Promotional Effects of Transition Metal Modification over Al2O3 for CH3SH Catalytic Oxidation

Abstract

AbstractIn this work, a series of metal‐modified alumina catalysts by ultrasonic‐assisted were prepared and the activity for the CH3SH catalytic oxidation were evaluated. The investigation shown that metal‐modified alumina catalysts could obviously promote the conversion of CH3SH. The activity by different metal‐modified alumina catalysts decreased in turn: 15%Cu‐Al2O3 > 15%Fe‐Al2O3 > 15%Mn‐Al2O3 > 15%Ce‐Al2O3 > 15%Co‐Al2O3 > Al2O3.The catalysts were characterized in comprehensive by X‐ray diffraction (XRD), adsorption‐desorption isotherms of N2, hydrogen temperature‐programmed reduction (H2‐TPR), carbon dioxide temperature‐programmed desorption (CO2‐TPD) and ammonia temperature‐programmed desorption (NH3‐TPD). We found that more surface oxygen species were formed on the metal‐modified alumina catalysts, and this feature can improve the catalytic activity of the catalysts. On the basis of the characterization results, the number of weak and middle basic sites were increased by the metal (Cu, Fe, Co, Ce and Mn) modified Al2O3, which were enhanced the high acid CH3SH adsorption. At the same time, the optimal loading amount of Cu was 15%. Based on the above analysis, a possible reaction mechanism of catalytic oxidation of CH3SH by Cu‐Al2O3 was proposed.