Metal-organic chemical vapor deposition of Cu(acac)(2) for the synthesis of Cu/ZSM-5 catalysts for the oxidation of toluene

摘要

A heterogeneous catalyst (Cu/ZSM-5) was prepared by a metal-organic chemical vapor deposition (MOCVD) method under nitrogen atmosphere using Cu(acac)(2) as the copper precursor, and further characterized by XRD, AAS, SEM, BET, H-2-TPR and XPS as well as catalytic activity performance for the oxidation of toluene. N-2 adsorption data revealed that the samples (CVD-4) prepared by MOCVD with calcination at 500 degrees C for 4 h possessed higher surface areas than that (CVD-BC) not calcined. The results of XPS demonstrated that CVD-4 exhibited higher redox property and more surface oxygen species compared with CVD-BC and IM (Cu/ZSM-5 catalyst prepared by impregnation). In particular, the CVD-4 catalysts prepared by MOCVD with calcinations showed the highest catalytic activity for toluene oxidation with 90% conversion of toluene at 293 degrees C with the feed concentration of 1000 ppm and GHSV of 15,000 h(-1), which was lower than IM (310 degrees C). The results of a reaction durability test revealed that the Cu/ZSM-5 catalysts prepared by MOCVD possessed excellent durability for toluene oxidation for 63 h, while the conversion of toluene fell down from 90% to 60% after 48 h over IM catalyst.