CO 2 Hydrogenation on Cu/Al 2 O 3 : Role of the Metal/Support Interface in Driving Activity and Selectivity of a Bifunctional Catalyst

Selective hydrogenation of CO 2 into methanol is a key sustainable technology, where Cu/Al 2 O 3 prepared by surface organometallic chemistry displays high activity towards CO 2 hydrogenation compared to Cu/SiO 2 , yielding CH 3 OH, dimethyl ether (DME), and CO. CH 3 OH formation rate increases due to the metal–oxide interface and involves formate intermediates according to advanced spectroscopy and DFT calculations. Al 2 O 3 promotes the subsequent conversion of CH 3 OH to DME, showing bifunctional catalysis, but also increases the rate of CO formation. The latter takes place 1) directly by activation of CO 2 at the metal–oxide interface, and 2) indirectly by the conversion of formate surface species and CH 3 OH to methyl formate, which is further decomposed into CH 3 OH and CO. This study shows how Al 2 O 3 , a Lewis acidic and non‐reducible support, can promote CO 2 hydrogenation by enabling multiple competitive reaction pathways on the oxide and metal–oxide interface.