A novel four-way combining catalysts containing double layers was applied to simultaneously remove four kinds of exhaust pollutants （NOx, CO, HC and PM） emitted from diesel engine. The four-way catalysts were charac...A novel four-way combining catalysts containing double layers was applied to simultaneously remove four kinds of exhaust pollutants （NOx, CO, HC and PM） emitted from diesel engine. The four-way catalysts were characterized using scanning electron microscope （SEM） and Ultraviolet visible diffuse reflectance spectroscopy （UV-Vis DRS）. Their catalytic performances were evaluated by temperature-programmed reaction technology. The double layer catalysts could effectively remove the four main pollutants. The highest catalytic activity was given by the two-layered catalysts of La0.6 K0.4CoO3/Al2O3 and W/HZSM-5. Under the simulated exhaust gases conditions, the peak temperature of the soot combustion was 421℃, the maximal conversion of NO to N2 was 74%, the temperature of the HC total conversion was 357℃, and the maximum conversion ratio of CO was 99%.展开更多
The use of non-noble nickel-based catalysts for low temperature CO methanation has been a challenge in recent years.Herein,MgAl layered double oxides sample with high dispersion synthesized by a facile N-(2-Hydroxyeth...The use of non-noble nickel-based catalysts for low temperature CO methanation has been a challenge in recent years.Herein,MgAl layered double oxides sample with high dispersion synthesized by a facile N-(2-Hydroxyethyl)ethylenediaminetriacetic acid assisted wetness impregnation approach,demonstrates much superior catalytic activity and exceptional stability for CO methanation in comparison with the classical Ni/MgAl-LDO catalyst prepared by the ordinary wetness impregnation method.HRTEM results showed that N-(2-Hydroxyethyl)ethylenediaminetriacetic acid played a positive role in the dispersion of Ni,as well as Ni-support interaction.Well-dispersed Ni particles with a size of about 5 nm were formed in the presence of N-(2-Hydroxyethyl)ethylenediaminetriacetic acid.Compared to the Ni/MgAl-LDO prepared by conventional impregnation method,the NH-Ni/MgAl-LDO exhibited superior catalytic performance,especially excellent thermal stability.The NH-Ni30/MgAl-LDO catalyst was found to keep a 70%CO conversion even at 160◦C which demonstrates its good low temperature performance.From the in situ FTIR observations,this good performance at low temperatures may be linked to the delocalization of electrons around CO caused by surface hydroxyl groups.展开更多
基金supported by the Hi-Tech Research and Development Program (863) of China (No.SQ2009AA06Z313)the National Natural Science Foundation of China (No. 20803093,20833011)+1 种基金the Doctor Selected Foundation for the University of State Education Ministry of China (No. 200804251016)the Beijing Outstanding Ph.D Thesis Foundation (No. YB20091141401)
文摘A novel four-way combining catalysts containing double layers was applied to simultaneously remove four kinds of exhaust pollutants （NOx, CO, HC and PM） emitted from diesel engine. The four-way catalysts were characterized using scanning electron microscope （SEM） and Ultraviolet visible diffuse reflectance spectroscopy （UV-Vis DRS）. Their catalytic performances were evaluated by temperature-programmed reaction technology. The double layer catalysts could effectively remove the four main pollutants. The highest catalytic activity was given by the two-layered catalysts of La0.6 K0.4CoO3/Al2O3 and W/HZSM-5. Under the simulated exhaust gases conditions, the peak temperature of the soot combustion was 421℃, the maximal conversion of NO to N2 was 74%, the temperature of the HC total conversion was 357℃, and the maximum conversion ratio of CO was 99%.
基金National Natural Science Foundation of China(No.22068034)International Science and Technology Cooperation Project of Shihezi University(No.GJHZ201804)+1 种基金International Science and Technology Cooperation Project of Bingtuan(No.2018BC002)Science and Technology Innovation Talents Program of Bingtuan(No.2019CB025).
文摘The use of non-noble nickel-based catalysts for low temperature CO methanation has been a challenge in recent years.Herein,MgAl layered double oxides sample with high dispersion synthesized by a facile N-(2-Hydroxyethyl)ethylenediaminetriacetic acid assisted wetness impregnation approach,demonstrates much superior catalytic activity and exceptional stability for CO methanation in comparison with the classical Ni/MgAl-LDO catalyst prepared by the ordinary wetness impregnation method.HRTEM results showed that N-(2-Hydroxyethyl)ethylenediaminetriacetic acid played a positive role in the dispersion of Ni,as well as Ni-support interaction.Well-dispersed Ni particles with a size of about 5 nm were formed in the presence of N-(2-Hydroxyethyl)ethylenediaminetriacetic acid.Compared to the Ni/MgAl-LDO prepared by conventional impregnation method,the NH-Ni/MgAl-LDO exhibited superior catalytic performance,especially excellent thermal stability.The NH-Ni30/MgAl-LDO catalyst was found to keep a 70%CO conversion even at 160◦C which demonstrates its good low temperature performance.From the in situ FTIR observations,this good performance at low temperatures may be linked to the delocalization of electrons around CO caused by surface hydroxyl groups.
