Manganese containing copper aluminate catalysts: Genesis of structures and active sites for hydrogenation of aldehydes

Copper aluminate spinel (CuO.CuAl2O4) is the favoured Cr-free substitute for copper chromite catalyst (CuO.CuCr2O4) in industrial hydrogenation of aldehydes. New insights catalytic mechanism were obtained by systematically studying structure and activity these catalysts including effects manganese as a component. The butyraldehyde to butanol was studied model reaction active characterised using X-ray diffraction, temperature programmed reduction, N2O chemisorption, EXAFS XANES, in-situ investigations. reduced lattice that stabilised protons, with metal nanoparticles grown upon its surface. Incorporation Mn into has profound effect on structure. stabilises towards reduction CuII Cu0 occupation tetrahedral sites cations, but also causes decreased activity. Structural data, combined catalysis, indicate predominantly interface-based mechanism, involving both nanoparticle surface protonation aldehyde. electron reservoir metallic particles regenerated dissociative adsorption oxidation H2 generated protons are stored phase, acting proton reservoir. Cu(I) species located within identified XANES probably not involved cycle.