Polaron-assisted nonadiabatic dynamics in protonated TiO2 with surface water molecule
Zhongfei Xu,
Chuanjia Tong,
Rutong Si,
Gilberto Teobaldi,
Limin Liu
Affiliations
Zhongfei Xu
The Key Laboratory of Resources and Environmental System Optimization, Ministry of Education, College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, China
Chuanjia Tong
School of Physics and Electronics, Central South University, Changsha 410083, China
Rutong Si
Beijing Computational Science Research Center, Beijing 100193, China; The Abdus Salam International Centre for Theoretical Physics, Trieste 34151, Italy
Gilberto Teobaldi
Scientific Computing Department, Science and Technology Facilities Council UK Research and Innovation (STFC-UKRI), Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom; School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, United Kingdom
Limin Liu
School of Physics, Beihang University, Beijing 100191, China; Corresponding author.
We investigated the polaron-assisted nonadiabatic dynamics in protonated TiO2, as well as the polaron-H2O coupling and its effects on the relaxation of photogenerated electrons. We observed that different polaron hopping regimes result in varied nonadiabatic couplings and relaxations of excited electrons from the conduction band minimum to the gap states of protonated TiO2, with a weak dependence on the actual trapping site of the polaron. Surface-adsorbed H2O molecules can attract polarons toward the adsorbed Ti sites, with the coupling between H2O and the polaron being inversely proportional to their distance. Our findings suggest that the lifetime of the photogenerated charge carriers can be extended by reducing the polaron-H2O distances, with expected benefits to the efficiency of the reduced TiO2 samples for photocatalytic applications.
