Insights into reduction of CO2 to CO catalyzed by pyramidal-4Ni clusters supported on doped CeO2(111)

Converting CO2 into valuable chemicals has become a widely used research method for CO2 conversion. In this work, the catalytic performance of pyramidal-4Ni catalysts supported on rare earth metal-doped CeO2 toward CO2 reduction reaction (CO2RR) was investigated by using density-functional theory calculations. For rare earth metal-doped CeO2, 2Ce is substituted by 2 trivalent cations and at the same time one oxygen vacancy is created to make charge compensation. We investigated the oxygen vacancy nearest (V-O,V-N) and next-nearest (V-O,V-NN) to 4Ni, and found releasing CO and CO2 dissociation are the rate-determining steps, respectively, via the path of V-O,V-N and V-O,V-NN. Among the studied dopants (Ga, Sb, Lu, Gd, Pr, La, Bi), Gd is identified as the best dopant for catalyzing the reduction of CO2 at 823 K, with the turn-over frequency (TOF) of 10(4) times as large as that over 4Ni supported on pure CeO2. This exploration provides theoretical support and guidance for the research and application of rare earth metal-doped CeO2-loaded Ni catalysts in the field of CO2 reduction.