Melamine intercalation approach for the synthesis of C, N codoped net-like NiCo oxides composites and Its Application towards oxygen evolution reaction in alkaline solution

Abstract

Electrolysis of water is a leading hydrogen production pathway with the advantages of simple technology, mature development and small environmental impact. However, the energy conversion efficiency seriously decreased due to the high overpotential produced by oxygen evolution reaction (OER). To decrease the overpotential of OER, NiCoOx particles with small sizes embedded in layered structure constituted with carbon and nitrogen composites (NiCoOx-CN) were prepared through melamine intercalation method with acetylacetonate as cobalt and nickel source. Finally, NiCoOx-CN showed excellent OER performance with an overpotential of only 326 mV to obtain current density of 10 mA cm−2 and Tafel slope of 70.8 mV·dec−1. Besides, NiCoOx-CN possessed excellent long-term durability in alkaline environments. Scanning electron microscopy (SEM), electron paramagnetic resonance (EPR) and other techniques were implemented to study the mechanism for the increased OER performance of NiCoOx-CN. The microstructure of NiCoOx-CN that the nanoparticles embedded into the interlinked layered nanosheets was helpful to expose more active sites. Meanwhile, the doping of C and N heteroatom and abundant oxygen vacancies also led to the enhanced conductivity of NiCoOx-CN and the optimized the electron transfer. Thus, the OER performance of NiCoOx-CN significantly boosted. As a result, this strategy holds great promise in preparing other high performance OER electrocatalysts with melamine.