Physical Chemistry Seminar, Dr. Xueming Yang( Dalian Institute of Chemical Physics)

December 06, 2017 - 12:00 PM - 01:00 PM
Speaker: 
Host: Lester
Location: 
Carol Lynch Lecture Hall Chemistry Complex

Surface Photocatalysis of Methanol and Water at Single Molecule Level 

  

Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Department of Chemical Physics, University of Science and Technology of China

 

Abstract

Heterogeneous photocatalysis is an important area of research and has received great attentions from chemists, physicists as well as material scientists because of its potential applications in energy and environmental science and technology. For many years, surface photocatalysis was predominantly viewed as an electron or hole driven event. However, the detailed physical picture of how a specific surface photocatalytic reaction takes place remains unclear. During the last few years, we have developed a series of new experimental tools (2PPE, TOF-TPD and STM) in our laboratory in efforts to study photocatalysis of methanol and water on TiO2(110) under well defined experimental conditions, and try to understand the elementary chemical reaction processes of photocatalysis of methanol and water on TiO2. Using these techniques in combination with laser-surface photocatalysis, we have observed elementary chemical reaction processes of photocatalysis of methanol and water on TiO2(110). We have shown clearly the methanol photocatalysis on TiO2(110) proceeds in a number elementary steps, that can be understood using a ground state reaction picture. Photocatalytic reaction intermediate of methanol photocatalysis on TiO2(110) has also been observed using high resolution STM at a single molecule level. In addition, strong photon energy effect on photocatalysis of both methanol and water has been observed. Experimental results also show that photocatalytic dissociation of water behaves very differently from methanol photocatalysis. These results cannot be explained by the widely accepted photocatalysis model based on electron or hole driven chemistry, suggesting that dynamics on surface is a crucial issue in photocatalysis. A dynamics based model for photocatalysis is proposed to explain these new experimental observations.

 

References:

1) Q. Guo, C. Xu, Z. Ren, W. Yang, Z. Ma, D. Dai, H. Fan, T. Minton and X. Yang,J. Am. Chem. Soc. 134, 13366 (2012).

2) C. Xu, W. Yang, Z. Ren, D. Dai, Q. Guo, T. Minton and X. Yang, J. Am. Chem. Soc. 135, 19039 (2013).

3) W. Yang, D. Wei, X. Jin, C. Xu, Z. Geng, Q. Guo, Z. Ma, D. Dai, H. Fan and X. Yang, J. Phys. Chem. Lett. 7, 603 (2016).

4) Q. Guo, C. Zhou, Z. Ma, Z. Ren, H. Fan and X. Yang, Chem. Soc. Rev. 45 3701-3730 (2016).

 

inquires please contact Rosa M. Vargas rvargas@sas.upenn. edu

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