Abstract
The electrocatalytic oxygen evolution reaction (OER) is the bottleneck to overall water splitting because of the slow kinetics of the four-electron transfer process. Therefore, it is of great significance to develop OER electrocatalysts with high activity, long durability, and scalability. Herein, we present a selenium-coated cobalt selenide (CoSe2@Se) catalyst that was first synthesized by in-situ growth on carbon cloth (CC) surface by hydrothermal method, followed by soaking treatment to prepare a three-dimensional coral-like Fe2O3-CoSe2@Se/CC composite. Electrochemical studies revealed that the optimized Fe2O3-CoSe2@Se/CC catalyst only requires 250 mV to reach 10 mA cm(-2) current density, yields a small Tafel slope (50.2 mV dec(-1)), and has good stability (10 mA cm(-2)@70 h) in the electrocatalytic OER process. The overall water splitting using Fe2O3-CoSe2@Se/CC as anode only requires 1.58 and 1.69 V to achieve 10 and 100 mA cm-2, respectively, much better than most previously reported catalysts. Analysis showed that the three-dimensional coral-like morphology exposing more active sites and the synergy between different species (giving rise to, inter alia, a favorable electronic structure that lowers the electrode overpotential) are the key to the observed improved electrocatalytic performance. This work provides a novel strategy for the rational design of nanostructured OER hybrid catalysts in the future.