XAFS study on the impact of local structure on electrochemical performance for Co3O4 nanowire arrays

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 Co3O4 nanowire arrays due to the interaction between the phases of Co3O4 and Co-2(OH)(2)CO3. Comparing to pure Co3O4 nanowire arrays, the mixed phase sample is richer in Co2+ 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 Co3O4 nanowire arrays with abundant Co2+ sites provide more redox centres in electrochemical reaction than the pure Co3O4 nanowire arrays.