Bridging Ideal Model Surfaces and Practical Material Surfaces : Unveiling Reaction Field of Photocatalytic Water-Splitting Hydrogen Evolution via <i>Operando</i> Infrared Spectroscopy

Achieving carbon neutrality by 2050 and transitioning to a sustainable society requires innovations in alternative energy technologies. Photocatalytic hydrogen production from H2O using solar energy offers a promising solution but faces significant challenges in bridging the “pressure gap” (reactions on earth occur in gas or solution phases rather than vacuum), “energy gap” (reactions on earth occur at ambient to high temperatures instead of cryogenic conditions), and “material gap” (most catalysts have ill-defined, heterogeneous surfaces rather than idealized single-crystal substrate surfaces). Addressing these gaps necessitates advanced operando experimental approach under realistic conditions. This study highlights our recent advancements in developing operando measurement and analysis techniques that can establish correlations between macroscopic functionalities with microscopic structural and dynamic properties. These approaches provide new insights into the reaction fields of photocatalytic water-splitting systems, focusing on interfacial molecular science and metal-semiconductor complex interface science.