Mesoporous Mn-doped FeP: facile synthesis and enhanced electrocatalytic activity for hydrogen evolution in a wide pH range

Water electrolysis is a clean and effective strategy for mass production of hydrogen. Iron phosphide is a fascinating candidate for hydrogen evolution reaction (HER) among the reported Pt-free metal catalysts; however, the catalytic activity of FeP is far behind Pt. Herein, we prepared a highly efficient and durable mesoporous Mn-doped FeP (Mn-FeP) catalyst for HER via a facile and controllable synthesis route. It is manifested that Mn doping leads to improved electroactivity of mesoporous FeP in a wide pH range. For mesoporous Mn-FeP catalyst, the overpotential is 69, 157 and 173 mV in H2SO4, PBS and KOH electrolyte at 10 mA cm-2, respectively, which is 21, 40 and 54 mV less than that of its counterpart mesoporous FeP. Furthermore, it can be concluded that the enhanced HER activity of Mn-FeP is ascribed to both the appropriate thermo-neutral hydrogen adsorption free energy and the accessible active sites thanks to the mesoporous structure from the density functional theory (DFT) calculation and the exper...