Layered sphere-shaped TiO2 capped with gold nanoparticles on structural defects and their catalysis of formaldehyde oxidation
Chunyan Ma , Guanglong Pang , Guangzhi He , Yang Li , Chi He
,
Zhengping Hao
DOI:10.1016/j.jes.2015.12.004
Received July 24, 2015,Revised December 03, 2015, Accepted December 10, 2015, Available online December 30, 2015
Volume 28,2016,Pages 77-85
We describe here a one-step method for the synthesis of Au/TiO2 nanosphere materials, which were formed by layered deposition of multiple anatase TiO2 nanosheets. The Au nanoparticles were stabilized by structural defects in each TiO2 nanosheet, including crystal steps and edges, thereby fixing the Au–TiO2 perimeter interface. Reactant transfer occurred along the gaps between these TiO2 nanosheet layers and in contact with catalytically active sites at the Au–TiO2 interface. The doped Au induced the formation of oxygen vacancies in the Au–TiO2 interface. Such vacancies are essential for generating active oxygen species (*O−) on the TiO2 surface and Ti3 + ions in bulk TiO2. These ions can then form Ti3 +–O−–Ti4 + species, which are known to enhance the catalytic activity of formaldehyde (HCHO) oxidation. These studies on structural and oxygen vacancy defects in Au/TiO2 samples provide a theoretical foundation for the catalytic mechanism of HCHO oxidation on oxide-supported Au materials.
