Operando tracking of photothermal effects on CO2-to-methanol pathways over industrial Cu–Zn catalysts

Abstract

The introduction of external field assistance in CO₂ hydrogenation systems presents an effective approach to achieving superior methanol synthesis performance. However, there is a lack of adequate research on how light modulates or alters the reaction process at different temperatures and pressures. Here, we demonstrate that light irradiation enables remarkable activity enhancements, especially at lower pressures, in conventional Cu/ZnO/Al₂O₃ (CZA) catalytic systems through strategically designed operando characterization studies. Systematic investigation of pressure-light-temperature coupling effects reveals that photon energy input significantly elevates methanol productivity, with particularly pronounced enhancements (17–100% activity increase vs. thermal catalysis) observed under reduced pressure conditions. Notably, comparable activity levels emerge between 2 MPa and 3 MPa systems under photothermal operation at equivalent temperatures. Mechanistic analysis uncovers that localized surface plasmon resonance (LSPR) excitation in Cu nanostructures drives dual activation pathways: (1) low-barrier CO₂ activation through charge transfer mechanisms and (2) enhanced H₂ dissociation kinetics. Critical to the performance enhancement are the light-induced dynamic shifts in Cu oxidation states and the synergistic coordination between Cu⁰–CO and dissociated hydrogen species. These findings establish photonic field modulation as a powerful strategy for developing energy-efficient catalytic systems that operate under mild conditions.