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Title: Mechanism of photocatalytic water oxidation on small TiO 2 nanoparticles

Here, we present the first unconstrained nonadiabatic molecular dynamics (NAMD) simulations of photocatalytic water oxidation by small hydrated TiO 2 nanoparticles using Tully surface hopping and time-dependent density functional theory. The results indicate that ultrafast electron–proton transfer from physisorbed water to the photohole initiates the photo-oxidation on the S 1 potential energy surface. The new mechanism readily explains the observation of mobile hydroxyl radicals in recent experiments. Two key driving forces for the photo-oxidation reaction are identified: localization of the electron–hole pair and stabilization of the photohole by hydrogen bonding interaction. Our findings illustrate the scope of recent advances in NAMD methods and emphasize the importance of explicit simulation of electronic excitations.
Authors:
ORCiD logo [1] ; ORCiD logo [1] ; ORCiD logo [2] ;  [1] ; ORCiD logo [3] ; ORCiD logo [1]
  1. Univ. of California, Irvine, CA (United States). Dept. of Chemistry
  2. Imperial College, London (United Kingdom). Dept. of Chemistry; Univ. College London, London (United Kingdom). Dept. of Chemistry
  3. Univ. College London, London (United Kingdom). Dept. of Chemistry
Publication Date:
Grant/Contract Number:
SC0008694
Type:
Accepted Manuscript
Journal Name:
Chemical Science
Additional Journal Information:
Journal Volume: 8; Journal Issue: 3; Journal ID: ISSN 2041-6520
Publisher:
Royal Society of Chemistry
Research Org:
Univ. of California, Irvine, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1423815