Hierarchical Cu_(3)P-based nanoarrays on nickel foam as efficient electrocatalysts for overall water splitting

Exploring the efficient bifunctional catalysts and binder-free electrode materials for both oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)is receiving continuous interest.Herein,we report the fabrication of hierarchical copper phosphide nanoarrays(Cu_(3)P)on three-dimensional(3D)nickel foam(NF)through a template-directed synthetic strategy as electrocatalysts for overall water splitting.Specifically,the Cu_(3)P/NF electrode demonstrates a remarkably low overpotential of~331 m V to approach the current density of 50 m A cm^(-2)in the OER,and an overpotential of~115 m V to achieve-10 m A cm^(-2)current density in the HER.Meanwhile the Cu_(3)P/NF catalyst could hold a great stability for both reactions in alkaline condition,reflected in 37 h for OER and 24 h for HER of consistent galvanostatic electrolysis.As revealed by TEM,STEM and XPS characterizations,the high catalytic OER activity can be ascribed to the 3D open structure of Cu_(3)P/NF and the abundant Cu O active sites in hierarchical Cu O/Cu_(3)P/NF structure after in-situ activation.Furthermore,the overall water splitting is conducted in a two-electrode cell,which requires only a cell voltage of 1.63 V to approach 10 m A cm^(-2)with a good stability of 20 h.This protocol of Cu_(3)P/NF electrode affords a general strategy to construct hierarchically structured metal phosphides for clean energy-related application.