CeO2 supported Pd dimers boosting CO2 hydrogenation to ethanol

Hydrogenation of CO2 into valuable chemicals is of great significance but very challenging due to its chemical inertness and selectivity controlling. Here, we report that CeO2 supported Pd dimers can efficiently convert CO2 to ethanol with significantly higher activity and selectivity compared to those in literatures, which gives a selectivity of 99.2 % to ethanol with a space-time yield of 45.6 g(ethanol) g(Pd)(-1) h(-1). The Pd dimers possessing unique Pd2O4 configuration and high homogeneity enables to directly dissociate CO2 to CO, trigger C-C coupling but appropriately inhibit further C2+ coupling, which benefits to selectively form ethanol. The Pd2O4 configuration can strongly bind CO on Pd-2/CeO2, which prevents CO desorption and promotes the coupling between CO and CH3 intermediates to form the precursor of ethanol. The strategy of constructing atom-precision active sites reported in this work opens new avenues to develop highly selective catalysts for CO2/CO hydrogenation reactions.