Resumo

RANGEL, R. et al. Study of the effect of different mixed supports on the catalytic activity and the structure of Bi₂Mo_(x)W_(1-x) O₆ catalyst. Rev. Int. Contam. Ambient [online]. 2014, vol.30, n.4, pp.417-427. ISSN 0188-4999.

A series of Bi₂Mo_xW_1-xO₆ catalysts supported on Al₂O₃-SiO₂, SiO₂-TiO₂ and activated carbon (C*) were synthesized. The aim was to compare the different supports and calcination temperature of catalysts, studying their efficiency and activation temperature in the CO oxidation reaction. The catalysts active phase, Bi₂Mo_xW_1-xO₆, was made by means of chemical precipitation procedure starting from high purity (NH₄)6Mo₇O₂₄•4H₂O, (NH₄)₆W₁₂O₆•H₂O, Bi(NO₃)₂•5H₂O compounds, whichafterwards, were supported on Al₂0₃-Si02, Si0₂-Ti0₂ and C* through impregnation. The catalysts characterization was carried out by means of X ray diffraction analysis (XRD), scanning electron microscopy (SEM) and surface area determination (BET method). Regarding the catalytic activity the Bi₂Mo_xWi_-x0₆ /C* compound synthesized at 500 °C was the best catalyst being activated at 125 °C reaching 90 % conversion. It is concluded that was observed an effect of calcination temperature and the support on the different values reached for the catalytic activity.

Palavras-chave : catalytic activity; carbon monoxide oxidation; mixed oxides; supported catalyst.