Single Atom Ru Doped Ni₂P/Fe₃P Heterostructure for Boosting Hydrogen Evolution for Water Splitting

Abstract

Modulating the chemical composition and structure has been considered as one of the most promising strategies for developing high-efficient water splitting catalysts. Here, a single-atom Ru doped Ni₂P/Fe₃P catalyst is synthesized by introducing the dispersed Ru atoms to adjust Ni₂P/Fe₃P heterostructure. Single atom Ru provides effective hydrogen evolution reaction (HER) active sites for boosting catalytic activities. The catalyst with only 0.2 wt.% content of Ru exhibits an overpotential of 19.3 mV at 10 mA cm^-2, which is obviously lower than 146.1 mV of Ni₂P/Fe₃P. Notably, an alkaline overall water electrolyzer based on Ru-Ni₂P/Fe₃P catalysts achieves a cell voltage of 1.47 V and operates over 600 h at 10 mA cm^-2, which is superior to that of benchmark RuO₂//Pt/C (1.61 V). The theoretical calculations further confirm that Ru single atom doping can effectively optimize the hydrogen/water adsorption free energy of the active site and therefore improve the HER activity of heterostructure. This work provides a valuable reference to design high-activity and durability catalyst for water splitting through the double modulation of interface-effect and atomic doping.