Preparation,Modification And Properties Of W,V/Ce,Ti Metal Oxide Deno_x Catalysts With Good Sulfur Resistance At Low Temperature

The industrial process is accelerating and the environmental pollution is serious.The environmental protection issue has not only been confined to a certain country,but has become a problem that the global community needs to jointly face and pay attention to.Air pollution is an important environmental issue that cannot be ignored,and nitrogen oxides are the major air pollution.Things are gradually being taken seriously.At present,NH3-SCR denitrification is a relatively mature and extensive technology for the treatment of NOx.In this experiment,a metal oxide catalyst for the NH3-SCR process was studied,that is cerium-titanium mixture oxide catalysts.The effects of preparation methods,mole ratio of cerium to titanium,and calcination temperature on the catalytic performance of CenTiOx catalyst were investigated.The different preparation method was found not significant to the NO conversation of catalyst.The Ce0.3TiOx catalyst prepared by sol-gel method has better performance,and the selectivity of nitrogen can reach above 95%.While the surface area of the catalyst decreases obviously with the increase of the molar ratio of cerium to titanium.When the molar ratio of cerium to titanium is 0.5,the catalyst activity is best.Then,the catalyst were modified with loading vanadium and the preparation of the core-shell structure catalyst.The loading of vanadium had a positive influence on the low-temperature activity of the Ce0.5TiOx catalyst.With the increase of the vanadium loading,the low-temperature activity of the catalyst showed an upward trend,but at the same time the high temperature activity of the catalyst is lost and the nitrogen selectivity decreases.Although there is a certain increase for the activity of the catalysts loaded with tungsten at the low temperature,the high temperature activity of the Ce0.5TiOx catalyst is seriously affected,and the NO conversion drops rapidly.The Ce-Ti core-shell structure catalyst has a great influence on the performance,but it has a negative influence on the low temperature activity and exhibits a good activity at high temperature.Since the sulfur resistance is an important indicator of whether the catalyst can be used industrially,the sulfur resistance of the 5V%/Ce0.5TiOx catalyst was examined.When sulfur was introduced,the NO conversion decreased suddenly,but it returned to 100%after a few hours,and stay weak again after ten hours to 86%to remain stable.The 5%V2O5/CeZrO4 prepared by the impregnation method showed excellent sulfur resistance.The catalyst retained good catalytic activity and nitrogen selectivity within 110 hours,and then the NO conversion quickly weakened to 60%.