Deuterium Kinetic Isotope Effect in the Photocatalyzed Dissociation of Methanol on TiO2(110)

Wang, Tianjun1,2,7; Hao, Qunqing3; Wang, Zhiqiang4; Mao, Xinchun5; Ma, Zhibo2; Ren, Zefeng2; Dai, Dongxu2; Zhou, Chuanyao2; Yang, Xueming2,6

2018-11-22

10.1021/acs.jpcc.8b09077

Journal of Physical Chemistry C   影响因子和分区

1932-7447

Deuterium kinetic isotope effect (KIE) in the photochemistry of methanol on TiO2(110) has been studied to find the rate determining step (RDS) and understand the reaction mechanism using two-photon photoemission spectroscopy. Deuterium substitution of the methyl hydrogen has little effect on the kinetics of this reaction, suggesting that neither the break of the C-H(D) bond nor the transfer of the H(D) atoms to the bridging sites is the RDS in the transformation of methanol into formaldehyde. In contrast, the reaction rate of MeOH is similar to 1.3 times that of MeOD, suggesting that the cleavage of O-H(D) is the RDS in the photocatalyzed dissociation of methanol on TiO2(110). The results contradict the common fact that C-H(D) is more difficult to break than O-H(D) based on ground-state energetics, implying the involvement of photogenerated charge carriers in the reaction of the C-H breakage, whereas the cleavage of O-H is likely a thermal reaction. Difference in the activation energy of O-H and O-D dissociation reaction in the methanol/TiO2(110) system has been calculated based on the KIE measurements. Our work is consistent with the fact that methoxy is photocatalytically more reactive than methanol and suggests that the conversion of methanol into methoxy is crucial in the photochemistry of methanol on TiO2(110) and probably other metal oxide semiconductor surfaces.

SCI ; EI

英语

通讯

Strategic Pilot Science and Technology Project[XDB17000000]

Chemistry ; Science & Technology - Other Topics ; Materials Science

Chemistry, Physical ; Nanoscience & Nanotechnology ; Materials Science, Multidisciplinary

WOS:000451495600025

AMER CHEMICAL SOC

20184706084326

Activation energy ; Carrier mobility ; Deuterium ; Dissociation ; Ground state ; Kinetics ; Magnetic semiconductors ; Metals ; MOS devices ; Oxide semiconductors ; Photoelectron spectroscopy ; Reaction kinetics ; Titanium dioxide

Magnetic Materials:708.4 ; Semiconductor Devices and Integrated Circuits:714.2 ; Chemical Reactions:802.2 ; Organic Compounds:804.1 ; Inorganic Compounds:804.2 ; Classical Physics; Quantum Theory; Relativity:931

Web of Science

1.Chinese Acad Sci, Shanghai Adv Res Inst, 99 Haike Rd,Zhangjiang Hitech Pk, Shanghai 201210, Peoples R China
2.Chinese Acad Sci, Dalian Inst Chem Phys, State Key Lab Mol React Dynam, 457 Zhongshan Rd, Dalian 116023, Liaoning, Peoples R China
3.Sci & Technol Surface Phys & Chem Lab, POB 9-35, Jiangyou 621908, Sichuan, Peoples R China
4.Xidian Univ, Sch Phys & Optoelect Engn, Xian 710071, Shaanxi, Peoples R China
5.China Acad Engn Phys, Inst Mat, 596 Yinhe Rd 7th Sect, Chengdu 610200, Sichuan, Peoples R China
6.Southern Univ Sci & Technol, Dept Chem, 1088 Xueyuan Rd, Shenzhen 518055, Guangdong, Peoples R China
7.Univ Chinese Acad Sci, 19A Yuquan Rd, Beijing 100049, Peoples R China

Wang, Tianjun,Hao, Qunqing,Wang, Zhiqiang,et al. Deuterium Kinetic Isotope Effect in the Photocatalyzed Dissociation of Methanol on TiO2(110)[J]. Journal of Physical Chemistry C,2018,122(46):26512-26518.

Wang, Tianjun.,Hao, Qunqing.,Wang, Zhiqiang.,Mao, Xinchun.,Ma, Zhibo.,...&Yang, Xueming.(2018).Deuterium Kinetic Isotope Effect in the Photocatalyzed Dissociation of Methanol on TiO2(110).Journal of Physical Chemistry C,122(46),26512-26518.

Wang, Tianjun,et al."Deuterium Kinetic Isotope Effect in the Photocatalyzed Dissociation of Methanol on TiO2(110)".Journal of Physical Chemistry C 122.46(2018):26512-26518.