields including electrochemistry, physics and surface science. Nanoporous metals possess an open three-dimensional bicontinuous ligament (nanowire network)-channel (nanopore) structure with high surface-to-volume ratios, and show great potentials for investigations in this topic. Here we fabricate nanoporous silver (NPS) with high density of lattice defects (dislocations, twins, stacking defaults and grain boundaries) and ligaments composed of Ag nanocrystals with sizes comparable to the ligament length scale. More importantly, the present NPS shows extraordinarily enhanced reversible resistance response to electrochemical stimuli in alkaline electrolytes. A giant reversible resistance change of up to ∼1100% has been achieved in NPS. Moreover, the reversible electrical resistance change of NPS can be well modulated through cyclic voltammetry or square wave potential input. The related mechanisms have been rationalized on the basis of reversible oxide formation/reduction on the ligament surface of NPS, silver dissolution, as well as the effects of lattice defects in NPS. [ABSTRACT FROM AUTHOR]

The pursuit of a desirable photocatalytic technology has always been accompanied by photocatalyst design and development, marking high activity, long-term stability, and low cost. Herein, an in-situ deposition approach is used to integrate plasmonic 0D Ag nanoparticles on the surface of 2D slice-like 2,9,16,23-tetranitrocopper(II) phthalocyanine (CuPc) sensitized 1D Bi 2 MoO 6 nanofibers (Ag-CuPc/Bi 2 MoO 6) for visible-light-induced tetracycline (TC) photocatalysis. Benefiting from the combination of 2D CuPc sensitization, and surface plasmon resonance (SPR) effect of 0D Ag nanoparticles, we experimentally find that the Ag-CuPc/Bi 2 MoO 6 nanofibers boost the visible-light utilization efficiency, promote charge transfer, and separation, and accelerate electron redox transformation in TC photocatalysis. The superior photocatalytic activity is attributed to the strong interfacial interaction, and Z-scheme heterojunction synergy in Ag-CuPc/Bi 2 MoO 6 nanofibers. This work opens new horizons for the delicate design of promising Z-scheme visible-light photocatalysts for the removal of antibiotics in wastewater, realizing water purifications. A novel Ag-decorated CuPc/Bi 2 MoO 6 nanofiber heterojunction photocatalyst was successfully synthesized. Benefiting from the combination of the CuPc sensitization, and the SPR effect of Ag nanoparticles, Ag-CuPc/Bi 2 MoO 6 boosts visible-light utilization efficiency, and promotes the separation efficiency of photogenerated carriers. Therefore, the photocatalytic activity of Ag-CuPc/Bi 2 MoO 6 was improved significantly in tetracycline degradation. [Display omitted] • A novel plasmonic Ag-decorated CuPc/Bi 2 MoO 6 nanofiber was successfully fabricated. • The separation efficiency of e−/h+ was enhanced due to the sensitization of CuPc, and SPR effect of Ag nanoparticles. • Ag-CuPc/Bi 2 MoO 6 exhibited excellent properties in TC degradation. • A possible Z-scheme photocatalytic mechanism was evidenced by MS and ESR analysis. [ABSTRACT FROM AUTHOR]

Electrode materials exhibiting higher structural stability and electrochemical activity remain a priority in improving the electrochemical performance of supercapacitors (SCs). Herein, we report the design and synthesis of a novel nanoplate-on-nanosheet architecture with vertically aligned ZnCo2O4 (ZCO) porous nanoplates anchored on ultrathin delaminated-Ti3C2 (d-TC) nanosheets as a high-performance electrode for electrochemical SCs. The unique robust nanoplate-on-nanosheet adhesion promises fast electron and ion transport, large electroactive surface area, and excellent structural stability. Importantly, benefiting from the features of such a configuration, the ZCO/d-TC-350 composite electrode displays a high specific capacity of 195.8 C g−1 at a current density of 1 A g−1. Moreover, the constructed hybrid supercapacitor (HSC) consisting of ZCO/d-TC-350‖‖active carbon (AC) achieves a high energy density of 15.6 W h kg−1 at a power density of 551.1 W kg−1 and superior long-term stability with 89.5% capacitance retention after 4000 cycles. This work provides a promising strategy for the preparation of advanced MXene-based electrodes for electrochemical capacitors. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ru-doped SrFe 1-x Ru x O 3-δ perovskite oxides were successfully fabricated through a modified sol–gel method. • The SrFe 0.7 Ru 0.3 O 3-δ exhibits significantly enhanced bifunctional electrocatalytic activities for HER and OER in alkaline electrolytes. • The DFT studies demonstrate Ru doping optimizes the electronic structure of SrFe 0.7 Ru 0.3 O 3-δ and thus improves the charge transfer efficiency. • An electrolyzer with SFR30 as both the anode and cathode catalysts requires only a cell voltage of 1.58 V vs. RHE to drive a current density of 10 mA cm−2 in an alkaline medium. Recently, perovskite oxides have acquired a rapidly growing research interest in energy storage and conversion systems, especially the electrolysis of water. Rational doping is an extremely effective strategy to enhance the hydrogen evolution reaction/oxygen evolution reaction (HER/OER) of the perovskite oxides. Herein, a series of novel bi-functional electrocatalysts were synthesized by doping Ru in SrFeO 3-δ perovskite oxide (SrFe 1-x Ru x O 3-δ , x = 0, 0.15, 0.30, 0.45) which exhibit remarkable enhancements of HER/OER activities and long-term stabilities in the alkaline solution (1.0 M KOH). Among them, SrFe 0.7 Ru 0.3 O 3-δ (SFR30) shows the best electrocatalytic activities for overall water splitting, exhibiting low overpotentials for HER (∼41 mV) and OER (∼334 mV) at −10 and 10 mA cm−2, respectively, generating current densities of 10 mA cm−2 in alkaline electrolytic cell using the potential of 1.58 V. In addition, the SFR30 electrocatalyst exhibits remarkable stability which can be operated continuously for 96 h without significant delay. Density functional theory (DFT) calculations indicate that Ru doping can effectively modulate the adsorption of intermediates on the active sites to achieve excellent electrocatalytic performance. Many new prospects have been opened for the development of bi-functional electrocatalysts for overall water splitting. [ABSTRACT FROM AUTHOR]

Given its superior structure, the abundance of surface functional groups, and low cost, cotton fiber filtration paper can be used as the support for hydrogen evolution reaction (HER) and oxygen evolution reaction catalysts (OER) instead of copper foam (CF), nickel foam (NF), or carbon cloth (CC). Herein, the chemical plating method was used to create thin self-supporting electrodes based on cotton fiber filtration paper (FP). The Co-Ni-P amorphous nanospheres can be uniformly dispersed on the self-supporting FP due to its porous structure and oxygen functional groups. The Co-Ni-P/FP electrode has an overpotential as low as 125 mV for HER and 320 mV for OER at the current density of 10 mA cm−2. Additionally, according to density functional theory (DFT) calculations, the Co atom added to the Ni-P nanosphere can lead to considerably more charge accumulation around the Co and Ni active sites, which greatly encourages the HER and OER processes. The novel porous support, FP, provides a fresh way the preparation of self-supporting electrodes. [Display omitted] • Filter paper is used to prepare the self-supporting electrode as the substrate. • The preparation method is simple and the properties are stable. • Rich oxygen-containing functional groups of FP promote deposition and dispersion. • Explore the excellent electrochemical performance of amorphous Co-Ni-P/FP by DFT. [ABSTRACT FROM AUTHOR]

Nanoporous tungsten (np-W) synthesized by a facile dealloying strategy was utilized as the host to accommodate tellurium (Te) for Li-Te batteries. The np-W supported Te (np-W-Te) cathode exhibits an excellent specific volumetric capacity of 1168 mA h cm−3 after 30 cycles, a good cycling performance of 200 cycles with a coulombic efficiency over 98.9%, and fast rate capabilities of 1612 mA h cm−3 at a current density of 50 mA g−1 and 774 mA h cm−3 at 800 mA g−1. The excellent performance of the np-W-Te cathode is attributed to the highly dispersed Te impregnated in the np-W host with rich porosity, high conductivity and superior stability. The mechanism investigation by in situ Raman and ex situ XRD techniques demonstrates the reversible transformation between Li and Li 2 Te during the charge/discharge processes. This study highlights the nanoporous metal as a promising host to confine Te for Li-Te batteries. Nanoporous tungsten synthesized by dealloying acted as the host to accommodate Te for Li-Te batteries. ga1 • The as-dealloyed nanoporous W hosted Te as the cathode for Li-Te batteries. • The cathode exhibited high specific capacity, good cycling and rate performances. • The reversible conversion between Te and Li 2 Te is the mechanism for the battery. [ABSTRACT FROM AUTHOR]

• 1D MWO 4 (M = Zn, Ni, Cu) nanomaterials were synthesized by electrospinning method. • CuWO 4 nanotubes exhibited superior degradation performances under UV–Vis-NIR light. • NIR responses of CuWO 4 and NiWO 4 were explained by metal ion d-d orbital transition. Photocatalysis is a promising technology for addressing environmental pollution and energy shortages in a carbon neutral way, and highly effective utilization of solar light is very important for water treatment via photocatalysis. In this study, we synthesized one-dimensional wolframite-structured MWO 4 (M = Zn, Ni, and Cu) nanomaterials as UV–Vis–NIR broad spectrum-driven photocatalysts via the electrospinning method, and observed the excellent performances in the photocatalytic degradation of tetracycline (TC) and bisphenol A (BPA) under the UV–Vis–NIR light illumination. The degradation experiments showed that CuWO 4 nanotubes exhibited the highest degradation capability, and achieved the TC removal rates of 91.8% and 94.2% after 140 min and 12 h under UV–Vis and NIR light irradiation, respectively. The UV–Vis–NIR responsive photocatalytic activities and mechanisms could be explained by the charge transfer mechanism and metal ion d-d orbital transition based on the experimental results and density functional theory modulations. Our findings demonstrate that the MWO 4 (M = Zn, Ni, and Cu) photocatalysts could be responsive to the UV–Vis–NIR broad-spectrum lights, representing a major step forward in the development of photocatalytic technology. [ABSTRACT FROM AUTHOR]

Abstract The separator is a crucial part of lithium ion battery, such as preventing internal short-circuit and offering ion-conducting routes. However, conventional separators are usually based on polymer materials, which show the low thermal stability and poor electrolyte wettability, thus greatly restricting the electrochemical performance of lithium ion battery, especially for high-temperature safety. In this study, zeolitic imidazolate framework-67 (ZIF-67) was employed as separator via direct coating onto the surface of LiNi 0.5 Co 0.2 Mn 0.3 O 2 electrode through a facile blade-coating technique. Comparing with the conventionally used polypropylene (PP) separator, the new ZIF-67 based separator features superior electrolyte uptake (154%), higher ionic conductivity (0.00164 S cm−1) and thermal stability. Notably, at a high temperature of 55 °C, the cell with ZIF-67 based separator exhibits nearly 2 times higher capacity retention than the PP separator (ZIF-67: 61.20% vs PP: 35.09%). In view of its advantages, the ZIF-67 based separator shows significant potential in the design of safe lithium ion batteries. Graphical abstract Image 1 Highlights • ZIF-67 is demonstrated to use as the separator. • ZIF-67 based separator is directly coated on the LiNi 0.5 Co 0.2 Mn 0.3 O 2 electrode. • ZIF-67 based separator has higher thermal stability than polypropylene separator. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hierarchical 1D/2D Ni(OH) 2 /PCC is fabricated via a facile hydrothermal route as the positive electrode. • The porous corn stigma-derived carbon with the 3D open framework is preparated as the negative electrode. • Explore the excellent electrochemical performance of 1D/2D Ni(OH) 2 /PCC by DFT. • The hybrid supercapacitor displays supeiror energy and power density. Enhancing the energy density of supercapacitors is of great scientific and technological importance, producing a larger energy density than traditional symmetrical carbon supercapacitors. Herein, a hybrid supercapacitor based on an activated corn stigma-derived carbon (PCC) electrode combined with a large-capacity faradic 1D nanofiber/2D nanosheet Ni(OH) 2 electrode is designed to fulfill this goal. Benefiting from the highly conductive, porous construction, and 3D open framework of PCC electrode couple with unique hierarchical 1D nanofiber/2D nanosheet Ni(OH) 2 , such 1D/2D Ni(OH) 2 /PCC electrode is capable of increasing accessible active sites, shortening ion-diffusion path, and accelerating mass transfer. More importantly, DFT calculations unveil that 1D/2D Ni(OH) 2 /PCC composites own high electrical conductivity and OH– adsorption energy. Therefore, the specific capacity of the 1D/2D Ni(OH) 2 /PCC composite electrode reaches 655.9C g−1 at the current density of 1 A/g. Moreover, such hybrid 1D/2D Ni(OH) 2 /PCC||PCC supercapacitor show an outstanding energy density and power density of 38.6 Wh kg−1, and 1.03 kW kg−1, respectively. This work provides the possibility of fabricating hierarchical hydroxide/bio-carbon as a better electrode for high-energy–density electrochemical supercapacitors. [ABSTRACT FROM AUTHOR]

Semiconductor-based photocatalyst serves as an attractive candidate for harnessing solar energy to generate renewable hydrogen via water splitting. Here, a novel Au/SrTiO 3 /TiO 2 (T3) photocatalyst of 3D SrTiO 3 /TiO 2 hollow nanosphere decorated by plasmonic Au nanoparticle (NP) is precisely constructed via an in-situ growth of cubic SrTiO 3 on anatase TiO 2 hollow nanospheres. By carefully regulating the SrTiO 3 /TiO 2 interface structure, the optimized Au/SrTiO 3 /TiO 2 (T3) photocatalyst achieves a remarkable photocatalytic H 2 evolution rate of 327.8 μmol g−1 h−1 without Pt as cocatalyst. Specifically, spectroscopic analyses and characterization results comprehensively prove that the favorable plasma electric field (Au) and the internal electric field (SrTiO 3 /TiO 2 heterojunction) coupled with the 3D electron transfer channel in 3D Au-SrTiO 3 /TiO 2 hollow nanospheres synergistically promote the interfacial charge separation and accelerate the interfacial transfer of charge carriers for efficient solar-driven photocatalytic H 2 evolution. This work presents a new strategy for the rational design of plasmonic metal functionalized 3D heterojunction photocatalysts for highly efficient solar-to-chemical energy conversion. [Display omitted] • Au-SrTiO 3 /TiO 2 hollow nanospheres are prepared for photocatalytic water splitting. • 3D hollow sphere unit structure provides electron transfer channels. • The plasma effect and internal electric field promote charge separation and transfer. • Au/SrTiO 3 /TiO 2 photocatalyst achieved a remarkable photocatalytic H 2 evolution. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hierarchical NiC 2 O 4 /Ni(OH) 2 nanospheres are synthesized via a simple two-step hydrothermal method as the positive electrode. • The porous biomass-derived carbon with the honeycomb structure is obtained from pine petals as the negative electrode. • Hierarchical NiC 2 O 4 /Ni(OH) 2 nanospheres and the porous biomass-derived carbon possess a high specific capacity. • The hybrid supercapacitor exhibits excellent energy and power density. The high-performance hybrid supercapacitor (HSC) with high power capability and stable cyclability is intensively pursued as a next-generation energy storage device. Here, a kind of hierarchical NiC 2 O 4 /Ni(OH) 2 nanospheres, consisting of subunits of NiC 2 O 4 nanorods and Ni(OH) 2 nanospheres, are synthesized via a two-step hydrothermal method. The hierarchical NiC 2 O 4 /Ni(OH) 2 nanosphere positive electrode, benefiting from the synergistic effect of unique hierarchical structure and built-in electric fields, significantly boosting electron transmission capability and accelerating the ion/electron transfer rate, delivers an excellent specific capacity of 668 C g−1 at 1 A g−1. In addition, the porous biomass-derived carbon (PBC) with the honeycomb structure from pine petals as the negative electrode shows a remarkable electrochemical performance, exhibiting a specific capacitance of 249.7 F g−1 at 1 A g−1. As such, an assembled HSC of NiC 2 O 4 /Ni(OH) 2 ||PBC based on hierarchical NiC 2 O 4 /Ni(OH) 2 nanospheres positive electrode and PBC negative electrode display a conspicuous energy density of 31.07 Wh kg−1, and a power density of 833.47 W kg−1 at a maximum potential window of 1.7 V. This innovative hierarchical engineering of double nickel-based composites with bio-carbon provides an advanced enlightenment for high-performance HSCs. [ABSTRACT FROM AUTHOR]

• Co 3 V 2 O 8 -T (T = temperature/°C) are prepared as bifunctional electrocatalysts. • Co 3 V 2 O 8 -400 nanofibers show small Tafel slopes of 43 and 63 mV dec−1 for ORR and OER. • The Co 3 V 2 O 8 -400 nanofiber has the best catalytic activities for ORR and OER. • The mechanism of Co 3 V 2 O 8 -400 nanofiber is simulated by DFT. Highly active and stable bifunctional electrocatalysts towards oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are necessary for practical fuel cells, metal-air batteries, and water splitting. Herein, we report a series of bifunctional Co 3 V 2 O 8 -T (T = temperature/°C) electrocatalysts by using Co-carbon electrospun nanofiber as a template, followed by a one-step calcination process. As expected, the developed Co 3 V 2 O 8 -400 nanofiber electrocatalyst shows a very small Tafel slope of 43 and 63 mV dec−1 for the ORR and OER in the alkaline solution, respectively. In addition, density functional theory (DFT) calculations reveal that the metallic conductivity and interface V-Co interaction of Co 3 V 2 O 8 -400 nanofiber boost ORR and OER electrocatalytic reactions. [ABSTRACT FROM AUTHOR]