XPS and Voltammetry Stuides of Redox Behavior of LaCr_(1-x)Ni_xO_3 electrodes

摘要

An in-situ XPS and voltammetry investigation of the redox properties of LACr_(1-x)NI_xO_3 was carried out by incorporating the matrials as one electrode in an electrochemical cell, which was directly mounted on a heated sample stage in an ultra high vacuum chamber. Under a 0.7V cathodic bias, the perovskites reduce from formal oxidation state of NI~(3+) to Ni~(2+). This reduction is accompanied by wholeasle shofts of the Cr and O core level binding energies, in keeping with the delocalized electronic states in the material. The adsorpton properties of the surfaces are affected by the redox state of the surfaces; increased CO_2 adsorption is observed on the reduced surface.