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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]

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]

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]

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]

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]

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]

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]