Ag-embedded MnO nanorod: facile synthesis and oxygen reduction

Abstract

Using manganese(II) acetate tetrahydrate and silver salts as precursors, heterostructured Ag@Ag_1.8Mn₈O₁₆ nanocomposites were obtained by in situ redox reaction at room temperature. The molar ratio of Ag⁺/Mn²⁺ was found to play an essential role in determining their morphology. At a molar ratio of 1 : 200, novel nanorod products with diameters of 10–20 nm and lengths of 280–800 nm were obtained. The nanorods were thermally unstable, with further calcination leading to pure MnO nanorods embedded with Ag as the final product, which was demonstrated by analysis of XRD, TEM, Raman spectroscopy and XPS. TG and TEM analysis were also considered to explore the influence of calcination temperature and the molar ratio on the crystalline structure and the morphology of the synthesized product. The novel nanorod exhibited improved performance in oxygen reduction reaction (ORR), indicating a cost-effective electrocatalyst.