Stretching vibration driven adiabatic transfer kinetics for photoexcited hole transfer from semiconductor to adsorbate.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39384738.
- Also identified by DOI 10.1038/s41467-024-52991-2 and PMC identifier 11479618.
- Licence recorded as CC BY-NC-ND.
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Abstract
Interfacial hole transfer from a photoexcited semiconductor to surface adsorbates is pivotal for initiating solar-to-chemical energy conversion, yet the atomic-level transfer kinetics remains elusive. Using the methoxy/TiO<sub>2</sub>(110) system as an archetype, here we elucidate the hole transfer mechanism from hole-trapping lattice oxygen to the methoxy adsorbate at gas/solid and liquid/solid interfaces through molecular dynamics simulations and static minimum energy path calculations. Instead of direct nonadiabatic hopping, we uncover an adiabatic migration pathway adapted to local substrate relaxation, driven by a bond-stretching mechanism supported by stronger Ti-O stretching vibrations. Notably, this mechanism persists at the aqueous methoxy/TiO<sub>2</sub>(110) interface, albeit hindered by interfacial water and coadsorbates. Surprisingly, the hole transfer barriers across various photoexcited adsorbate/TiO<sub>2</sub> interfaces correlate more closely with the vertical excitation energies of the adsorbates rather than their redox potentials, indicating an early-type transition-state nature. These insights deepen our understanding of elementary hole transfer kinetics in surface photochemistry.