Vanadium Doped FeP Nanoflower with Optimized Electronic Structure for Efficient Hydrogen Evolution

Reasonable design of hydrogen evolution reaction (HER) electrocatalyst from the perspective of electronic structure is a vital way to optimize the catalytic activity. Mono-metallic iron-based phosphates have been shown to be active toward HER, but their performance remains unsatisfactory despite their abundant reserves and low preparation cost. Here, guided by the d-band center and band structure theories, V-doped FeP nano-flower grown directly on iron foam are constructed. Combining the density functional theory (DFT) simulations with physical characterizations reveal that the enhanced HER activity is mainly attributed to the lowed d-band central position, increased water dissociation capacity, decreased hydrogen formation energy barrier and reduced charge transfer impedance. As a HER catalyst in 1 M KOH, the obtained V-FeP shows low overpoten-tials of ~149, ~246 and ~290 mV to deliver the current densities of 100, 500 and 1000 mA cm(-2) with at least 24 h. When coupled with other highly active oxygen evolution reaction (OER) catalyst (NiFe-LDH/IF), the NiFe-LDH/IF(+) || V-FeP/IF(-) pair also performs a low cell voltage and over 100-h stability at high current density of 1000 mA cm(-2), which endows it a large potential in the practical electrolytic water industry. Our work may provide a reference for the enhancement of inert and low-cost HER-active iron phosphide. (C) 2022 Published by Elsevier Inc.