Intercalated PtCo Electrocatalyst of Vanadium Metal Oxide Increases Charge Density to Facilitate Hydrogen Evolution

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 H_xV₂O₅ 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 H_xV₂O₅ 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.