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 H2 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 H2 molecule. To correlate the DFT results with catalytic experiments, 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.