Metallic FePSe₃ nanoparticles anchored on N-doped carbon framework for All-pH hydrogen evolution reaction

The present nonprecious hydrogen evolution electrocatalysts deliver high activity either in acid or alkaline media, indicating the urgent demand for development of pH-universal catalysts. In this work, we report a high-performance electrcatalyst based on ternary iron phosphoselenide (FePSe₃) nanoparticles anchored on N-doped carbon framework for hydrogen evolution reaction (HER) in acidic, neutral and basic media. The FePSe₃ nanoparticles with metallic nature enable to fully utilize accessible edge sites, and the highly open yet interconnected three-dimensional framework creates large surface area, exposing abundant active sites and providing convenient charge/ionic diffusion pathway. DFT calculations reveal the synergistic electronic interaction between Se and P, leading to optimal electronic structures and hydrogen adsorption free energy on Fe, P and Se sites, thus facilitating HER kinetics. As a result, the obtained FePSe₃/NC exhibits superior HER activities with low overpotentials of 70, 140.1 and 118.5 mV to afford 10 mA cm⁻² current density in acidic, neutral and basic media, as well as robust stability in all-pH range. This work highlights the dual-anion effect to radically construct all-pH HER electrocatalysts.