Ni2P/NiMoP heterostructure as a bifunctional electrocatalyst for energy-saving hydrogen production

Electrochemical water splitting is a sustainable and feasible strategy for hydrogen production but is hampered by the sluggish anodic oxygen evolution reaction (OER). Herein, an effective approach is introduced to significantly decrease the cell voltage by replacing the anodic OER with a urea oxidation reaction (UOR). A Ni2P/NiMoP nanosheet catalyst with a hierarchical architecture is uniformly grown on a nickel foam (NF) substrate through a simple hydrothermal and phosphorization method. The Ni2P/NiMoP achieves impressive HER activity, with a low overpotential of only 22 mV at 10 mA cm-2 and a low Tafel slope of 34.5 mV dec -1 . In addition, the oxidation voltage is significantly reduced from 1.49 V to 1.33 V after the introduction of 0.33 M urea. Notably, a two-electrode electrolyzer employing Ni2P/NiMoP as a bifunctional catalyst exhibits a current density of 10 mA cm-2 at a cell voltage of 1.35 V and excellent long-term durability after 80 h.

Automated summary

An effective approach is introduced in this study to replace the anodic oxygen evolution reaction with a urea oxidation reaction, significantly decreasing the cell voltage for hydrogen production. The Ni2P/NiMoP catalyst shows impressive activity for both hydrogen evolution and oxygen evolution during hydrogen production. The introduction of urea results in a significant reduction in oxidation voltage, and the two-electrode electrolyzer with Ni2P/NiMoP catalyst exhibits excellent long-term durability.