Ag24Au cluster decorated mesoporous Co3O4 for highly selective and efficient photothermal CO2 hydrogenation

Photothermal carbon dioxide hydrogenation represents a promising route to reduce the emission of greenhouse gas CO 2 and produce value-added chemicals, but the selectivity and stability of photothermal catalysts need to be improved. Herein, we report the rational fabrication of well-defined Ag 24 Au cluster decorated highly ordered nanorod-like mesoporous Co 3 O 4 (Ag 24 Au/meso-Co 3 O 4 ) for highly efficient and selective CO 2 hydrogenation. The orderly assembled meso-Co 3 O 4 nanorods were prepared via a nanocasting method, offering large surface area and abundant active sites for CO 2 adsorption and conversion. Moreover, the catalytic activity and selectivity were further improved by molecule-like Ag 24 Au cluster decoration and reaction temperature optimization. The Ag 24 Au/meso-Co 3 O 4 composite catalyst exhibited an ultrahigh CH 4 yield rate of 204 mmol·g −1 ·h −1 and a greatly improved CH 4 selectivity of 82% for CO 2 hydrogenation, significantly higher than those of pristine meso-Co 3 O 4 catalyst. The mechanism of the photothermal catalytic performance improvement was verified by CO 2 temperature-programmed desorption and time-resolved transient photoluminescence, revealing that CO 2 molecules underwent a vigorous adsorption and rapid activation process over Ag 24 Au/meso-Co 3 O 4 . The hot electrons created by the localized surface plasmon resonance effect of Ag 24 Au clusters facilitated the charge transfer for subsequent multi-electron CO 2 hydrogeneration processes, resulting in a significant increase in the productivity and selectivity for CO 2 -to-CH 4 conversion. This work suggests that the rational coupling of well-defined metal atom clusters and ordered transition metal compound nanostructures could open a new avenue towards photo-induced green chemistry processes for efficient CO 2 recycling and reutilization.