Catalytic Decomposition of CFC-12 over Solid Super Acid Mo_2O_3/ZrO_2

摘要

Catalytic decomposition of dichlorodifluoromethane (CFC-12) in the presence of water vapor and oxygen was studied over a series of solid super acids Mo_2O_3 /ZrO_2 that had different ZrO_2 content by using a fixed-bed reactor. CO_2 and CClF_3 were the main products and no CO was detected as by-product. The decomposition activity of solid super acid largely depended on the content of ZrO_2 and the calcination temperatures of Mo_2O_3 /ZrO_2. The optimal calcination temperature and content of ZrO_2 for preparing Mo_2O_3 /ZrO_2 with the highest activity for catalytic decomposition of CFC-12 were 450°C and 20–40 wt %, respectively. Adopting a low concentration of oxygen and CFC-12 together with a high concentration of water vapor was preferable for having the high conversion efficiency of CFC-12 and the selectivity for CO_2. The catalytic activity of Mo_2O_3 /ZrO_2 remained steady for 100 h in continuous operation.