Mixed silver-nickel oxide AgNiO₂: Probing by CO during XPS study

In this work, the reaction properties of mixed silver-nickel oxide AgNiO₂ were investigated in the reaction of CO oxidation ranging from room temperature up to 350 °C. X-ray photoelectron spectroscopy revealed the presence of a single oxidized silver state and the combination of Ni²⁺ and Ni³⁺ species on the surface of the as-prepared mixed oxide. It was established that AgNiO₂ was able to interact with CO at room temperature. It was accompanied by the simultaneous titration of the lattice (O^2--like) and weakly charged (O^--like) oxygen species. The interaction with CO below 100 °C resulted in the accumulation of carbonate-like species on the AgNiO₂ surface. Above 150 °C, the surface structure of mixed oxide was found to be disrupted, resulting in the formation of individual particles of metallic silver and oxidized nickel.