Platinum/cerium-zirconium-sulfate（Pt/Ce-Zr-SO_4^（2-）） catalysts were prepared by wetness impregnation.Catalytic activities were evaluated from the combustion of propene and CO.Sulfate（SO_4^（2-））addition improv...Platinum/cerium-zirconium-sulfate（Pt/Ce-Zr-SO_4^（2-）） catalysts were prepared by wetness impregnation.Catalytic activities were evaluated from the combustion of propene and CO.Sulfate（SO_4^（2-））addition improved the catalytic activity significantly.When using Pt/Ce-Zr-SO_4^（2-） with 10 wt%SO_4^（2-）,the temperature for 90%conversion of propene and CO decreased by 75℃ compared with Pt/Ce-Zr.The conversion exceeded 95%at 240℃ even after 0.02%sulfur dioxide poisoning for 20 h.Temperature-programmed desorption of CO and X-ray photoelectron spectroscopy analyses revealed an improvement in Pt dispersion onto the Ce-Zr-SO_4^（2-） support,and the increased number of Pt particles built up more Pt^（-）-（SO_4^（2-））^（-） couples,which resulted in excellent activity.The increased total acidity and new Bronsted acid sites on the surface provided the Pt/Ce-Zr-SO_4^（2-） with good sulfur resistance.展开更多
Two continuously regenerating diesel particulate filter （CRDPF） with different configurations and one particles oxidation catalyst （POC） were employed to perform experiments in a controlled laboratory setting to e...Two continuously regenerating diesel particulate filter （CRDPF） with different configurations and one particles oxidation catalyst （POC） were employed to perform experiments in a controlled laboratory setting to evaluate their effects on NO2, smoke and particle number emissions. The results showed that the application of the after-treatments increased the emission ratios of NO2/NOx significantly. The results of smoke emissions and particle number （PN） emissions indicated that both CRDPFs had sufficient capacity to remove more than 90% of total particulate matter （PM） and more than 97% of solid particles. However, the POC was able to remove the organic components of total PM, and only partially to remove the carbonaceous particles with size less than 30 nm. The negligible effects of POC on larger particles were observed due to its honeycomb structure leads to an inadequate residence time to oxidize the solid particles or trap them. The particles removal efficiencies of CRDPFs had high degree of correlations with the emission ratio of NO2/NOx. The PN emission results from two CRDPFs indicated that more NO2 generating in diesel oxidation catalyst section could obtain the higher removal efficiency of solid particles. However this also increased the risk of NO2 exposure in atmosphere.展开更多
A series of Pt-V/Ce-Zr-O diesel oxidation catalysts was prepared using the impregnation method. The catalytic activity and sulfur resistance of Pt-V/Ce-Zr-O were investigated in the presence of simulated diesel exhaus...A series of Pt-V/Ce-Zr-O diesel oxidation catalysts was prepared using the impregnation method. The catalytic activity and sulfur resistance of Pt-V/Ce-Zr-O were investigated in the presence of simulated diesel exhaust. The effect of vanadium on the structure and redox properties of the catalysts was also investigated using the Brunauer-Emmett-Teller method,X-ray diffraction, H2temperature-programmed reduction, CO temperature-programmed desorption, X-ray photoelectron spectroscopy, and Energy Dispersive Spectroscopy. Results showed that the Pt particles were well dispersed on the Ce-Zr-O carrier through the vanadium isolation effect, which significantly improved the oxidation activity toward CO and hydrocarbons. An electron-withdrawing phenomenon occurred from V to Pt, resulting in an increase in the metallic nature of platinum, which was beneficial to hydrocarbon molecular activation.展开更多
Decomposition mass loss and pyrolysis products analyses of particles sampled at various locations along the tailpipe of a Euro-IV diesel engine were performed using a thermo gravimetry in conjunction with Fourier tran...Decomposition mass loss and pyrolysis products analyses of particles sampled at various locations along the tailpipe of a Euro-IV diesel engine were performed using a thermo gravimetry in conjunction with Fourier transformation infrared spectrometrymass spectrum.Diesel particles were collected at the same location with and without diesel oxidation catalyst(DOC)mounted on the test engine separately.The three poles in thermal gravity-differential thermal gravity images suggested that the decomposition process of diesel particles could be divided into three stages which correspond to the decompositions of lower boiling substances,higher boiling substances and soot respectively.It is noticed that no matter whether DOC was mounted or not,the further the particles were sampled away from the engine block,the lower the peak temperatures and the heavier the mass losses within the first two stages,which indicated that the soluble organic fraction in the particle samples increased and therefore lowering the activation energy of thermal decomposition.Hydroxyl,ammonia,C_xH_y fragments,benzene,toluene,and phenol were found to be the primary products of particle decomposition,which didn’t change with the location of particle sample point.The employment of DOC increased the activation energy for particle oxidation and resulted in a higher peak temperature and lower mass loss within the first-stage.Moreover,the C=O stretching bands of aldehyde and ketone at 1771 cm-1 was only detected without a DOC,while the N02 peak at 1634 cm-1 was solely noticed with the presence of DOC.Compared to the first-stage pyrolysis products,more polycyclic aromatic hydrocarbons and less C_xH_y fragments were seen in the second-stage.展开更多
The V-K catalysts were produced on porous α-alumina substrate by a solution impregnation route and the compositions and catalytic activities for soot oxidation were studied by XRD, TG/DTG, DSC and TPR. According to t...The V-K catalysts were produced on porous α-alumina substrate by a solution impregnation route and the compositions and catalytic activities for soot oxidation were studied by XRD, TG/DTG, DSC and TPR. According to the catalytic activity studies, the catalytic activity of the crystalline phases is in the order： KNO3＋KVO3〉K3V5O14＋KVO3. The appearance of excessive KHCO3 phase will lead to the deterioration of catalytic activity when the catalysts contain higher KNO3 content. It is also found that when the K∶V molar ratio is higher than 1∶1, the prepared catalysts show a strong CO2 absorption characteristic and this behavior will become gradually significant with the increasing of K∶V molar ratio. Considerable amount of absorbed CO2 are strongly bonded to the crystal lattice with onset desorption temperature of 200 ℃.展开更多
Diesel soot is related to incomplete fuel oxidation, and possesses the well-known mutagenic effects on human health.Diesel soot was collected from diesel engines and oxidized in laboratorial micro reactor by several p...Diesel soot is related to incomplete fuel oxidation, and possesses the well-known mutagenic effects on human health.Diesel soot was collected from diesel engines and oxidized in laboratorial micro reactor by several prepared rare earth-based catalysts with or without different harmful monoxide gases such as NO, and activities of several rare earth catalysts were studied.The results indicate that soot can be more easily oxidized with monoxide gases.展开更多
A series of Ce_(1-x)Ti_(x)O_(2)mixed oxide catalysts were synthesized by sol-gel method and then loading of noble metal(M=Pt,Rh,Ru)was used for soot oxidation.Ti-doped Ce_(1-x)Ti_(x)O_(2)catalysts(x is the molar ratio...A series of Ce_(1-x)Ti_(x)O_(2)mixed oxide catalysts were synthesized by sol-gel method and then loading of noble metal(M=Pt,Rh,Ru)was used for soot oxidation.Ti-doped Ce_(1-x)Ti_(x)O_(2)catalysts(x is the molar ratio of Ti/(Ti+Ce)and ranges from 0.1 to 0.5)exhibit much better oxidation performance than CeO_(2)catalyst,and the Ce_(0.9)Ti_(0.1)O_(2)catalyst calcined at 500℃has the best catalysis activity.Each noble metal(1 wt%)was supported on Ce_(0.9)Ti_(0.1)O_(2)(M/C9 T1)and the properties of the catalysts were characterized by X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),Raman,Brunauer-Emmett-Teller(BET)method,and H_(2)-temperature programmed reduction(H_(2)-TPR)results.Results show that the introduction of Ti into CeO_(2)forming Ti-O-Ce structure enhances the catalytic activity and increases the number of oxygen vacancies at the catalyst surface.The noble metal is highly dispersed over Ce_(0.9)Ti_(0.1)O_(2),and M/C9 T1 catalysts present enhanced activity in comparison to Ce_(0.9)Ti_(0.1)O_(2).It is found that noble metals can greatly increase the activity of the catalyst and the corresponding oxidation rate of soot can enhance the electron transfer capacity and oxygen adsorption capacity of the catalyst.A small amount of Ti doping in CeO_(2)can significantly improve the activity of the catalyst,while a large amount of Ti reduces the performance of the catalyst because a large amount of Ti is enriched on the surface of the catalyst,which hinders the contact and reaction between the catalyst and the soot.展开更多
An ultrasound-assisted heterogeneous catalytic oxidation process was applied to eliminate sulfur from commercial diesel fuel oil.The studied variables were catalyst concentration,type of catalyst(homogeneous or hetero...An ultrasound-assisted heterogeneous catalytic oxidation process was applied to eliminate sulfur from commercial diesel fuel oil.The studied variables were catalyst concentration,type of catalyst(homogeneous or heterogeneous),oxidizing agent concentration,and the application of ultrasound energy.Supported catalysts were prepared by impregnation of coal fly ash with an iron(Ⅱ)sulfate aqueous solution using ultrasound energy.After drying,the catalyst was calcined at 500℃for 4 h.The oxidizing agent was hydrogen peroxide.Ultrasound energy was applied with a frequency of 47 kHz and an intensity of 147 W.Ethanol was employed for extracting the oxidized compounds from the hydrocarbon mixture.Coal fly ash and ethanol were used with the purpose of applying low-cost raw materials in chemical processes.It was found that under the studied conditions,increasing oxidizing agent concentration and the application of ultrasound energy can enhance the sulfur removal from commercial diesel fuel oil.Catalyst concentration did not play a significant role in the process.Similar results were obtained using homogeneous or heterogeneous catalyst,which is important since the heterogeneous catalyst could be recovered,reactivated,and used in many cycles.展开更多
Diesel oxide catalysts and soot combustion catalysts were reported in this paper.The former was manufactured in mass last year, and enhanced performance is under development now.The later is screened out and further r...Diesel oxide catalysts and soot combustion catalysts were reported in this paper.The former was manufactured in mass last year, and enhanced performance is under development now.The later is screened out and further research is under way.The best soot combustion catalyst could ignite soot combustion even at 350 ℃, which is within the range of temperatures reached in diesel exhaust, and shows the catalytic combustion velocity nearly one time faster compared with non-catalytic combustion of soot, which is of benefit to rapid regeneration of diesel particulate filter, thus it might be an excellent practicable catalyst.展开更多
In order to reduce oxides of nitrogen （NOx） emanated from a diesel engine, a comprehensive urea selective catalyst reduction （SCR） DeNOx catalyst was modeled in which numerical simulations were used as a complemen...In order to reduce oxides of nitrogen （NOx） emanated from a diesel engine, a comprehensive urea selective catalyst reduction （SCR） DeNOx catalyst was modeled in which numerical simulations were used as a complementary tool for the experimental investigations to make the design decisions, and hence shorten the de- velopment process. In this approach, relevant conversion reactions were studied in 1D model, and the parame- ters obtained in this way were transferred to 3D simulations. According to the results of the study, the conver- sion of NO and NO2 increased with the increase in monolith solid temperature. With the increase in the ratio of NO2/NOx the conversion of NO, NO2 and NOx increased resulting in maximum reduction of NOxat the ratio of 1; beyond this ratio, the conversion of NO2 and NOx decreased; however, NO continued to be converted till the ratio was 1.8. The conversion of NOx decreased with the increase in space velocity.展开更多
基金supported by the National Natural Science Foundation of China(21506194,21676255)the Provincial Natural Science Foundation of Zhejiang Province(LY16B070011)the Commission of Science and Technology of Zhejiang Province(2017C33106,2017C03007)~~
文摘Platinum/cerium-zirconium-sulfate（Pt/Ce-Zr-SO_4^（2-）） catalysts were prepared by wetness impregnation.Catalytic activities were evaluated from the combustion of propene and CO.Sulfate（SO_4^（2-））addition improved the catalytic activity significantly.When using Pt/Ce-Zr-SO_4^（2-） with 10 wt%SO_4^（2-）,the temperature for 90%conversion of propene and CO decreased by 75℃ compared with Pt/Ce-Zr.The conversion exceeded 95%at 240℃ even after 0.02%sulfur dioxide poisoning for 20 h.Temperature-programmed desorption of CO and X-ray photoelectron spectroscopy analyses revealed an improvement in Pt dispersion onto the Ce-Zr-SO_4^（2-） support,and the increased number of Pt particles built up more Pt^（-）-（SO_4^（2-））^（-） couples,which resulted in excellent activity.The increased total acidity and new Bronsted acid sites on the surface provided the Pt/Ce-Zr-SO_4^（2-） with good sulfur resistance.
基金supported by the National Natural Science Foundation of China (No. 50876013)
文摘Two continuously regenerating diesel particulate filter （CRDPF） with different configurations and one particles oxidation catalyst （POC） were employed to perform experiments in a controlled laboratory setting to evaluate their effects on NO2, smoke and particle number emissions. The results showed that the application of the after-treatments increased the emission ratios of NO2/NOx significantly. The results of smoke emissions and particle number （PN） emissions indicated that both CRDPFs had sufficient capacity to remove more than 90% of total particulate matter （PM） and more than 97% of solid particles. However, the POC was able to remove the organic components of total PM, and only partially to remove the carbonaceous particles with size less than 30 nm. The negligible effects of POC on larger particles were observed due to its honeycomb structure leads to an inadequate residence time to oxidize the solid particles or trap them. The particles removal efficiencies of CRDPFs had high degree of correlations with the emission ratio of NO2/NOx. The PN emission results from two CRDPFs indicated that more NO2 generating in diesel oxidation catalyst section could obtain the higher removal efficiency of solid particles. However this also increased the risk of NO2 exposure in atmosphere.
基金financial support from the Natural Science Foundation of China (No. 21107096)the Zhejiang Provincial Natural Science Foundation of China (No. Y14E080035)the Commission of Science and Technology of Zhejiang province (No. 2013C03021)
文摘A series of Pt-V/Ce-Zr-O diesel oxidation catalysts was prepared using the impregnation method. The catalytic activity and sulfur resistance of Pt-V/Ce-Zr-O were investigated in the presence of simulated diesel exhaust. The effect of vanadium on the structure and redox properties of the catalysts was also investigated using the Brunauer-Emmett-Teller method,X-ray diffraction, H2temperature-programmed reduction, CO temperature-programmed desorption, X-ray photoelectron spectroscopy, and Energy Dispersive Spectroscopy. Results showed that the Pt particles were well dispersed on the Ce-Zr-O carrier through the vanadium isolation effect, which significantly improved the oxidation activity toward CO and hydrocarbons. An electron-withdrawing phenomenon occurred from V to Pt, resulting in an increase in the metallic nature of platinum, which was beneficial to hydrocarbon molecular activation.
基金supported by the Open Research Program of State Key Laboratory of Engine Combustion(No.K2018-11)the National Nature Science Foundation of China(No.51806015)the National Engineering Laboratory for Mobile Source Emission Control Technology(No.NELMS2018A17)
文摘Decomposition mass loss and pyrolysis products analyses of particles sampled at various locations along the tailpipe of a Euro-IV diesel engine were performed using a thermo gravimetry in conjunction with Fourier transformation infrared spectrometrymass spectrum.Diesel particles were collected at the same location with and without diesel oxidation catalyst(DOC)mounted on the test engine separately.The three poles in thermal gravity-differential thermal gravity images suggested that the decomposition process of diesel particles could be divided into three stages which correspond to the decompositions of lower boiling substances,higher boiling substances and soot respectively.It is noticed that no matter whether DOC was mounted or not,the further the particles were sampled away from the engine block,the lower the peak temperatures and the heavier the mass losses within the first two stages,which indicated that the soluble organic fraction in the particle samples increased and therefore lowering the activation energy of thermal decomposition.Hydroxyl,ammonia,C_xH_y fragments,benzene,toluene,and phenol were found to be the primary products of particle decomposition,which didn’t change with the location of particle sample point.The employment of DOC increased the activation energy for particle oxidation and resulted in a higher peak temperature and lower mass loss within the first-stage.Moreover,the C=O stretching bands of aldehyde and ketone at 1771 cm-1 was only detected without a DOC,while the N02 peak at 1634 cm-1 was solely noticed with the presence of DOC.Compared to the first-stage pyrolysis products,more polycyclic aromatic hydrocarbons and less C_xH_y fragments were seen in the second-stage.
基金Funded by the Foundation for Scientific Research Encouragement to Middle-aged and Young Scientists of Shandong Province (No. 2007BS04003)
文摘The V-K catalysts were produced on porous α-alumina substrate by a solution impregnation route and the compositions and catalytic activities for soot oxidation were studied by XRD, TG/DTG, DSC and TPR. According to the catalytic activity studies, the catalytic activity of the crystalline phases is in the order： KNO3＋KVO3〉K3V5O14＋KVO3. The appearance of excessive KHCO3 phase will lead to the deterioration of catalytic activity when the catalysts contain higher KNO3 content. It is also found that when the K∶V molar ratio is higher than 1∶1, the prepared catalysts show a strong CO2 absorption characteristic and this behavior will become gradually significant with the increasing of K∶V molar ratio. Considerable amount of absorbed CO2 are strongly bonded to the crystal lattice with onset desorption temperature of 200 ℃.
文摘Diesel soot is related to incomplete fuel oxidation, and possesses the well-known mutagenic effects on human health.Diesel soot was collected from diesel engines and oxidized in laboratorial micro reactor by several prepared rare earth-based catalysts with or without different harmful monoxide gases such as NO, and activities of several rare earth catalysts were studied.The results indicate that soot can be more easily oxidized with monoxide gases.
基金Project supported by National Key Research and Development Program of China(2018YFC1801706-01)the Natural Science Foundation of China(21663009,2216020078)the Science and Technology Project of Guizhou Province(20192835,2021480)。
文摘A series of Ce_(1-x)Ti_(x)O_(2)mixed oxide catalysts were synthesized by sol-gel method and then loading of noble metal(M=Pt,Rh,Ru)was used for soot oxidation.Ti-doped Ce_(1-x)Ti_(x)O_(2)catalysts(x is the molar ratio of Ti/(Ti+Ce)and ranges from 0.1 to 0.5)exhibit much better oxidation performance than CeO_(2)catalyst,and the Ce_(0.9)Ti_(0.1)O_(2)catalyst calcined at 500℃has the best catalysis activity.Each noble metal(1 wt%)was supported on Ce_(0.9)Ti_(0.1)O_(2)(M/C9 T1)and the properties of the catalysts were characterized by X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),Raman,Brunauer-Emmett-Teller(BET)method,and H_(2)-temperature programmed reduction(H_(2)-TPR)results.Results show that the introduction of Ti into CeO_(2)forming Ti-O-Ce structure enhances the catalytic activity and increases the number of oxygen vacancies at the catalyst surface.The noble metal is highly dispersed over Ce_(0.9)Ti_(0.1)O_(2),and M/C9 T1 catalysts present enhanced activity in comparison to Ce_(0.9)Ti_(0.1)O_(2).It is found that noble metals can greatly increase the activity of the catalyst and the corresponding oxidation rate of soot can enhance the electron transfer capacity and oxygen adsorption capacity of the catalyst.A small amount of Ti doping in CeO_(2)can significantly improve the activity of the catalyst,while a large amount of Ti reduces the performance of the catalyst because a large amount of Ti is enriched on the surface of the catalyst,which hinders the contact and reaction between the catalyst and the soot.
文摘An ultrasound-assisted heterogeneous catalytic oxidation process was applied to eliminate sulfur from commercial diesel fuel oil.The studied variables were catalyst concentration,type of catalyst(homogeneous or heterogeneous),oxidizing agent concentration,and the application of ultrasound energy.Supported catalysts were prepared by impregnation of coal fly ash with an iron(Ⅱ)sulfate aqueous solution using ultrasound energy.After drying,the catalyst was calcined at 500℃for 4 h.The oxidizing agent was hydrogen peroxide.Ultrasound energy was applied with a frequency of 47 kHz and an intensity of 147 W.Ethanol was employed for extracting the oxidized compounds from the hydrocarbon mixture.Coal fly ash and ethanol were used with the purpose of applying low-cost raw materials in chemical processes.It was found that under the studied conditions,increasing oxidizing agent concentration and the application of ultrasound energy can enhance the sulfur removal from commercial diesel fuel oil.Catalyst concentration did not play a significant role in the process.Similar results were obtained using homogeneous or heterogeneous catalyst,which is important since the heterogeneous catalyst could be recovered,reactivated,and used in many cycles.
文摘Diesel oxide catalysts and soot combustion catalysts were reported in this paper.The former was manufactured in mass last year, and enhanced performance is under development now.The later is screened out and further research is under way.The best soot combustion catalyst could ignite soot combustion even at 350 ℃, which is within the range of temperatures reached in diesel exhaust, and shows the catalytic combustion velocity nearly one time faster compared with non-catalytic combustion of soot, which is of benefit to rapid regeneration of diesel particulate filter, thus it might be an excellent practicable catalyst.
基金Sponsored by Postdoctoral Science Foundation of China(2007042031)
文摘In order to reduce oxides of nitrogen （NOx） emanated from a diesel engine, a comprehensive urea selective catalyst reduction （SCR） DeNOx catalyst was modeled in which numerical simulations were used as a complementary tool for the experimental investigations to make the design decisions, and hence shorten the de- velopment process. In this approach, relevant conversion reactions were studied in 1D model, and the parame- ters obtained in this way were transferred to 3D simulations. According to the results of the study, the conver- sion of NO and NO2 increased with the increase in monolith solid temperature. With the increase in the ratio of NO2/NOx the conversion of NO, NO2 and NOx increased resulting in maximum reduction of NOxat the ratio of 1; beyond this ratio, the conversion of NO2 and NOx decreased; however, NO continued to be converted till the ratio was 1.8. The conversion of NOx decreased with the increase in space velocity.
