Comparative Study Of The Various Modification Effect On Copper Catalyst For Complete CO Oxidation

CO complete oxidation reaction can be applied to many aspects, such as vehicle exhaust cleaning, elimination of CO in spacecraft and submarine, CO sensors, gas purification of closed CO2laser, mine rescue devices and purification of the feed stream of fuel cells, and also due to the CO oxidation reaction is simple and easy to operate, it is often used as a probe reaction to study the reaction mechanism and measure the catalysts’catalytic activity. The catalysts used in the CO oxidation reaction can be sorted into two categories, precious metal catalysts and non-precious metal catalysts. Precious metal catalysts, such as Au, Pt, Pd and Ru, show high catalytic activity and simutaniously has strong stability, but they are too expensive other for industrial production or for experiental study. So many attentions are payed to the non-prescious metal catalysts, the copper-based catalyst and the cobalt-based catalyst, which are more available and can been got at low prices. In this study, copper catalysts were prepared and were modified by adding additives or pretreating the carrier with organic solvent, and then a comparative study was conducted:the additional effect of Ce, Mn and Fe oxides on the reference catalyst CuO/SiO2; the modification of organic solvents (ethylene glycol, N-butyl alcohol, glycerol, dipropylene glycol) on the reference catalyst CuO/SiO2; the joint effect of additive (CeO2, MnO2, Fe2O3) and ethylene glycol on the reference catalyst CuO/SiO2; the effect of calcination temperature on the catalysts’catalytic activity. The catalysts’ avtivity were evaluated by CO oxidation reaction and the catalysts’ microscopic structures were characterized by means of BET, XRD, TPR, XPS, In-Situ DRIFT. And we concluded as follows:among CeO2, MnO2and Fe2O3, CeO2has the most promotional effects and CuO/CeO2-SiO2realize complete conversion of CO at433K, which is120K lower than the reference catalyst CuO/SiO2. The promotional effects of various added oxides are in order of CeO2>MnO2>Fe2O3, due to the CeO2promoted to forming more both Cu+species and lattice oxygen species on the surface of the catalysts; the solvents can change the surface structure of the carrier SiO2enhancing the interaction of the copper active sites and the carrier leading to the higher dispersion of the the active sites, thus improving the catalytic activity of the catalysts; when adding the additive and jointly pretreating the carrier with EG, for each additive, the catalyst’s activity increase with the amount of the additive, but the pretreatment effect of EG is less pronounced or disappear when the additive amount increased to15%, which can been explained as, the modified effect of additives and ethylene glycol can not be superimposed.