Coverage Dependence of Methanol Dissociation on TiO2(110).
Although the photochemistry of methanol on TiO2(110) has been widely investigated as a prototypical model of the photocatalytic reaction of organic molecules, the most fundamental question of the adsorption state of methanol on TiO2(110) is still unclear. We have investigated the adsorption of methanol on TiO2(110) using sum frequency generation vibrational spectroscopy (SFG-VS) and density functional theory (DFT) calculations. The SFG results indicate the dissociation of methanol is highly dependent on the coverage. The DFT calculations suggest that the methanol prefers the partially dissociated structure at low coverage, whereas the second layer methanol, which is hydrogen-bonded to the bridge-bonded oxygen site, largely blocks the dissociation of the first layer methanol. Our results not only resolves a long-standing debate regarding the adsorption state of methanol on TiO2(110) but also provides a detailed insight into the adsorption structure and sheds light on the photochemistry on this surface at the molecular level.
†International Center for Quantum Materials (ICQM) and School of Physics, Peking University, Beijing 100871, P. R. China.|∥Collaborative Innovation Center of Quantum Matter, Beijing 100871, P. R. China.
Shuo
S
Liu
†International Center for Quantum Materials (ICQM) and School of Physics, Peking University, Beijing 100871, P. R. China.|∥Collaborative Innovation Center of Quantum Matter, Beijing 100871, P. R. China.
An-An
AA
Liu
†International Center for Quantum Materials (ICQM) and School of Physics, Peking University, Beijing 100871, P. R. China.|‡Beijing Computational Science Research Center, Beijing 100094, P. R. China.
Bo
B
Wen
†International Center for Quantum Materials (ICQM) and School of Physics, Peking University, Beijing 100871, P. R. China.|∥Collaborative Innovation Center of Quantum Matter, Beijing 100871, P. R. China.
Ruidan
R
Zhang
§State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, Liaoning, P. R. China.
Chuanyao
C
Zhou
‡Beijing Computational Science Research Center, Beijing 100094, P. R. China.
Li-Min
LM
Liu
†International Center for Quantum Materials (ICQM) and School of Physics, Peking University, Beijing 100871, P. R. China.|∥Collaborative Innovation Center of Quantum Matter, Beijing 100871, P. R. China.
Zefeng
Z
Ren
Aqueous Interface; Catalysis; Partial Dissociation; Photocatalysis; Sum Frequency Generation; Transition-metal Oxide; Vibrational Spectroscopy