The synthesis of γ-MnOOH nanorods as an efficient electrocatalyst for urea oxidation

In this study, γ-MnOOH nanorods synthesized by polysaccharide- assisted hydrothermal method as an efficient electrocatalyst for urea oxidation. The γ-MnOOH structure and morphology are confirmed by X-ray diffraction and scanning electron microscopy (SEM). The γ-MnOOH material, which contains hydroxyl groups and has an average oxidation state of Mn of three as demonstrated by XPS, exhibits excellent electrocatalytic activity towards urea oxidation reaction (UOR) compared to bare nickel foam (NF). Specifically, the overpotential at 10 mA/cm2 for γ-MnOOH is found to be 1.05 V, which is significantly lower than that of the NF (i.e., 1.12 V). Notably, the UOR over γ-MnOOH has a potential that is 180 mV lower than observed during the oxygen evolution reaction (OER) using the same electrode. These findings suggest that the γ-MnOOH nanorods could serve as a promising electro-catalyst for UOR in various energy storage and conversion applications.