Microwave-assisted Preparation Of Thermal-resistant Pt/CeO₂ Catalyst For NO Reduction During CO-SCR Process

Waste incineration is now one of the most widely methods for waste disposal,but it will produce a large number of air pollutants with CO and NO as the main components endangering the ecological environment and human health.Therefore,more and more attention has been paid to the removal of CO and NO.However,conventional catalyst will be easily inactivated in high-temperature flue gas,so high temperature resistant catalysts are needed to be prepared.In this study,the Pt/CeO₂ catalysts applied for CO-SCR technology were prepared by atom trapping impregnation method,within the Pt as the active component and the CeO₂ as the support.The effects of preparation conditions of catalyst and reaction operation conditions were discussed in detail.On the other hand,the microwave-assisted were used for catalysts calcination to discuss the microwave irradiation on the optimization of catalytic performance.The catalysts were characterized by means of XRD,BET,TEM,SEM,N₂ adsorption-desorption and H₂-TPR at the same time.The main results were shown as follows:?1?Pt/CeO₂ were first used for CO oxidation.When the loading amount of Platinum was 1%,the catalytic performance of catalyst was best for CO oxidation,1%Pt/CeO₂ has the largest specific surface area and the best dispersion according to the BET results.And the optimum GSHV was 100×10^³h^-1 and the optimum oxygen content was 6%O₂ in the reaction of CO oxidation.In addition,from the analysis of SEM and BET,it can be seen that the specific surface area of the catalyst prepared by conventional impregnation method?WI?decreased after the continuous high temperature CO reaction,and the structure of Pt/CeO₂?WI?were collapsed.Another,Pt/CeO₂ by atom trapping impregnation method?AT?was an effective method to prepare high temperature resistant catalysts because it can improve the high temperature stability.?2?Pt/CeO₂ were used for CO-SCR reaction next.The optimum GSHV was still100×10^³h^-1 after adding NO,but the optimum O₂ content changed to 9%owing to the CO and NO competitive adsorption with O₂ in the CO-SCR reaction.In addition,the higher CO concentration will lead to the CO self-inhibition and affect CO reduction of NO,therefore the best ratio of CO:NO was 2:1 in this study.?3?When using microwave technology?MW?to calcinate catalysts,the temperature range for catalytic conversion of NO was clearly broaden.The results of XRD?H₂-TPR and N₂ adsorption and desorption tests showed that the microwave-assisted calcination increasing the crystallization of catalysts,and improving the Pt dispersion on the CeO₂ support,meanwhile,enhancing the redox performance of Pt/CeO₂?MW?.On the other hand,the Pt/CeO₂?MW?can almost maintain its initial catalytic activity in repeated reaction tests.In general,microwave calcination can enhance the activity life of catalyst and promote the optimization of catalyst performance.