Boosting Hydrogenation of CO2 Using Cationic Cu Atomically Dispersed on 2D γ-Al2O3 Nanosheets.

The continuous development of novel catalytic approaches is crucial for advancing efficient CO2 hydrogenation processes. Drawing inspiration from single-atom catalysis and 2D materials, we designed a new 2D single-atom catalyst with excellent thermal stability by thermally treating Cu-adsorbed γ-AlOOH nanosheets, which yielded a Cu/γ-Al2O3 catalyst with high activity in the hydrogenation of CO2-yielding methanol (CH3OH), dimethyl ether (DME), and CO as products. The active Cu sites are monodispersed and highly stable due to their cationic oxidation state and their substitution for pentacoordinated aluminum (AlP) sites on particle surfaces. This study demonstrates an efficient approach for achieving a high CO2 hydrogenation rate (30.45 mol mol-1 h-1) using a catalyst system that lacks metallic Cu centers, traditionally considered essential for H₂ dissociation, and employs what was previously thought to be an inert metal oxide (γ-Al2O3) for CO and CH3OH production. Ongoing mechanistic studies aim to elucidate the synergy between cationic Cu single atoms and γ-Al2O3, a Lewis acid support, in facilitating hydrogen (H2) activation and methanol formation.