Synthesis Of Cu Based Bimetallic MOFs Catalysts And Their CO-SCR Catalytic Properties

The emission of Nitrogen oxides（NOx）can cause many environmental pollution incidents such as acid rain and photochemical smog,which is harmful to human health and ecological environment.At present,due to NOx emission increase continuously with the development of economy in our country,NOx pollution control is becoming an issue to be solved in China’s environmental field.Among many NOx removal methods,the selective catalytic reduction（SCR）has been proved as the most widely-used and effective denitrification technology.Different types of reductants,e.g.ammonia,CO,H₂ or hydrocarbons were employed in this reaction.Among them,CO-SCR technology has become an important research trend because it possesses long catalyst life and can remove both CO and NOx pollutants simultaneously.For CO-SCR technology,the development and selection of catalysts is the key factor to determine the denitrification performance of this reaction.Metal-organic frameworks（MOFs）has been widely studied in the field of catalysis owing to their high surface area,abundant active sites and strong stability.However,to the best of our knowledge,the efficient CO-SCR catalysts based on MOFs have been seldom explored.Therefore,bimetallic Cu-Al-BTC and Cu-Mn-BTC MOFs were synthesized and applied in CO-SCR in this study.The synergistic catalytic effect between different ions was utilized to improve the denitrification efficiency of CO-SCR reaction.At the same time,the physicochemical properties of the catalysts and the reaction process were studied by a series of characterization methods.The main results are as follows:（1）Bimetallic Cu-Al-BTC MOFs were synthesized successfully via a hydrothermal method,and the synthetic conditions including Cu/Al ratio and activation temperature was optimized.The Cu-Al-BTC catalyst with Cu/Al ratio of6:1 and the activation temperature of 220^℃ achieves the best CO-SCR catalytic performance,with its NO conversion reaches to nearly 100%in the temperature range of 300-375^℃.Compared with Cu-BTC,bimetallic 6Cu1Al-BTC catalyst achieves a maximum increase of about 60%in NO conversion.（2）The XRD,SEM,EDX results showed that Cu-Al-BTC MOFs has regular crystal structure and morphology,and the XPS and H₂-TPR results proved that Cu²⁺/Cu⁺were the main active species.The synergistic effect between Cu and Al ions can enhance the catalytic activity of bimetallic Cu-Al-BTC catalysts.（3）Cu-Mn-BTC catalyst was prepared by hydrothermal method and applied in CO-SCR reaction.After optimizing the synthetic conditions,it came to the conclusion that with Mn（Cl）₂ as precursor,Cu/Mn ratio of 2:1,after vacuum drying at 200^℃,2Cu1Mn（Cl）catalyst could exhibit the maximum NO removal efficiency.At280-340^℃,this catalyst achieves more than 90%NO conversion,and it has strong thermal stability which can keep stable until 340^℃.