INFLUENCE OF Pt ON THE PROPERTIES AND ACTIVITY OF CuO-BASED CATALYSTS FOR LOW TEMPERATURE OXIDATION OF CARBON MONOXIDE

Abstract

A series of mono-oxide and multi-oxide catalysts: 10 wt.%CuO/γ-Al₂O₃; 10 wt.%CuO +10 wt.%Cr₂O₃/γ-Al₂O₃; 10 wt.%CuO + 20 wt.%CeO₂/γ-Al₂O₃, and 10 wt.%CuO + 10 wt.%Cr₂O₃ +20 wt.%CeO₂/γ-Al₂O₃ have been prepared and modified by Pt with contents from 0.05 up to 0.3 wt.%. Physico-chemical properties of the catalysts were determined by the methods of BET N₂- Adsorption, Hydrogen Pulse Chemisorption (HPC), XRD, TPR, EDS and IR-CO adsorption. The oxidative activity of the catalysts was studied at the temperature range 75 - 300 ^oC and CO concentration of 0.5 mol.%. Addition of Pt led to weakening of the interaction between CuO and Al₂O₃, CuO and Cr₂O₃ that enhanced the reducibility of CuO, resulting in increase of activity of CuAl, CuCeAl and CuCrCeAl catalysts. Meanwhile, due to the reduction of CuCr₂O₄ formation, the activity of catalysts CuCrAl decreased. The catalyst sample CuCeAl, containing 0.1 wt.% Pt, has been shown to be the best one for the complete oxidation of CO. At the given conditions on this catalyst the complete oxidation of CO to CO₂ occurred at 125 ^oC and space velocity 75,000 h^-1 .