High surface-area semiconductor nanorods decorated with RuO2 as a surface functional component are investigated. Main attention is focused on the most important and least explored study of photoexcited hole relaxation process. DFT-based simulation approach for the charge transfer dynamics at the interface of the RuO2 nanocatalyst and TiO2 nanorod is applied. TiO2 nanorod is modeled as a periodic anatase (100) slab functionalized with RuO2 nanocatalyst. In this model, a photoexcitation promotes a non-equilibrium state of a material, so that the electronic states are recalculated for each atomic configuration along molecular dynamics trajectory produced during the simulation to compute the coupling between the electronic and nuclear degrees of freedom. Photon-to-exciton conversion efficiencies and photo-excited charge carriers lifetime are estimated. According to computed dynamics, hole excitation relaxes to valence band maximum faster than electronic one towards to conduction band minimum. This leads to creation of positively charged areas on the nanorod's surface that is an important prerequisite for oxidatation catalysis. Our computation identifies optimal composition and morphology of nanocatalyst for such applications as water splitting for hydrogen production or solar cells.D.K. acknowledges the support by South Dakota Governor's Office of Economic Development and NSF award EPS0903804.  Computational effort was supported by DOE, BES-Chemical Sciences, and NERSC Contract No. DE-AC02-05CH11231, allocation Award 84577 �Computational Modeling of Photo-catalysis and Photoinduced Charge Transfer Dynamics on Surfaces�.

Dissipative carrier dynamics for photocatalysis

243rd National Meeting (2012)

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