Catalytic Combustion Of Soot Particles Over Tin-based Oxide Catalysts

The diesel engine has the advantage of low fuel consumption,high power and stability,and is widely used in industrial engines.However,exhaust gas have a serious impact on natural environments and human health.Catalytic soot particulate filtration capture is currently removing the most effective way to remove soot particulate,the key point of this technology is the development and application of low temperature catalysts.Tinium oxide has good chemical stability and thermal stability,and has good oxygen oxygen oxygenation properties and catalytic performance,which is widely used in CO oxidation,photosensitive materials,and catalytic soot combustion.The doping of the transition metal oxide can improve the structural characteristics of SnO₂,and improve the activity of the catalyst.In this work,prepared tin-based oxide solid solution by CTAB assisted sol-gel method and CTAB assisted coprecipitation method.A variety of techniques are used to characterize the physical chemistry properties of the catalyst,and with a catalytic soot particulate as a reaction model,exploring the constructive relationship and reaction mechanism between tin-based oxide solid solution catalyst catalyst and physical chemical properties.A series of SnO₂ catalysts（900SnO₂、800SnO₂、700SnO₂ and 600SnO₂）with different tempetature calcination were successfully synthesized using the CTAB-assisted co-precipitation method.The 800SnO₂ and 900SnO₂ two sample peaks sharp,the peak intensity is significantly higher than 700SnO₂ and 600SnO₂,which means that the first two crystal phase crystallinity is higher.Also explained the process of calcination crystals of the SnO₂ catalyst,the higher the temperature in a certain range,the better the temperature in a certain range.900SnO₂ has a specific surface area of 12.7 m²/g,a pore diameter of 31 nm.Different temperature calcination causes the SnO₂ lattice to produce more surface lack oxygen,improve the oxidative reducing performance of the SnO₂ oxide,providing a large number of active sites for catalytic carbon smoke.The SnO₂ catalyst was carried out under an O₂atmosphere to catalyze carbon smoke combustion experiments,and found that four catalysts had good catalytic activity.Further,the SnO₂ oxide is good attributed to its unique mesh structure,a higher oxygen empty concentration and a good low temperature redox property.The Mn、Fe、Co and Ni transition metal doped SnO₂ solid solutions were prepared by the CTAB-assisted co-precipitation method.High temperature calcination rear solid oxide remained relatively large surface area（20～40 m²/g）,and the transition metal doping increases the aperture size（the most capable diameter of 20～30 nm）.There is a strong interaction between the transition metal and the Snin the solid solution,and the mobility of surface oxygen and oxidation reducing properties are improved.The SnO₂ prepared by this study has a good soot particulate catalytic combustion activity,and the activity and selectivity of the tin-based solid solution after the transition metal doping is further improved,and the soot particulate combined rate is accelerated,this is related to its increased oxidative capacity,increasing surface oxygen space,and improved well structural properties.The relationship between carbon oxidation and NO oxidative activity in the tin-based solid solution confirmed the promotion of NO₂auxiliary soot combustion.The Mnand Ce doped tin-based solid solutions MnCe Sn,MnSn,Ce Snand SnO₂ were successfully prepared by CTAB-assisted co-precipitation.The solid solution oxide remains relatively larger surface area（20～40 m²/g）,and the most capable diameter of Mncesn and MnSnis 30 nm and 31 nm,respectively.Mnand Ce doping improve the mobility and redox properties of SnO₂,and produces a large amount of oxygen space and a lack oxygen,providing a large number of active sites for catalytic soot combustion.The catalytic activity under the NO+O₂ atmosphere was significantly better than the catalytic activity under the O₂atmosphere,confirmed NO_x auxiliary combustion mechanism.