Copper-Nickel Bimetallic Coordination Polymers as Precursors for New Cu-Ni Oxide Electrocatalyst for OER

Abstract

Electrocatalytic water splitting has received widespread attention due to the slow kinetics of the reaction and the complex electron transfer process, the oxygen evolution reaction (OER) occurring at the anode has become a major obstacle. The improved OER performance is attributed to the significant enhancement in accessible surface active sites and the decrease in charge transfer resistance. The exploration of efficient, cheap, and stable electrocatalysts for OER is of significant importance for energy conversion and storage. Currently, transition metal oxides (TMOs) show enormous potential as electrode materials for OER due to their low cost, redox chemistry, and high chemical stability. In this work, an impregnation method is demonstrated to synthesize Cu-based metal oxides doped with Ni (CuO, Cu_0.9Ni_0.1O, Cu_0.7Ni_0.3O, and Cu_0.5Ni_0.5O/NiO) as high-efficiency and low-energy electrocatalysts for the oxygen evolution reaction under alkaline conditions. This work combines the excellent catalytic efficiency of the transition metal with the large specific surface area and the substantial number of pores of the MOF. All materials show good overpotential values of 359, 352, 346, and 340 mV at a current density of 10 mA cm⁻². The Tafel slopes are 82.5, 47, 65, and 54 mV dec⁻¹, respectively, with very small attenuation for long-term catalytic reactions. Furthermore, the electrocatalysts showed short-term electrochemical stability for 12 h. Therefore, the present method opens a new path for the preparation of efficient and low-cost materials for application in OER.

Graphical Abstract