Interfacial Engineering of Heterostructured Co(OH)2/NiPx Nanosheets for Enhanced Oxygen Evolution Reaction

Abstract

AbstractThe oxygen evolution reaction (OER) remains a bottleneck for the overall water splitting. Electrocatalysts with superior activity and stability are still highly desired. Herein, a stepwise electrochemical strategy is developed to prepare Co(OH)2/NiPx nanosheet arrays with intimate and abundant heterostructures. The Co(OH)2 nanosheets, which are first electrodeposited on a blank carbon cloth electrode, serve as the substrate for the nucleation and growth of NiPx. The resultant heterointerfaces are well regulated by altering the loading of NiPx. The heterostructured Co(OH)2/NiPx with optimal NiPx loading demonstrate significantly enhanced conductivity and hydrophilicity, which greatly facilitate electron and mass transfer. In addition, strong electronic interaction between Co(OH)2 and NiPx is observed, favoring the generation of high‐valence cobalt center, thus the electrocatalytic performances toward OER are remarkably improved. The heterostructured Co(OH)2/NiPx nanosheets achieve the current density of 10 mA cm−2 at an overpotential of 236 mV, while the corresponding values for Co(OH)2 and the benchmark Ir/C are 292 and 262 mV, respectively. This study provides a facile and effective strategy to fabricate transition metal hydroxide/phosphide composite nanomaterials with intimate heterostructures, enhanced conductivity, and improved wettability, which opens a new direction for the design of highly active electrocatalysts.