Co-Cu-P nanosheet-based open architecture for high-performance oxygen evolution reaction

Abstract

The exploration of earth-abundant electrocatalysts and insight on the relationship between their activity and structure is challenging for large-scale electrochemical water oxidation. Herein, 2D Co-Cu-P nanosheets on Ni foam are fabricated by electrodeposition and subsequent phosphorization process. The Co-Cu-P nanosheets are highly interconnected to form an open-structured hierarchical network structure, which endows the product large surface area, efficient mass transportation, and fast gas releasing. In addition, the surface of Co-Cu-P would rapidly convert into hydroxides layer in the earlier oxygen evolution reaction (OER) process, which preserves the Co-Cu-P phosphide inside and serves as the real active sites for OER process. Benefiting from the rationally designed open-structured hierarchical network and the synergistic effect from the two kinds of metal cations with high conductivity, the resultant Co-Cu-P bimetal phosphide open-structured network delivers superb OER performance with an overpotential of 240 mV to drive a current density of 10 mA cm−2 in alkaline medium, outperforming the performance of the Co-P and Cu3P monometallic phosphide counterpart. This work provides a simple synthesis approach to construct bimetal phosphide with a rationally designed open-structured hierarchical network toward boosting electrocatalytic OER performance. The open-structured hierarchical Co-Cu-P/NF network would serve as a robust catalyst for electrochemical water oxidation. The remarkable OER electrocatalytic performance of Co-Cu-P/NF can be mainly attributed to the large surface area, efficient mass transportation and fast gas releasing, as well as the metallic character of Co-Cu-P/NF with a high conductivity.