Facile benzene reduction promoted by a synergistically coupled Cu–Co–Ce ternary mixed oxide

Hydrogenation of aromatic rings promoted by earth-abundant metal composites under mild conditions is an attractive and challenging subject in the long term. In this work, a simple active site creation and stabilization strategy was employed to obtain a Cu(+)-containing ternary mixed oxide catalyst. Simply by pre-treatment of the ternary metal oxide precursor under a H(2) atmosphere, a Cu(+)-derived heterogeneous catalyst was obtained and denoted as Cu(1)Co(5)Ce(5)O(x). The catalyst showed (1) high Cu(+) species content, (2) a uniform distribution of Cu(+) doped into the lattices of CoO(x) and CeO(2), (3) formation of CoO(x)/CuO(x) and CeO(2)/CuO(x) interfaces, and (4) a mesoporous structure. These unique properties of Cu(1)Co(5)Ce(5)O(x) endow it with pretty high hydrogenation activity for aromatic rings under mild conditions (100 °C with 5 bar H(2)), which is much higher than that of the corresponding binary counterparts and even exceeds the performance of commercial noble metal catalysts (e.g. Pd/C). The synergetic effect plays a crucial role in the catalytic procedure with CeO(2) functioning as a hydrogen dissociation and transfer medium, Cu(+) hydrogenating the benzene ring and CoO(x) stabilizing the unstable Cu(+) species. This will unlock a new opportunity to design highly efficient earth-abundant metal-derived heterogeneous catalysts via interface interactions.