An oxidized magnetic Au single atom on doped TiO2(110) becomes a high performance CO oxidation catalyst due to the charge effect

作者：Shi, J. L.; Zhao, X. J.; Zhang, L. Y.; Xue, X. L.; Guo, Z. X.; Gao, Y. F.; Li, S. F.^*

来源：Journal of Materials Chemistry A, 2017, 5(36): 19316-19322.

DOI：10.1039/c7ta05483a

• TITANIUM-DIOXIDE
• ROOM-TEMPERATURE
• SUPPORTED GOLD
• CLUSTERS
• RUTILE
• NANOPARTICLES
• OXIDE
• TIO2
• MECHANISM
• AU/TIO2

Catalysis using gold nanoparticles supported on oxides has been under extensive investigation for many important application processes. However, how to tune the charge state of a given Au species to perform a specific chemical reaction, e.g. CO oxidation, remains elusive. Here, using first-principles calculations, we show clearly that an intrinsically inert Au anion deposited on oxygen-deficient TiO2(110) (Au@TiO2(110)) can be tuned and optimized into a highly effective single atom catalyst (SAC), due to the depletion of the d-orbital by substrate doping. Particularly, Ni- and Cu-doped Au@TiO2 complexes undergo a reconstruction driven by one of the two dissociated O atoms upon CO oxidation. The remaining O atom heals the surface oxygen vacancy and results in a stable bow-shaped surface "O-Au-O" species; thereby the highly oxidized Au single atom now exhibits magnetism and dramatically enhanced activity and stability for O-2 activation and CO oxidation, due to the emergence of high density of states near the Fermi level. Based on further extensive calculations, we establish the "charge selection rule" for O-2 activation and CO oxidation on Au: the positively charged Au SAC is more active than its negatively charged counterpart for O-2 activation, and the more positively charged the Au, the more active it is.

• 出版日期2017-9-28
• 单位北京计算科学研究中心; 郑州大学