An efficient and stable MnCo@NiS catalyst for oxygen evolution reaction constructed by a step-by-step electrodeposition way

Abstract

The oxygen evolution reaction (OER) is vital for water electrolysis which demands low-cost, durable, and efficient electrocatalysts. Recently, 3d transition metal based OER catalysts become very attractive due to their abundant earth reserve and low price. However, these transition metals still suffer from severe dissolution problem and inappropriate adsorption ability to the intermediate species during OER catalysis. Herein, we prepared Mn and Co co-decorated Ni composites nanosheets (MnCo@NiS) via a facile step-by-step electrodeposition way, which showed near-optimal adsorption energy to oxygenated intermediates and much better electrocatalytic OER performance than single metal decorated NiS or non-decorated one, especially requiring a low OER overpotential of only 286 mV at 10 mA cm−2 in an alkaline electrolyte and Tafel slope of 31.5 mV dec−1. The results indicated Mn and Co co-decoration is very efficient way to change the electron distribution and optimize the adsorption energy of NiS, leading to the high OER performance. In particular, the MnCo@NiS electrode demonstrates a highly impressive stability with not only much less cation dissolution but negligible degradation after 20 h durability test at 50 mA cm−2.