CO₂ hydrogenation to acetic acid and methyl acetate via tandem catalysis

Selective hydrogenation of CO₂ into high-value C₂₊ oxygenates, such as acetic acid (AA), methyl acetate (MA), and ethanol, is highly attractive yet remains a significant challenge. This study demonstrates an innovative tandem catalysis system for converting CO₂ to AA and MA, employing GaZrO_x and hydrophobically modified MOR-8-C1@PC (PTFE+CNTs) catalysts. The upstream GaZrO_x drives CO₂ hydrogenation to produce an effluent gas with a controlled CO/(DME + CH₃OH) ratio of approximately 4, facilitating the subsequent carbonylation reaction over the MOR-based catalyst. For the downstream catalyst, surface silanization of MOR zeolite combined with a hydrophobic promoter effectively prevents water (generated during CO₂ hydrogenation) from entering the zeolite channels and greatly enhances the carbonylation activity and catalyst stability. Results show that at a CO₂ conversion of 27%, the selectivity towards AA and MA in the organics reaches up to 78%, with no catalyst deactivation observed over 50 hours. This strategy offers an efficient approach for converting CO₂ into C₂₊ oxygenates, with promising implications for sustainable chemical production.