Stable Cuδ+ species - Catalyzed CO₂ hydrogenation to methanol in silanol nests on Cu/S-1 catalyst

Fine-regulating the electronic state of metal species to enhance the catalytic activity has demonstrated to be an effective yet persistent challenge. The study introduces an innovative method for enhancing catalytic performance in hydrogenating CO2 to methanol via modulating copper-support interactions through the adjustment of surface silanol groups. The developed Cu/S-1 catalyst exhibits outstanding results: 85% methanol selectivity and 8.0% CO2 conversion under 240 °C and 3 MPa, while maintaining stability for over 200 h. This performance surpasses that of the Cu/SiO2 catalyst. Analyses indicate that the higher presence of Cuδ+ species in Cu/S-1 is attributed to the silanol nests in S-1 zeolite, which can stabilize these species and prevent the further reduction. The study identifies Cuδ+ and Cu0 as active species for CH3OH and CO production, respectively. A higher Cuδ+/Cu0 ratio eventuates better CO2 conversion and CH3OH selectivity. Copper-support interaction is a key to the exceptional stability of the catalyst.