Correlating Ligand Properties with Photocatalytic Efficiency: A Computational Framework for Interface Engineering

We present the application of the Marcus–Hush formalism as a theoretical framework to investigate charge transfer dynamics in ligand-protected Au systems. By integrating key parameters such as energy level differences and electronic coupling, this approach enables the prediction of photocatalytic efficiency in electron-driven water splitting. Simulations of diverse ligand-functionalized AuNPs establish a clear correlation between charge transfer rates and hydrogen evolution, specifically for functionalized AuNPs bearing aromatic thiols with various para-substituents. Additionally, we extend this framework to selenol-substituted systems, revealing that while selenols perform comparably to thiols in some cases, they do not consistently enhance photocatalytic activity. Beyond electron-driven hydrogen production, we further explore the role of ligand chemistry in modulating hole transfer processes relevant to oxidative half-reactions. In this context, the OH-thiol ligand-functionalized AuNP emerges as the most effective photocatalyst for hole-driven reactions. Overall, this study provides a systematic methodology for screening and designing ligand-functionalized AuNP photocatalysts, offering mechanistic insights into how ligand properties govern photocatalytic performance.