Four-electron transfer reactions in water photo-oxidation on TiO2 have been studied using a newly developed method.  This method combines ab intio molecular dynamics simulations and free energy perturbation theory to compute thermochemistry of proton coupled electron transfer (PCET).[1] Decomposition of dehydrogenation into deprotonation and oxidation allows us to scrutinize the PCET steps at the interface and better understand the activity/inactivity of catalysts.  On the other hand, such a separation is crucial to understand the error in the calculations using standard GGA density functionals.[2] The inaccuracy in GGAs, named delocalization error, has profound consequence in calculation of defects in semiconductors, and has been widely studied and relatively well understood in solid state community.[3] In this respect, there is a close parallel between semiconductor photoelectrocatalysis and defect physics.[4] Inclusion of a fraction of exact exchange in density functionals can alleviate this error, giving rise to correct localization of electronic holes on reaction intermediates at the interface. On the basis of understanding of delocalization error, we will present the energetics of reaction intermediates calculated by using a screened hybrid functional (HSE06[5]), and also some discussions on reaction mechanism and activity of materials.ReferencesJ. Cheng, M. Sprik, Phys. Chem. Chem. Phys. 2012, 14, 11245.J. Cheng, M. Sulpizi, J. VandeVondele, M. Sprik, ChemCatChem, 2012, 4, 636.C. G. Van de Walle, A. Janotti, Phys. Status Solidi B 2011, 248, 19.C. Adriaanse, J. Cheng, M. Sulpizi, J. VandeVondele, M. Sprik, submittedA. V. Krukau, O. A. Vydrov, A. F. Izmaylov, G. E. Scuseria, J. Chem. Phys. 2006, 125, 224106.

Proton coupled electron transfer in water photo-oxidation at rutile TiO<sub>2</sub>(110) water interface

245th National Meeting (2013)

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Proton coupled electron transfer in water photo-oxidation at rutile TiO2(110) water interface

Proton coupled electron transfer in water photo-oxidation at rutile TiO₂(110) water interface