Cu₂O(100) surface as an active site for catalytic furfural hydrogenation

In order to investigate the major active site of Cu-based catalysts in furfural (FAL) hydrogenation, theoretical calculations were combined with empirical analyses. The adsorption of FAL and H-2 on the Cu(111), CuO(100), and Cu2O(100) surfaces was compared based on density functional theory (DFT) calculations. The migration barrier of the dissociatively adsorbed H atoms on different surfaces was also calculated. It is demonstrated that the Cu2O(100) surface has the largest FAL adsorption energy of 1.63 eV and an appropriate Cu-Cu distance for adsorption and preferential dissociation of the H-2 molecule. To correlate the DFT results with catalytic ex-periments, mesoporous copper oxides (m-CuO) were prepared under controlled reduction conditions. The overall activity of the m-CuO catalysts is determined by the concentration of exposed Cu+. The combined results from DFT calculations and experiments show that Cu2O is a major active species promoting the high activity of FAL hydrogenation.