Novel urchin-like CoNiP as advanced pH-universal electrocatalysts toward hydrogen evolution reaction

Electronic structure and morphology modulation are challenging for the construction of efficient electrocatalysts towards water splitting. Herein, a facile hydrothermal strategy and subsequent phosphorization process are utilized to synthesize urchin-like CoNiP integrated by nanowires. The synthesized urchin-like CoNiP can be applied as electrocatalysts for hydrogen evolution reaction (HER) in alkaline, neutral, and acidic media. In particular, the optimal urchin-like CoNiP exhibits superior HER activity in alkaline electrolytes, with small overpotentials (157, 317, and 437 mV) at the current density 10, 100, and 200 mA cm(-2), respectively, and a small Tafel slope (49.6 mV dec(-1)) in 1 M KOH, which is comparable to that of Pt/C catalyst. Moreover, when urchin-like CoNiP is employed as both the cathode and anode in 1 M KOH, a low cell overpotential of 490 mV is required to reach the current density of 10 mA cm(-2), suggesting the efficient electrocatalyst toward overall water splitting. The superior performance of urchin-like CoNiP can be associated with the sharp-tip enhancement effect since the hierarchical structure composed of nanowires with high curvature tips benefits the accumulation of electrons on the tip of the nanowires to serve as effectively active sites for reactions and the mass transfer, as well as the fast electron transfer due to the good electrical conductivity of the bimetallic phosphide. This work opens up a promising approach to rationally construct low-cost and efficient electrocatalysts for water splitting.

Automated summary

The urchin-like CoNiP synthesized through a facile hydrothermal strategy and subsequent phosphorization process exhibits superior hydrogen evolution reaction (HER) activity, particularly in alkaline media. Its exceptional performance is attributed to the sharp-tip enhancement effect and excellent electrical conductivity, offering a promising approach for the rational construction of low-cost and efficient electrocatalysts for water splitting.