Atomically Precise Pd Species Accelerating CO 2 Hydrodeoxygenation into CH 4 with 100% Selectivity

High Resolution Image Download MS PowerPoint Slide High-rate CO 2 -to-CH 4 photoreduction with high selectivity is highly attractive, which is a win-win strategy for mitigating the greenhouse effect and the energy crisis. However, the poor photocatalytic activity and low product selectivity hinder the practical application. To precisely tailor the product selectivity and realize high-rate CO 2 photoreduction, we design atomically precise Pd species supported on In 2 O 3 nanosheets. Taking the synthetic 1.30Pd/In 2 O 3 nanosheets as an example, the aberration-correction high-angle annular dark-field scanning transmission electron microscopy image displayed the Pd species atomically dispersed on the In 2 O 3 nanosheets. Raman spectra and X-ray photoelectron spectra established that the strong interaction between the Pd species and the In 2 O 3 substrate drove electron transfer from In to Pd species, resulting in electron-enriched Pd sites for CO 2 activation. Synchrotron-radiation photoemission spectroscopy demonstrated that the Pd species can tailor the conduction band edge of In 2 O 3 nanosheets to match the CO 2 -to-CH 4 pathway, instead of the CO 2 -to-CO pathway, which theoretically accounts for the high CH 4 selectivity. Moreover, in situ X-ray photoelectron spectroscopy unveiled that the catalytically active sites had a change from In species to Pd species over the 1.30Pd/In 2 O 3 nanosheets. In situ FTIR and EPR spectra reveal the atomically precise Pd species with rich electrons prefer to adsorb the electrophilic protons for accelerating the *COOH intermediates hydrogenation into CH 4 . Consequently, the 1.30Pd/In 2 O 3 nanosheets reached CO 2 -to-CH 4 photoconversion with 100% selectivity and 81.2 μmol g –1 h –1 productivity.