Photocatalytic CO2 Reduction Enhanced by Synergetic Interactions among Photon Phonon and Molecule

Abstract: Photocatalytic CO2 reduction is limited by inefficient CO2 activation and poor solar spectrum utilization. Here, we discovered and revealed the vibration coupling mechanism among photons, phonons, and molecules, which remarkably enhances photocatalytic catalysis of CO2 into fuels. We designed the nitrogen-doped Cu2O-based catalyst loaded onto the quartz optical substrate. The N-doping Cu2O converts linearly geometry of adsorbed CO2 molecules, which efficiently lowers the activation barrier and facilitates CO2 dissociation. Once the Cu-based catalyst is combined with a micro-pillar quartz film, the system induces vibrational strong coupling (VSC) between the asymmetric CO2 stretching mode and surface phonon polariton resonances. These resonances arise from the photothermal conversion of incident solar photons on the micro-pillars. The resonant coupling phenomena were further verified by Fourier-transform infrared spectroscopy using Synchrotron Radiation Source (SRS), which directly confirmed the interactions between molecular vibrations and photonic-phononic modes. The synergetic functions originated from this hybrid architecture achieve a CO yield of 167.7 umol h-1 g-1 under pure water conditions, which is the highest reported yield for Cu2O-based photocatalysts with 46% enhancement over non-VSC systems. This work uncovers a novel photo-thermal mechanism. It further provides a new strategy to control bond activation in photocatalytic CO2 conversion through light-vibration-matter coupling.