Successive Anion/Cation Exchange Enables the Fabrication of Hollow CuCo<sub>2</sub>S<sub>4</sub> Nanorods for Advanced Oxygen Evolution Reaction Electrocatalysis
Qing Wang, Hui Xu, Xingyue Qian, Bingji Huang, Kun Wang, Lei Jin, Guangyu He, Haiqun Chen
Abstract
Hollow CuCo2S4 nanorods (H-CCS-Ns) have been successfully developed via a facile successive anion/cation-exchange method. The outstanding electrocatalytic performance of H-CCS-Ns is mainly attributed to its distinctive hollow structure, which accelerates the electron transfer rate and provides abundant active sites. Moreover, a mechanism study indicates that H-CCS-Ns has highly active octahedral Co3+, and the existence of Co3+ cations optimizes the adsorption of oxygen-involved intermediates, making H-CCS-Ns a promising OER electrocatalyst. Optimized H-CCS-Ns only need an ultralow overpotential of 220 mV to drive a current density of 10 mA·cm–2 and exhibit distinguished cycling stability with a negligible fluctuation for 30 h. More impressively, when H-CCS-Ns are assembled with Pt/C for overall water splitting, a voltage as low as 1.545 V is required at a current density of 10 mA·cm–2, and the catalyst shows outstanding stability for as long as 38 h. This study offers a feasible strategy to design hollow spinel catalysts for efficient OER catalysis.