Abstract: Zirconia(ZrO₂) was supported on active carbon(AC) or siliceous MCM-41 mesoporous materials(ZrO₂/MCM-41) respectively through the impregnation method, At the same time, these samples were cha-racterized by XRD, N₂ adsorption-desorption, XPS, TG-DSC and FTIR spectra of adsorbed pyridine methods. Their catalytic activities in the Meerwein-Ponndorf-Verley(MPV) reduction of acetophenone with α-propanol as a hydrogen donor were investigated, and compared to that of hydrous zirconia to study the support effect on their catalytic activities. The results showed that catalytic activity was significantly improved upon loading zirconia on MCM-41 support, due to the formation of Si-O-Zr bond between zirconia and MCM-41 supported, which resulted in the formation of highly dispersed amorphous zirconia in the catalyst, consequently a marked increase of the amount of the Zr-OH group, the strengthening of Lewis acidity and an appearance of Brnsted acid sites. In contrast to ZrO₂/MCM-41, no obvious increase of catalytic activity was observed after loading zirconia on AC support owing to the weak interaction between zirconia and AC support, which resulted in the lower dispersion of zirconia on AC support, consequently a less increase of number of Zr-OH groups and weak Lewis acidity. However, ZrO₂/AC calcined at higher temperature(400-600 ℃) still retained steady activity, which may be due to the dredging of pores in AC during the calcination, and the increase of concentration of acetophenone near the active sites via the π-π electron interaction between the benzene ring in the acetophenone and graphite layer of AC support.

Key words: Zirconia, MCM-41 mesoporous molecular sieve, Active carbon(AC), Acetophenone, Hydrogen transfer reaction