Studies On Synthesis And Structure Properties Of Co-M-Al Mixed Oxides Films And Its Catalytic Performance

The design and synthesis of the novel film catalyst in recent years have become one of research hotspots in the field of heterogeneous catalyst. Benzyl alcohol and ethyl benzene is an important chemical raw material because their oxidation products of benzaldehyde and acetophenone have extensive application value. Ternary LDHs films immobilised on AAO/A1 substrate were fabricated by in-situ method used ammonia as precipitant and their derivative films (MMO) were obtained by calcination method, and applied to the oxidations of benzyl alcohol and ethyl benzene. We also investigated the effect of component and microstructure on catalytic activity of the as-prepared film catalysts. Detailed results are as following:1. First, we prepared CoNiAl-LDH films on AAO/Al substrate by in-situ growth method, and then after calcining, CoNiAl-MMO films were obtained. The as-fabricated films were charactered by structural, compositional and morphological analyses, which exhibited porous surface structure and homogeneous composition. The CoNiAl-MMO films may be composed of a solid solution of Co3O4, CoAl2O4, NiAl2O4 and NiCo2O4 spinels. The resulting film catalysts were used to oxidation of benzyl alcohol, showing that CoNiAl-MMO film exhibited the highest conversion of 29.3% among them, which is 2.44 times that of CoNiAl-MMO powder catalyst, and 1.66 times that of CoAl-MMO binary film catalyst, while the conversion of CoNiAl-LDH film catalyst reach 14.6%. which is 3.11 times that of CoNiAl-LDH powder catalyst. In addition, we also studied the influence of the composition and surface structure of the films on their catalytic performance by some modern analysis method, showing that MMO films have higher catalytic activity because of the existence of strong interaction between Co and Ni, fully exposed active sites and porous surface structure.2. Novel CoMnAl mixed metal oxide (CoMnAl-MMO) film with surface intercrossed nanoplatelets was fabricated successfully on the anodic aluminum oxide/aluminum substrate via a single-source precursor route, in which CoMnAl-LDH was in situ grown on AAO/Al substrate by ammonia method and followed by calcination. The results revealed that the resulting CoMnAl-MMO film possessed unique surface porous microstructure. Furthermore, as-fabricated CoMnAl-MMO film exhibited greatly enhanced catalytic performance in the oxidation of ethylbenzene, compared with pristine CoMnAl-MMO powder.