Unraveling interfacial electron transfer dynamics in noble metal cocatalyst modified ferroelectric photocatalysts via nonadiabatic molecular dynamics simulations

Abstract

Rapid interfacial electron transfer (IET) from a light-absorbing semiconductor to a metal cocatalyst in typical photocatalysts is essential to enable high-efficiency solar energy conversion. However, the underlying dynamics of this process have long remained poorly understood, posing challenges for the rational construction of high-performance photocatalysts. In this work, taking ferroelectric Bi₃TiNbO₉ (BTNO) and noble metals (NMs, Rh, Pd, and Pt) as a light absorber and cocatalyst, respectively, three photocatalysts (BTNO/Rh, BTNO/Pd, and BTNO/Pt) were constructed, and their IET behaviors were systematically investigated by nonadiabatic molecular dynamics (NAMD) simulations. Consequently, BTNO/Rh demonstrates the highest IET efficiency with an IET time (τ) of 0.304 ps among the three photocatalysts, followed by BTNO/Pt (τ = 0.594 ps) and then BTNO/Pd (τ = 1.895 ps). By extending the study to additional NM cases (Ir, PdPt, Pt₃Ru, and Ru₃Ir), an exponential decay relationship with a strong correlation (R² = 0.99) was established between the IET time and the average density of states within the energy range from the conduction band minimum of BTNO to the Fermi level of the photocatalytic system. This correlation can be generalized to other photocatalysts, such as Bi₄Ti₃O₁₂/NM (R² = 0.98) and SrTiO₃/NM (R² = 0.94). Therefore, the average density of states represents a robust descriptor for the prediction of IET efficiency in the photocatalysts, which can be qualitatively estimated by quickly examining the electronic structures of candidate cocatalysts. Overall, the insights into the IET dynamics gained here provide crucial guidance for developing excellent photocatalysts.