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Efforts to develop high-performance electrocatalysts for the hydrogen evolution reaction (HER) are of utmost importance in ensuring sustainable hydrogen production. The controllable fabrication of inexpensive, durable, and high-efficient HER catalysts still remains a great challenge. Herein, we introduce a universal strategy aiming to achieve rapid synthesis of highly active hydrogen evolution catalysts using a controllable hydrogen insertion method and solvothermal process. Hydrogen vanadium bronze HxV2O5 was obtained through controlling the ethanol reaction rate in the oxidization process of hydrogen peroxide. Subsequently, the intermetallic PtCoVO supported on two-dimensional graphitic carbon nitride (g-C3N4) nanosheets was prepared by a solvothermal method at the oil/water interface. In terms of HER performance, PtCoVO/g-C3N4 demonstrates superior characteristics compared to PtCo/g-C3N4 and PtCoV/g-C3N4. This superiority can be attributed to the notable influence of oxygen vacancies in HxV2O5 on the electrical properties of the catalyst. By adjusting the relative proportions of metal atoms in the PtCoVO/g-C3N4 nanomaterials, the PtCoVO/g-C3N4 nanocomposites show significant HER overpotential of η10 = 92 mV, a Tafel slope of 65.21 mV dec−1, and outstanding stability (a continuous test lasting 48 h). The nanoarchitecture of a g-C3N4-supported PtCoVO nanoalloy catalyst exhibits exceptional resistance to nanoparticle migration and corrosion, owing to the strong interaction between the metal nanoparticles and the g-C3N4 support. Pt, Co, and V simultaneous doping has been shown by Density Functional Theory (DFT) calculations to enhance the density of states (DOS) at the Fermi level. This augmentation leads to a higher charge density and a reduction in the adsorption energy of intermediates. [ABSTRACT FROM AUTHOR]

Highly efficient electrocatalysts for the hydrogen evolution reaction (HER) are essential for sustainable hydrogen energy. The controllable production of hydrogen energy by water decomposition depends heavily on the catalyst, and it is extremely important to seek sustainable and highly efficient water-splitting electrocatalysts for energy applications. Herein, bimetallic RuYO2−x nanoparticles (Ru: 8.84 at.% and Y: 13 at.%) with high densities and low loadings were synthesized and anchored on graphene through a simple solvothermal strategy by synthesizing hydrogen yttrium ketone (HxYO2−x) serving as an inserted medium. Electron microscopy demonstrated that the RuYO2−x/C was composed of densely arranged particles and graphene flakes. Electrochemical results showed that the RuYO2−x/C had a remarkably low overpotential of η10 = 56 mV at a current density of 10 mA cm−2 in alkaline media, a Tafel slope of 63.18 mV dec−1, and 24 h of stability. The oxygen vacancies of RuYO2−x/C provided a large proton storage capacity and a strong tendency to bind hydrogen atoms. DFT calculations showed that RuYO2−x/C catalysts with more Ru-O-Y bonds and VO dramatically decreased the energy barrier for breaking H-OH bonds. Moreover, the robust metal-support interactions provided optimized energies for hydrogen adsorption and desorption, which explained the high activity and favorable kinetics for RuYO2−x/C catalytic hydrogen precipitation in alkaline electrolyte reactions. This work presents a hydrogen insertion method for the preparation of low-loading, high-density, high-performance and stable water decomposition catalysts for hydrogen production. We present a strategy for significantly increasing the H contents on catalysts for the HER in alkaline electrolyte solutions, which were generated by combining ruthenium with HxYO2−x on an oxygen vacancy-rich graphene system. This strategy greatly increased the hydrogen coverage on the RuYO2−x/C catalyst to enhance the HER performance. [ABSTRACT FROM AUTHOR]

The design of high‐efficiency and cost‐effective electrocatalysts is one of the most crucial factors for facilitating the oxygen evolution reaction (OER). Therefore, we prepared CoxFe1‐xOOH with coral‐like nanonet arrays on carbon cloth (CC) as high‐performance OER catalysts by a facile hydrothermal method. The resulting CoxFe1‐xOOH was characterized by X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, and X‐ray photoelectron spectrometry. When serving as a catalyst electrode in the OER, Co0.875Fe0.125OOH/CC exhibits excellent catalytic activity. Co0.875Fe0.125OOH/CC has a low overpotential of 300 mV at a current density of 20 mA cm−2 (150 mV less than that of FeOOH/CC) and a small Tafel slope of 83 mV dec−1 in 1.0 M KOH in OER. Moreover, it also has a superior electrochemical durability for more than 50 h. [ABSTRACT FROM AUTHOR]

Developing high-performance, robust and cost-effective oxygen evolution reaction (OER) catalysts for electrochemical water splitting is a promising way to produce energy-saving electrolytic hydrogen fuels. Herein, a series of rational wire-in-plate nanostructured CoFe LDH electrocatalysts grown on a Ni foam were developed via a one-step hydrothermal method. In this series of catalysts, Co4Fe2-LDHs/Co(OH)2-NWs exhibit excellent OER performance which is attributed to the most rational wire-in-plate nanostructure: the overpotentials of only 220 and 231 mV to drive current densities of 50 mA cm−2 and 100 mA cm−2, respectively, with a small Tafel slope of 51 mV dec−1. Our study opens up a new horizon for the design of hierarchical structures with the coexistence of multidimensional nanounits for electrocatalysts. [ABSTRACT FROM AUTHOR]

Non-noble-metal electrocatalysts of transition metal phosphides have been considered as promising catalysts for hydrogen evolution reaction (HER); however, their bifunctional catalytic activities are limited by unsatisfactory performance in oxygen evolution reaction (OER). Here we report ultrathin amorphous CoFeP nanosheets derived from CoFe layered double hydroxides (LDHs) as bifunctional electrocatalysts with a simple phosphorization method. The partial phosphating induced by sodium hypophosphite can greatly reduce the thickness of nanosheets and promote the polycrystalline nature of the materials, leading to more active sites exposed and faster electronic transport. The optimal levels of phosphating agents are 1.8 g for OER and 2.4 g for HER, respectively, etched by which the resultant CoFeP materials can exhibit excellent electrocatalytic performances toward OER, HER and overall water splitting in alkaline media. At the current densities of 100 and 20 mA cm−2, ultralow overpotentials of 242 and 80 mV are achieved for OER and HER, individually, which are 128 mV lower than RuO 2 and 6 mV slightly lower than Pt, respectively. In a cell voltage of 1.62 V, the CoFeP materials reacted with 1.8 and 2.4 g phosphating agents and used as the anode and the cathode, respectively, can achieve 100 mA cm−2 current density and exhibit extraordinary durability for 30 h in overall water splitting. These superior electrocatalytic properties of ultrathin amorphous CoFeP nanosheets are comparable to those of state-of-the-art noble metal and other reported catalysts for OER, HER and overall water splitting. This work proposes a promising strategy for excellent bifunctional electrocatalysts by tailoring the morphology and crystallinity degree based on LDHs through a facile partial phosphating method. Partial phosphating was applied to synthesize ultrathin amorphous CoFeP nanosheets as bifunctional electrocatalyst with ultralow potential at high current density. Image 1 [ABSTRACT FROM AUTHOR]

This paper synthesized a novel Ag 3 PO 4 /P-g-C 3 N 4 via a two-step chemical route i.e. microwave-assisted heating and ion-exchange procedures. The as-synthesized hybrid presented high efficiency for photocatalytic hydrogen production. Systematic investigation indicated that phosphorus was successfully doped into the g-C 3 N 4 framework through microwave heating the mixture of melamine and NH 4 H 2 PO 4 for 40 min, which increases the BET surface area, broadens the visible light response region, and elevates the separation efficiency of electron-hole pairs. The Ag 3 PO 4 nanoparticles were decorated on the optimal P-g-C 3 N 4 sample via an ion-exchange process. Due to the instability of Ag 3 PO 4 , the formed composite is actually Ag/Ag 3 PO 4 /P-g-C 3 N 4 photocatalyst. The introduced Ag 3 PO 4 nanoparticles further improves the charge separation efficiency of P-g-C 3 N 4 , but slightly affects the surface area and optical property, which highlights the key role of the separation efficiency of electron-hole pairs in photocatalytic reaction. The best Ag 3 PO 4 /P-g-C 3 N 4 hybrid shows a photocatalytic H 2 production rate of 1221 and 90.2 μmol g−1 h−1 under simulated sunlight and visible light, respectively. This value is 2.1 and 1.4 times greater than that of g-C 3 N 4 and P-g-C 3 N 4 , respectively. Meanwhile, the Ag 3 PO 4 /P-g-C 3 N 4 displayed high photocatalytic stability. A probable photocatalytic mechanism of the hybrid was also suggested. Image 1 • Ag 3 PO 4 /P-g-C 3 N 4 was prepared via a combination of microwave-assisted heating and ion-exchange processes. • Ag 3 PO 4 /P-g-C 3 N 4 presented much better performance in photocatalytic H 2 evolution than g-C 3 N 4. • The high performance was mainly ascribed to the improved charge separation in the bulk and surface of g-C 3 N 4. • Z-scheme mechanism worked in the Ag 3 PO 4 /P-g-C 3 N 4 composite. [ABSTRACT FROM AUTHOR]

Water electrolysis powered by renewable energy is regarded as the feasible route for the production of hydrogen, which was obtained at the cathode side through electrochemical hydrogen evolution reaction (HER). Herein, we proposed a novel strategy to achieve high and stable HER catalytic performance by designing graphene coatings shaped like a flower trimetallic PtCoYO x @G nanoparticles with multiple petals and by adjusting the composition ratio of PtCoYO x @G (0.1:0.05:0.1). Compared with the bimetallic PtYO@G catalysts, the trimetallic PtCoYO x @G catalysts showed superior HER performance with an overpotential of 106 mV at 10 mA cm−2, a Tafel slope of 38.08 mV dec−1, and long-term stability of 25 h. Electron paramagnetic resonance (EPR) tests exhibited strong signal peaks and aerobic vacancies in PtCoYO x @G materials. Density functional theory (DFT) calculation revealed that Co doping increased the active site of the catalyst, resulting in excellent charge density with good conductivity. Therefore, the doping of Co in trimetallic PtCoYO x @G was the key to improve HER catalytic activity. [Display omitted] • PtCoYO x @G nanoparticles shaped like multiple petals were coated by graphene layers. • The trimetallic PtCoYO x @G catalysts showed superior HER performance with an overpotential of 106 mV at 10 mA cm−2 and long-term stability of 25 h. • DFT calculations revealed that Co doping increased the active site, resulting in excellent charge density with good conductivity. [ABSTRACT FROM AUTHOR]