Selective Pt Deposition onto the Face (110) of TiO2 Assembled Microspheres That Substantially Enhances the Photocatalytic Properties

This work reports on a two-stage strategy toward the selective Pt deposition onto the face (110) of TiO2 assembled microspheres for excellent photocatalytic activities. This approach includes the assembly of nanowires with exposed faces (110) and tips (001) to form microspheres, which is followed by Pt deposition onto the face (110) under photoreduction. Systematic sample characterizations indicate that there exist abundant microcavities in between the roughly parallel nanowires of the microspheres which act as the microcapacitors for electronic storage, while Pt deposition featured by surface plasmon resonance under irradiation may function to donate or accept electrons. Therefore, under ultraviolet-light irradiation, Pt deposition accelerated the electronic migration from the conduction band of the microspheres to Pt, while under visible-light irradiation, electrons from Pt nanoparticles would transfer to the conduction band of the microspheres with a simultaneous transfer of the compensable electrons from a donor in reaction solution to the deposited Pt nanoparticles. As a consequence, Pt deposition onto TiO2 assembled microspheres is proved to yield an excellent photocatalytic performance superior over that without Pt deposition under ultraviolet or visible light irradiation.