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

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