Applied Catalysis B: Environmental, Vol.127, 246-254, 2012
Catalytic combustion of chlorobenzene on the Ln modified Co/HMS
Lanthanide (Ln, including La, Ce and Nd) modified Co/HMS was prepared via two pathways: extra-framework modified post-loading and framework modified direct synthesis. The influence of modified methods, rare earths kind and rare earths loading on the catalytic performance of Co/HMS was studied by the catalytic combustion of chlorobenzene (CB). It was found that the extra-framework Ce modified catalysts show the better catalytic performance than the framework Ln modified ones due to that the forming of CeO2 is advantaged to obtain the fine Co3O4 crystal clusters and the reduction of Ce4+ ions to Ce3+ species probably will promote neighboring reduction of Co species. The suitable extra-framework Ce loading (6%, mass fraction) can effectively ameliorate the redox ability of Co species in the channel of HMS. Since the channel of HMS itself and Co(NO3)(3)center dot 6H(2)O aqueous solution both are hydrophilic, the polarity adjusting function of framework Ln to the internal reaction between Co species and support is not great in this case. However, the slightly improved redox ability and weak acidity originated from framework Ln still can do some contribution to the catalytic performance. The electronic structure of Co and Ce is advantageous to the delocalization of pi-electrons and the forming of radical species. (C) 2012 Elsevier B.V. All rights reserved.