Liu Changping, Lin Le, Wu Hao, Liu Yijing, Mu Rentao, Fu Qiang
State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Phys Chem Chem Phys. 2023 Jul 26;25(29):20121-20127. doi: 10.1039/d3cp02580b.
Tuning an oxide/metal interface is of critical importance for the performance enhancement of many heterogeneous catalytic reactions. However, catalytic oxidation occurring at the interface between non-reducible oxide and metal has been challenging, since non-reducible oxides hardly lose their lattice oxygen (O) or dissociate O from the gas phase. In this work, a ZnO monolayer film on Au(111) is used as an inverse catalyst to investigate CO oxidation occurring at the ZnO/Au(111) interface high pressure scanning tunneling microscopy. Surface science experiments indicate that oxygen intercalation under the ZnO monolayer film, termed ZnO/O/Au(111), can be achieved a surface reaction with 1 × 10 mbar O. Subsequent exposure of the formed ZnO/O/Au(111) surface to mbar CO at room temperature leads to the recovery of the pristine ZnO/Au(111) surface. Theoretical calculations reveal that O adjacent to intercalated oxygen (O) is activated due to the O-Zn-O bonding and surface corrugation, which can be directly involved in CO oxidation. Subsequently, O migrates to the formed oxygen vacancy from the subsurface resuming the pristine ZnO structure. These results thus reveal that oxygen intercalation underneath single-layer ZnO will strongly boost the oxidation reaction activating adjacent lattice oxygen atoms.
调控氧化物/金属界面对于许多多相催化反应的性能提升至关重要。然而，在不可还原氧化物与金属的界面处发生催化氧化一直具有挑战性，因为不可还原氧化物几乎不会失去其晶格氧（O）或从气相中解离出O。在这项工作中，Au(111)上的ZnO单层膜被用作逆催化剂，通过高压扫描隧道显微镜研究在ZnO/Au(111)界面处发生的CO氧化。表面科学实验表明，在ZnO单层膜下的氧嵌入，即ZnO/O/Au(111)，可以通过与1×10毫巴O的表面反应实现。随后在室温下将形成的ZnO/O/Au(111)表面暴露于毫巴CO中会导致原始ZnO/Au(111)表面的恢复。理论计算表明，由于O-Zn-O键合和表面起伏，与嵌入氧（O）相邻的O被激活，这可以直接参与CO氧化。随后，O从次表面迁移到形成的氧空位，恢复原始的ZnO结构。因此，这些结果表明，单层ZnO下的氧嵌入将通过激活相邻的晶格氧原子有力地促进氧化反应。
