In Situ Dynamic Structural Changes of Ruthenium-Loaded MoO₃ for Photothermal Catalytic CO₂ Reduction

Hydrogen spillover has been widely recognized as a pivotal phenomenon in heterogeneous catalysis, yet the global impact of active hydrogen species on support materials remains underexplored, hindering the establishment of robust structure–performance correlations. In this study, we employed in situ scanning transmission electron microscopy (in situ STEM) to investigate the support effect in ruthenium-loaded molybdenum trioxide (Ru/MoO3) catalysts during the reversed water–gas shift reaction (RWGS). Our observations revealed that the presence of active hydrogen atoms markedly enhanced the evolution of lattice oxygen from MoO3, resulting in the transformation of the Ru-MoO3 nanosheet into a porous structure reminiscent of a jigsaw puzzle, thereby creating active CO2 sites on the catalytic surface. The controlled surface reconstruction of Ru-MoO3 enabled 14.3% CO2 conversion and nearly 100% CO selectivity at 300 °C, closely approaching the thermodynamic equilibrium limit of the RWGS reaction. These findings provide critical insights into the influence of active hydrogen on the morphology and crystal structure of supports at a comprehensive scale, underscoring its potential to enhance photothermal catalytic CO2 hydrogenation performance and paving the way for the development of more efficient CO2 conversion technologies.