Loading strategy for the active components of monolithic catalyst and its influences on the microwave enhanced catalytic combustion of toluene

Aiming at solving the shedding problem of active components, a loading strategy that includes carrier pretreatment and addition of silica sol was adopted to strengthen the combination of the active components with the carrier. Catalytic activity of the catalyst was investigated in toluene combustion by using microwave single-mode cavity, and high-firmness catalysts were characterized subsequently. The study showed that the shedding rate of Cu-Mn-Ce(silica sol)/cordierite honeycomb(CH) catalyst prepared under conditions of 10% hydrochloric acid pretreatment at room temperature and 0.125 of the mass ratio of silica sol to water absorption amount of CH carrier was 0.0129%, which was much lower than 0.950% of Cu-Mn-Ce/CH catalyst. Cu-Mn-Ce(silica sol)/CH catalyst had smaller active particles, larger specific surface area and more active crystals than Cu-Mn-Ce/CH catalyst. Under conditions of 1000 mg/m³ of initial concentration, 0.12 m³/h of air flow, 200 W of microwave power and 350 ℃ of bed temperature, the removal and mineralization rates of toluene by Cu-Mn-Ce(silica sol)/CH catalyst were 98.5% and 87.9%, respectively. The Cu-Mn-Ce(silica sol)/CH catalyst owned high catalytic activity and stability after 43 h run, and the shedding rate of active components was 0.0328%. The addition of silica sol could enhance the interaction forces between the active components and the catalyst carrier, and the formation of siloxane chemical bonds could greatly improve the connection of active components to prolong the service life of the catalyst.