Dong Shihui, Li Bin, Cui Xuefeng, Tan Shijing, Wang Bing
Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics , University of Science and Technology of China , Hefei , Anhui 230026 , China.
J Phys Chem Lett. 2019 Aug 15;10(16):4683-4691. doi: 10.1021/acs.jpclett.9b01527. Epub 2019 Aug 6.
When a metal single-atom (SA) catalyst is supported on a semiconducting photocatalyst, the charge transfer of the photoexcited carriers to metal SAs can provide a synergetic activity for the co-catalysts. Here, we report the interfacial electronic coupling of the Au SAs on the TiO(110) surface using scanning tunneling microscopy/spectroscopy, in combination with first-principles calculations. Distinct energy and spatial distributions of the metal-induced gap states (MIGSs) are experimentally revealed for the Au SAs adsorbed at the terminal Ti sites and the oxygen vacancies. The localized MIGS below the Fermi level provides a dedicated channel for the transfer of a photoexcited hole from the TiO substrate to the adsorbed Au SAs. The hole can weaken the Ti-Au bonding and activate the diffusion of Au SAs. Our results shed light on combining the advantages of photocatalysis and metal SA catalysis using a co-catalyst, which is promising to promote chemical reactions at low temperatures.
当金属单原子（SA）催化剂负载在半导体光催化剂上时，光激发载流子向金属单原子的电荷转移可为助催化剂提供协同活性。在此，我们结合第一性原理计算，利用扫描隧道显微镜/光谱法报道了TiO(110)表面上金单原子的界面电子耦合。实验揭示了吸附在末端Ti位点和氧空位处的金单原子的金属诱导能隙态（MIGS）具有不同的能量和空间分布。费米能级以下的局域化MIGS为光激发空穴从TiO衬底转移到吸附的金单原子提供了一个专用通道。空穴会削弱Ti-Au键并激活金单原子的扩散。我们的结果揭示了利用助催化剂结合光催化和金属单原子催化的优势，这有望促进低温下的化学反应。
