Hierarchical Al-CoP/Ni2P heterostructure for alkaline hydrogen evolution reaction

Abstract

Developing low-cost and high-performance catalysts instead of Pt-based noble metal materials for alkaline HER is essential for sustainable clean technologies. However, the high energy barriers of H₂O dissociation and intermediate *H lead to the low efficiency and the difficultly of the alkaline HER. Herein, the hierarchical Al-CoP/Ni₂P on Ni foam (Al-CoP/Ni₂P@NF) was successfully prepared using interface and doping engineering strategies. The heterostructure, Al doping, and hierarchical morphology significantly improve the electronic configuration and the active surface area of the compound. Notably, the Al-doping compound exhibits excellent HER performance in 1.0 M KOH, achieving a current density of 10 and 20 mA cm⁻² at 55 and 72 mV overpotential, respectively, with a Tafel slope of 55.6 mV dec⁻¹. As an overpotential of 72 mV is performed, the current density 20 mA cm⁻² keeps unchanged for even 24 h in alkaline water electrolysis. DFT calculations further reveal that Al-induced partial electron redistribution of CoP/Ni₂P, thereby optimizing ΔG_H* and reducing the energy barriers of H₂O dissociation.