Voltammetry study of electrocatalytic activity of lanthanum nickel perovskite nanoclusters-based composite catalyst for effective oxidation of urea in alkaline medium

Abstract

Effective electrooxidation of urea has been the focus of research and development for energy and environmental applications. A modified glassy carbon (GC) electrode with two successive layers of conducting poly(aniline) (PANI) and lanthanum nickel oxide (LNO)-graphene oxide (GO) mixture was fabricated for urea electrooxidation in alkaline medium. Different conditions of catalyst preparation were examined for optimum electrocatalytic activity towards urea oxidation. GO improved the response and is considered advantageous support for the perovskite due to its structural and electronic differences compared to graphene (G). The highest electrocatalytic activity observed was for non-calcinated perovskite catalyst prepared by citric acid fuel and physically mixed with GO in the ratio (1:2). The use of La2NiO4 perovskite is beneficial with relatively low weight percentage of Ni (14.6 %) compared to other Ni-based catalysts for electrooxidation of urea. The perovskite catalyst is synthesized using microwave-assisted method that reduces chemicals usage and energy consumption. The non-calcinated perovskite catalyst and the (PANI/LNO-GO) composite were characterized by X-ray diffraction (XRD) and scanning electron microscopy/energy dispersive analysis (SEM-EDAX). The composite is applicable in temperature range (10 °C up to 50 °C), and at different urea concentrations from 0.1 M to 1.0 M in basic (KOH) electrolyte.