Postdecorated Polyoxometalate Metal–Organic Framework-Constructed Ternary Electrocatalysts for Hydrogen Evolution

Abstract

Metal–organic frameworks (MOFs) are widely used as precursor materials for electrocatalysts in the hydrogen evolution reaction (HER) because of the various and adjustable metal sites with long-ranged order and porous structures. In this paper, polyoxometalate-based MOF (POMOF) ([Ni(H₂O)₂(bth)(Mo₈O₂₆)_0.5·3H₂O], JLJZ-1) was synthesized by ammonium molybdate hydrate, Ni²⁺, and a flexible chain ligand (bth, 1,6-bis(1,2,4-triazol-1-yl)hexane) via a hydrothermal method. Then, JLJZ-1 decorated with polyvinylpyrrolidone (PVP), phytic acid (PA) as the composite precursor, and carbon-coated ternary hydrogen evolution electrocatalyst (Mo₂C/MoP/MoNiP@C) was prepared via one-step calcination. In acidic medium, Mo₂C/MoP/MoNiP@C exhibits good catalytic activity with an overpotential of 154 mV at the current density of 10 mA cm^–2, and it shows good stability within 14 h. After characterization and tests, the satisfactory HER performance is mainly attributed to the synergistic effects among multiple components. Furthermore, the mesoporous structures help to expose more active sites, and the graphitic carbon layers protect the catalyst nanoparticles from corrosion. This work provides a guiding strategy of postdecorated POMOF-based composites as precursors for multicomponent electrocatalysts used in energy conversion fields.