Constructing hollow nanorod arrays by nickel–cobalt phosphide nanosheets as high-performance electrocatalysts for urea-assisted energy-efficient hydrogen generation

The slow kinetics of oxygen evolution reaction (OER) severely limits electrocatalytic water cracking for hydrogen (H2) generation. Replacing sluggish OER with thermodynamically favorable urea oxidation reaction holds great promise for energy-efficient H2 generation while also addressing the issue of urea-rich water contamination. In this paper, novel hollow nanorod arrays made of NiCoP nanosheets (denoted as NiCoP [email protected]) are created using an environmentally friendly and simple template-assisted electrodeposition and subsequent phosphorization method. The distinct HNRAs enable fast transport and short diffusion paths for electroactive species, as well as the high catalysts availability. Because of these structural advantages, NiCoP [email protected] have excellent electrocatalyst activity, requiring only a potential of 1.35 V (vs. RHE) to achieve a current density of 50 mA cm−2 with robust durability. Furthermore, an overall urea electrolysis system is constructed using commercial Pt/C as the cathode and NiCoP [email protected] as the anode, with an outstanding activity of 1.43 V and excellent stability at 50 mA cm−2. This paper presents a novel structural strategy for designing an electrocatalyst for urea-assisted energy-efficient H2 generation.