XAFS study on the impact of local structure on electrochemical performance for Co₃O₄nanowire arrays

Abstract

Abstract. Determining the local structure of catalyst materials is critical for understanding the mechanism of enhanced electrochemical activity in semiconductor electrode. Here, using X-ray absorption fine structure (XAFS) spectra, we reveal that the local disorder structure is formed for the mixed-phase Co 3 O 4 nanowire arrays due to the interaction between the phases of Co 3 O 4 and Co 2 (OH) 2 CO 3 . Comparing to pure Co 3 O 4 nanowire arrays, the mixed phase sample is richer in Co 2+ and the electronic structure is changed by the local structure, which are demonstrated by the X-ray absorption near-edge structure (XANES) spectra. It is deduced that the mixed-phase Co 3 O 4 nanowire arrays with abundant Co 2+ sites provide more redox centres in electrochemical reaction than the pure Co 3 O 4 nanowire arrays.