Photoelectrocatalytic performance of a titania-keggin type polyoxometalate-gold nanocomposite modified electrode in methanol oxidation

摘要

Aminosilicate sol-gel supported titania-keggin type polyoxometalate-gold nanocomposite materials (APS/(P25-PTA-Au)_(NCM)) (APS, (3-aminopropyl)triethoxysilane; P25, Degussa-TiO_2; PTA, Na _3PW_(12)O_(40)?xH_2O) were prepared by a simple chemical reduction method and characterized by diffuse reflectance spectroscopy, photoluminescence, x-ray diffraction, transmission electron microscopy and energy-dispersive x-ray analysis. The as-prepared APS/(P25-PTA-Au)_(NCM) was used to fabricate the photoelectrode for a photoelectrochemical cell. The photoelectrocatalytic activity of the APS/(P25-PTA-Au)_(NCM) modified photoelectrode in methanol oxidation was investigated. The APS/(P25-PTA-Au)_(NCM) modified photoelectrode showed a higher photocurrent for methanol oxidation than control photoelectrodes. The modification of titania using PTA and Au nanoparticles significantly boosted the photoelectrocatalytic performance by a synergistic effect and thus improved the interfacial charge transfer processes. The presence of Au nanoparticles enhances the interfacial electron transfer process. The APS silicate sol-gel matrix acts as a very good support material for the preparation of the nanocomposite material and for preparation of the chemically modified electrode. This newly fabricated APS/(P25-PTA-Au)_(NCM) modified photoelectrode could be a promising candidate for photoelectrochemical cells.