Electrochemical Preparation Of MOF (Cu)-based Composite Catalysts And Its Catalytic Activities For CO Oxidation

MOFs was developed by transition-metal ions and organic ligands,for the characters of morphologic symmetry properties,high porosity,high surface area and unique pore structure,they were widely used in areas of gas storage and separation,drug delivery and catalysis.The conventional methods for the synthesis of MOFs mainly contained hydrothermal method,microwave synthesis and RT stirring,few reports available based on electro-synthesis of MOFs and their catalytic applications.Electrochemical route had many advantages such as more efficient,easy to operate and environmental friendly,therefore,we synthesized HKUST-1(one of Cu-based MOFs materials)by electrochemical route,and TiO2-CuxO catalysts were subsequently prepared by using HKUST-1 as template.All catalysts were tested by probe reaction of CO oxidation and were characterized by XRD,TGA,SEM,TEM,CO-TPD,H2-TPR,ICP and other techniques to reveal the relationship between structure and properties.The main research summaries were as follows:1.We synthesized HKUST-1 by electrochemical method and further investigated the effect of activation temperature on the structure and catalytic performance of HKUST-1.The results indicated that HKUST-1 with high thermal stability was successfully synthetized when the applied voltage was chosen 15 V and reaction time was for 2 h;When increasing the activation temperature,its catalytic performance became better,the optimized temperature was 300 ?.The reason was that 300 ? favored thoroughly removal of coordinated water,resulting in increasing of Cu+,where CO molecules could chemically adsorbed and be oxided.2.TiO2-CuxO catalysts were prepared by using HKUST-1 as template.The optimal calcination temperature of TiO2-CuxO catalysts was investigated.The results revealed that the catalytic activity increased at first but later decreased with increasing calcination temperature from 240 ? to 420 ?.When the calcination temperature reached 360 ?,the catalytic activity for TiO2-CuxO-360 was excellent.The reason was that the components of Cu' and Ti were separated with each other and the interaction became enhanced,resulting in difficulty for agglomeration and improvement of reducibility.In addition,more content of basic sites exposed on the catalyst that allowed CO molecules to coordinate at the metal sites,which activated the molecules of CO and promoted the oxidation reaction.3.The influence of the additives on the structure and catalytic performance of TiO2-CuxO catalyst was investigated.It was found that effect of additives was significantly different,the catalytic activities of different additives increased in the order Ce>Co>Mn.The activity for CO oxidation was significantly enhanced by the addition of Ce.With Ti/Ce=1,CO was completely converted when the reaction temperature was 110 ?.The reason was that Ce promoted dispersion of low valence Cu species,which enhanced the reducibility and synergy interaction among the components,as a result,the catalytic activity was significantly increased.