The soot emitted during the operation of diesel engine exhaust seriously threatens the human health and environment,so treating diesel engine exhaust is critical.At present,the most effective method for eliminating so...The soot emitted during the operation of diesel engine exhaust seriously threatens the human health and environment,so treating diesel engine exhaust is critical.At present,the most effective method for eliminating soot particles is post-treatment technology.Preparation of economically viable and highly active soot combustion catalysts is a pivotal element of post-treatment technology.In this study,different single-metal oxide catalysts with fibrous structures and alkali metal-modified hollow nanotubular Mn-based oxide catalysts were synthesized using centrifugal spinning method.Activity evaluation results showed that the manganese oxide catalyst has the best catalytic activity among the prepared single-metal oxide catalysts.Further research on alkali metal modification showed that doping alkali metals is beneficial for improving the oxidation state of manganese and generating a large number of reactive oxygen species.Combined with the structural effect brought by the hollow nanotube structure,the alkali metal-modified Mn-based oxide catalysts exhibit superior catalytic performance.Among them,the Cs-modified Mn-based oxide catalyst exhibits the best catalytic performance because of its rich active oxygen species,excellent NO oxidation ability,abundant Mn^(4+)ions(M^(n4)+/Mn^(n+)=64.78%),and good redox ability.The T_(10),T_(50),T_(90),and CO_(2)selectivity of the Cs-modified Mn-based oxide catalyst were 267°C,324°C,360°C,and 97.8%,respectively.展开更多
Effective lattice oxygen(Olatt)activation at low temperatures has long been a challenge in catalytic oxidation reactions.Traditional thermal catalytic soot combustion,even with Pt/Pd catalysts,is inefficient at exhaus...Effective lattice oxygen(Olatt)activation at low temperatures has long been a challenge in catalytic oxidation reactions.Traditional thermal catalytic soot combustion,even with Pt/Pd catalysts,is inefficient at exhaust temperatures below 200℃,particularly under conditions of frequent idling.Herein,we report an effective strategy utilizing non-thermal plasma(NTP)to activate Olatt in Ce_(1–x)Co_(x)O_(2–δ)catalysts,achieving dramatic enhancement of the soot combustion rate at low temperatures.At 200℃ and 4.3 W(discharge power,P_(dis)),NTP-Ce_(0.8)Co_(0.2)O_(2–δ)achieved 96.9%soot conversion(X_(C)),99.0%CO_(2) selectivity(S(CO_(2)))and a maximum energy conversion efficiency(Emax)of 14.7 g kWh^(–1).Compared with previously reported results,NTP-Ce_(0.8)Co_(0.2)O_(2–δ)exhibits the highest S(CO_(2))and Emax values.Remarkably,even without heating,X_(C),Emax,and S(CO_(2))reached 92.1%,6.1 g kWh–1,and 97.5%,respectively,at 6.3 W(P_(dis)).The results of characterization and theoretical calculation demonstrated that Co dopes into the CeO_(2) crystal lattice and forms an asymmetric Ce–O–Co structure,making oxygen“easy come,easy go”,thereby enabling the rapid combustion of soot over NTP-Ce_(0.8)Co_(0.2)O_(2–δ).This study highlights the great potential of NTP for activating Olatt and provides valuable insights into the design of efficient NTP-adapted catalysts for oxidation reactions.展开更多
The disordered macroporous-mesoporous La_(1-x)Ce_(x)CoO_(3)catalysts were prepared by complexcombustion method with ethylene glycol as complexing agent at relatively low calcination temperature.The samples were charac...The disordered macroporous-mesoporous La_(1-x)Ce_(x)CoO_(3)catalysts were prepared by complexcombustion method with ethylene glycol as complexing agent at relatively low calcination temperature.The samples were characterized by means of X-ray diffraction,N_(2)adsorption-ndash;desorption,Xray photoelectron spectroscopy,transmission electron microscopy,hydrogen temperature-programmed reduction and soot temperature-programmed reduction,and so on.The results show that the use of complexing agent and relatively low calcination temperature increase the specific surface area of the catalyst and have abundant pore structure.The Ce ions introduced into lattice of LaCoO_(3)mainly exist in the form of tetravalent.At the same time,Ce ions enhance the redox performance of the catalyst and the mobility of active oxygen species,which enhances the catalytic activity of the catalyst for soot combustion.The results of activity test show that La0.9Ce0.1CoO3 catalyst exhibits the highest activity in the absence of NO and NO2,and its T10,T50 and T90 are 371,444,and 497℃,respectively.At the same time,a possible reaction mechanism is proposed in this study based on the turnover frequency(TOF)calculated by isothermal anaerobic titrations,XPS and XRD results.展开更多
Nowadays,air pollution has become a prominent environmental problem and has attracted much attention.With the increase of vehicle retention quantity,the exhaust emissions have become the main sources of air pollution....Nowadays,air pollution has become a prominent environmental problem and has attracted much attention.With the increase of vehicle retention quantity,the exhaust emissions have become the main sources of air pollution.To reduce pollution and hazards,vehicle exhaust emission regulations are becoming stricter and stricter,which puts forward higher requirements for purification of vehicle exhausts.At present,rare earths have been widely applied in vehicle exhaust purification because of their good catalytic performance,which is attributed to their unique 4 f electron layer structure occupied without full electrons,excellent oxygen storage/release capacity and redox ability.In this paper,the current status of rare earth catalysts and application of rare earth in different fuel vehicle exhaust catalysts,including three-way catalysts(TWCs)for gasoline vehicles,diesel exhaust catalysts for different pollutants(particulate matter(PM),NOx,CO and HC)and catalysts for new energy vehicles with different fuels,are summarized in detail.Meanwhile,the corresponding mechanisms and the role of rare earth in vehicle exhaust catalysts are also simultaneously described.Furthermore,the challenges and development directions of rare earth catalysts for the purification of vehicle exhausts are also proposed.展开更多
The performance of catalysts used in after-treatment systems is the key factor for the removal of diesel soot,which is an important component of atmosphericfine particle emissions.Herein,three-dimensionally ordered ma...The performance of catalysts used in after-treatment systems is the key factor for the removal of diesel soot,which is an important component of atmosphericfine particle emissions.Herein,three-dimensionally ordered macroporous–mesoporous Ti_(x)Si+(1-x)O_(2)(3DOM-m Ti_(x)Si+(1-x)O_(2))and its supported MnO_(x)catalysts doped with different alkali/alkaline-earth metals(AMnO_(x)/3 DOM-m Ti_(0.7)Si_(0.3)O_(2)(A:Li,Na,K,Ru,Cs,Mg,Ca,Sr,Ba))were prepared by mesoporous template(P123)-assisted colloidal crystal template(CCT)and incipient wetness impregnation methods,respectively.Physicochemical characterizations of the catalysts were performed using scanning electron microscopy,X-ray diffraction,N_(2)adsorption–desorption,H_(2)temperature-programmed reduction,O_(2)temperature-programmed desorption,NO temperature-programmed oxidation,and Raman spectroscopy techniques;then,we evaluated their catalytic performances for the removal of diesel soot particles.The results show that the 3DOM-m Ti_(0.7)Si_(0.3)O_(2)supports exhibited a well-defined 3DOM-m nanostructure,and AMnO_(x)nanoparticles with 10–50 nm were evenly dispersed on the inner walls of the uniform macropores.In addition,the as-prepared catalysts exhibited good catalytic performance for soot combustion.Among the prepared catalysts,CsMnO_(x)/3DOM-m Ti_(0.7)Si_(0.3)O_(2)had the highest catalytic activity for soot combustion,with T10,T50,and T90(the temperatures corresponding to soot conversion rates of 10%,50%,and 90%)values of 285,355,and 393℃,respectively.The high catalytic activity of the CsMnO_(x)/3 DOM-m Ti_(0.7)Si_(0.3)O_(2)catalysts was attributed to their excellent low-temperature reducibility and homogeneous macroporous–mesoporous structure,as well as to the synergistic effects between Cs and Mn species and between CsMnO_(x)and the Ti_(0.7)Si_(0.3)O_(2)support.展开更多
The elimination of pollutants from diesel exhaust has received widespread research attention as they cause serious air pollution and pose a threat to human health.Catalytic post-treatment technology is one of the most...The elimination of pollutants from diesel exhaust has received widespread research attention as they cause serious air pollution and pose a threat to human health.Catalytic post-treatment technology is one of the most effective and universal technologies to treat diesel exhaust pollutants.The design and development of efficient and low-cost catalysts is the key factor to realize the wide application of catalytic post-treatment technology.Cerium(Ce)-based oxides with specific morphologies are widely used to eliminate pollutants in diesel vehicle exhaust due to their unique physical and chemical properties,such as high catalytic activity,low cost and non-toxicity.In this review,the preparation methods of Cebased oxide materials with specific morphologies,such as nanoparticles,nanocubes,nanorods,nanofibers,and multi-stage pores,are introduced in detail,and the research progress on using these catalysts for the removal of carbon monoxide,hydrocarbons,soot particles,nitrogen oxides,and other pollutants from diesel exhaust is reviewed in detail.Finally,the unresolved issues associated with using Ce-based oxide catalysts with a specific morphology to catalytically remove pollutants from diesel exhaust are highlighted,and future application prospects and development directions are discussed.展开更多
A novel poly（ethyleneimine）/Au nanoparticles/hemin nanocomposite （PEI-AuNPs-Hemin） acting for Methyl Orange （MO） removal has been synthesized. PEI-AuNPs was prepared firstly and it was then linked to heroin thro...A novel poly（ethyleneimine）/Au nanoparticles/hemin nanocomposite （PEI-AuNPs-Hemin） acting for Methyl Orange （MO） removal has been synthesized. PEI-AuNPs was prepared firstly and it was then linked to heroin through the coupling between carboxyl groups in hemin and amino groups in PEI without the activation of carboxyl groups. The high reactivity and stability of AuNPs contributed greatly in the formation of the amido bonds in the nanocomposite. Fourier transform infrared spectroscopy, transmission electron microscopy and UV-visible spectroscopy were used to characterize the PEI-AuNPs-Hemin. Results show that PEI-AuNPs-Hemin has strong adsorption for MO. Adsorption and degradation experiments were carried out at different pHs, nanocomposite concentrations and UV irradiation times. Removal of MO in acidic solutions was more effective than in basic solutions. The real-time study showed that the MO degradation with the nanocom- posite under UV irradiation was a fast process. In addition, the photocatalytic degradation mechanism was proposed. The study suggests that the PEI-AuNPs-Hemin may have promising applications in environmental monitoring and protection.展开更多
The pursuit of high-performance is worth considerable effort in catalysis for energy efficiency and environmental sustainability. To develop redox catalysts with superior performance for soot combustion, a series of M...The pursuit of high-performance is worth considerable effort in catalysis for energy efficiency and environmental sustainability. To develop redox catalysts with superior performance for soot combustion, a series of Mn_(x)Co_(y) oxides were synthesized using MgO template substitution.This method greatly improves the preparation and catalytic efficiency and is more in line with the current theme of green catalysts and sustainable development. The resulting Mn_(1)Co_(2.3) has a strong activation capability of gaseous oxygen due to a high concentration of Co^(3+) and Mn^(3+). The Mn doping enhanced the intrinsic activity by prompting oxygen vacancy formation and gaseous oxygen adsorption. The nanosheet morphology with abundant mesoporous significantly increased the solid–solid contact efficiency and improved the adsorption capability of gaseous reactants. The novel design of Mn_(1)Co_(2.3)oxide enhanced its catalytic performance through a synergistic effect of Mn doping and the porous nanosheet morphology, showing significant potential for the preparation of high-performance soot combustion catalysts.展开更多
Diesel engine exhaust comprises nitrogen oxides(NOx)and soot particles,which cause serious air pollution.However,owing to the contradictory nature of NO_(x)reduction and soot oxidation,a trade-off exists in the simult...Diesel engine exhaust comprises nitrogen oxides(NOx)and soot particles,which cause serious air pollution.However,owing to the contradictory nature of NO_(x)reduction and soot oxidation,a trade-off exists in the simultaneous removal of NO_(x)and soot.Consequently,catalytic technology has become a hot research topic.This study prepared MOδ/Fe-Beta(M=Fe,Co,Ni,Mn,Cu)catalysts through incipient wetness impregnation using Fe-Beta as the support and explored the catalytic performance of the above catalysts.The results exhibited the good performance of the prepared catalysts.The introduction of Mn resulted in a lower peak temperature of soot combustion for the catalyst,and slightly decreased deNOx performance of Fe-Beta.The soot combustion temperature was as low as 422℃,and the temperature window for 80%NO conversion was 164-423℃.The interaction between MnOd and zeolite can regulate the acid sites and produce sufficient active oxygen species for the catalyst.The catalytic activity of the MnOδ/Fe-Beta catalyst is due to its strong redox property,the appropriate number of acid sites,and sufficient number of active oxygen species.In addition,the catalyst had good stability and water and sulfur resistance,therefore it had great potential for future application in the simultaneous removal of NO_(x)and soot from diesel engine exhaust.展开更多
Air pollution from particulate matter produced by incomplete combustion of diesel fuel has become a serious environmental pollution problem,which can be addressed by catalytic combustion.In this work,a series of K-mod...Air pollution from particulate matter produced by incomplete combustion of diesel fuel has become a serious environmental pollution problem,which can be addressed by catalytic combustion.In this work,a series of K-modified MnO_(δ)catalysts with different microstructures were synthesized by the hydrothermal method,the relationship between structure of the catalysts and their catalytic performance for soot combustion was studied by characterization techniques and density functional theory(DFT)calculations.Results showed that the prepared catalysts had good catalytic performance for soot combustion and could completely oxidize soot at temperatures below 400℃.The cryptomelane-type K_(2−x)Mn_(8)O_(16)(K-OMS-2)with tunnel structure had excellent NO oxidation capacity and abundance of Mn^(4+)ions(Mn^(4+)/Mn^(3+)=1.24)with good redox ability,it demonstrated better soot combustion performance than layered birnessite-type K_(2)Mn_(4)O_(8)(K-OL-1).The T_(10),T_(50),T_(90)temperatures of KOMS-2 were 269,314,346℃,respectively.The K-OMS-2 catalyst also showed excellent stability after five catalytic cycles,with T_(10),T_(50),T_(90)values holding in the ranges of 270±2,316±2,348±3℃,respectively.展开更多
基金supported by National Key R&D Program of China(2022YFB3506200,2022YFB3504100)National Natural Science Foundation of China(22072095,22372107,22202058)+3 种基金Excellent Youth Science Foundation of Liaoning Province(2022-YQ-20)Shenyang Science and Technology Planning Project(22-322-3-28)Liaoning Xingliao talented youth Top talent program(XLYC2203007)University Joint Education Project for China-Central and Eastern European Countries(2021097).
文摘The soot emitted during the operation of diesel engine exhaust seriously threatens the human health and environment,so treating diesel engine exhaust is critical.At present,the most effective method for eliminating soot particles is post-treatment technology.Preparation of economically viable and highly active soot combustion catalysts is a pivotal element of post-treatment technology.In this study,different single-metal oxide catalysts with fibrous structures and alkali metal-modified hollow nanotubular Mn-based oxide catalysts were synthesized using centrifugal spinning method.Activity evaluation results showed that the manganese oxide catalyst has the best catalytic activity among the prepared single-metal oxide catalysts.Further research on alkali metal modification showed that doping alkali metals is beneficial for improving the oxidation state of manganese and generating a large number of reactive oxygen species.Combined with the structural effect brought by the hollow nanotube structure,the alkali metal-modified Mn-based oxide catalysts exhibit superior catalytic performance.Among them,the Cs-modified Mn-based oxide catalyst exhibits the best catalytic performance because of its rich active oxygen species,excellent NO oxidation ability,abundant Mn^(4+)ions(M^(n4)+/Mn^(n+)=64.78%),and good redox ability.The T_(10),T_(50),T_(90),and CO_(2)selectivity of the Cs-modified Mn-based oxide catalyst were 267°C,324°C,360°C,and 97.8%,respectively.
文摘Effective lattice oxygen(Olatt)activation at low temperatures has long been a challenge in catalytic oxidation reactions.Traditional thermal catalytic soot combustion,even with Pt/Pd catalysts,is inefficient at exhaust temperatures below 200℃,particularly under conditions of frequent idling.Herein,we report an effective strategy utilizing non-thermal plasma(NTP)to activate Olatt in Ce_(1–x)Co_(x)O_(2–δ)catalysts,achieving dramatic enhancement of the soot combustion rate at low temperatures.At 200℃ and 4.3 W(discharge power,P_(dis)),NTP-Ce_(0.8)Co_(0.2)O_(2–δ)achieved 96.9%soot conversion(X_(C)),99.0%CO_(2) selectivity(S(CO_(2)))and a maximum energy conversion efficiency(Emax)of 14.7 g kWh^(–1).Compared with previously reported results,NTP-Ce_(0.8)Co_(0.2)O_(2–δ)exhibits the highest S(CO_(2))and Emax values.Remarkably,even without heating,X_(C),Emax,and S(CO_(2))reached 92.1%,6.1 g kWh–1,and 97.5%,respectively,at 6.3 W(P_(dis)).The results of characterization and theoretical calculation demonstrated that Co dopes into the CeO_(2) crystal lattice and forms an asymmetric Ce–O–Co structure,making oxygen“easy come,easy go”,thereby enabling the rapid combustion of soot over NTP-Ce_(0.8)Co_(0.2)O_(2–δ).This study highlights the great potential of NTP for activating Olatt and provides valuable insights into the design of efficient NTP-adapted catalysts for oxidation reactions.
基金National Natural Science Foundation of China(21761162016)Key R&D Planning Research Project of Liaoning Province(2107229008)Science and Technology Research Planning Project of Shenyang City(Z17-5-056)。
文摘The disordered macroporous-mesoporous La_(1-x)Ce_(x)CoO_(3)catalysts were prepared by complexcombustion method with ethylene glycol as complexing agent at relatively low calcination temperature.The samples were characterized by means of X-ray diffraction,N_(2)adsorption-ndash;desorption,Xray photoelectron spectroscopy,transmission electron microscopy,hydrogen temperature-programmed reduction and soot temperature-programmed reduction,and so on.The results show that the use of complexing agent and relatively low calcination temperature increase the specific surface area of the catalyst and have abundant pore structure.The Ce ions introduced into lattice of LaCoO_(3)mainly exist in the form of tetravalent.At the same time,Ce ions enhance the redox performance of the catalyst and the mobility of active oxygen species,which enhances the catalytic activity of the catalyst for soot combustion.The results of activity test show that La0.9Ce0.1CoO3 catalyst exhibits the highest activity in the absence of NO and NO2,and its T10,T50 and T90 are 371,444,and 497℃,respectively.At the same time,a possible reaction mechanism is proposed in this study based on the turnover frequency(TOF)calculated by isothermal anaerobic titrations,XPS and XRD results.
基金supported by the National Natural Science Foundation of China(U1908204,22072095,21761162016)Key Research and Development Program of MOST(2017YFE0131200)+2 种基金General Projects of Liaoning Province Natural Fund(2019-MS-284)National Engineering Laboratory for Mobile Source Emission Control Technology(NELMS2018A04)University Level Innovation Team of Shenyang Normal University and Major Incubation Program of Shenyang Normal University(ZD201901)。
文摘Nowadays,air pollution has become a prominent environmental problem and has attracted much attention.With the increase of vehicle retention quantity,the exhaust emissions have become the main sources of air pollution.To reduce pollution and hazards,vehicle exhaust emission regulations are becoming stricter and stricter,which puts forward higher requirements for purification of vehicle exhausts.At present,rare earths have been widely applied in vehicle exhaust purification because of their good catalytic performance,which is attributed to their unique 4 f electron layer structure occupied without full electrons,excellent oxygen storage/release capacity and redox ability.In this paper,the current status of rare earth catalysts and application of rare earth in different fuel vehicle exhaust catalysts,including three-way catalysts(TWCs)for gasoline vehicles,diesel exhaust catalysts for different pollutants(particulate matter(PM),NOx,CO and HC)and catalysts for new energy vehicles with different fuels,are summarized in detail.Meanwhile,the corresponding mechanisms and the role of rare earth in vehicle exhaust catalysts are also simultaneously described.Furthermore,the challenges and development directions of rare earth catalysts for the purification of vehicle exhausts are also proposed.
基金supported by Key Research and Development Program of Ministry of Science and Technology of the People’s Republic of China(MOST)(No.2017YFE0131200)for collaboration between China and PolandNational Nature Science Foundation of China(NSFC)(Nos.22072095,U1908204,21761162016)+3 种基金General Projects of Liaoning Province Natural Fund(No.2019-MS-284)National Engineering Laboratory for Mobile Source Emission Control Technology(No.NELMS2018A04)University level innovation team of Shenyang Normal University,Major Incubation Program of Shenyang Normal University(No.ZD201901)supported by the Research Grants Council(RGC)of Hong Kong through NSFC/RGC Joint Research Scheme(No.N_CUHK451/17)。
文摘The performance of catalysts used in after-treatment systems is the key factor for the removal of diesel soot,which is an important component of atmosphericfine particle emissions.Herein,three-dimensionally ordered macroporous–mesoporous Ti_(x)Si+(1-x)O_(2)(3DOM-m Ti_(x)Si+(1-x)O_(2))and its supported MnO_(x)catalysts doped with different alkali/alkaline-earth metals(AMnO_(x)/3 DOM-m Ti_(0.7)Si_(0.3)O_(2)(A:Li,Na,K,Ru,Cs,Mg,Ca,Sr,Ba))were prepared by mesoporous template(P123)-assisted colloidal crystal template(CCT)and incipient wetness impregnation methods,respectively.Physicochemical characterizations of the catalysts were performed using scanning electron microscopy,X-ray diffraction,N_(2)adsorption–desorption,H_(2)temperature-programmed reduction,O_(2)temperature-programmed desorption,NO temperature-programmed oxidation,and Raman spectroscopy techniques;then,we evaluated their catalytic performances for the removal of diesel soot particles.The results show that the 3DOM-m Ti_(0.7)Si_(0.3)O_(2)supports exhibited a well-defined 3DOM-m nanostructure,and AMnO_(x)nanoparticles with 10–50 nm were evenly dispersed on the inner walls of the uniform macropores.In addition,the as-prepared catalysts exhibited good catalytic performance for soot combustion.Among the prepared catalysts,CsMnO_(x)/3DOM-m Ti_(0.7)Si_(0.3)O_(2)had the highest catalytic activity for soot combustion,with T10,T50,and T90(the temperatures corresponding to soot conversion rates of 10%,50%,and 90%)values of 285,355,and 393℃,respectively.The high catalytic activity of the CsMnO_(x)/3 DOM-m Ti_(0.7)Si_(0.3)O_(2)catalysts was attributed to their excellent low-temperature reducibility and homogeneous macroporous–mesoporous structure,as well as to the synergistic effects between Cs and Mn species and between CsMnO_(x)and the Ti_(0.7)Si_(0.3)O_(2)support.
基金Project supported by National Key R&D Program of China(2022YFB3506200,2022YFB3504100)National Natural Science Foundation of China(22372107,22072095,U1908204)+2 种基金Excellent Youth Science Foundation of Liaoning Province(2022-YQ-20)Shenyang Science and Technology Planning Project(22-322-3-28)University Joint Education Project for China-Central and Eastern European Countries(2021097)。
文摘The elimination of pollutants from diesel exhaust has received widespread research attention as they cause serious air pollution and pose a threat to human health.Catalytic post-treatment technology is one of the most effective and universal technologies to treat diesel exhaust pollutants.The design and development of efficient and low-cost catalysts is the key factor to realize the wide application of catalytic post-treatment technology.Cerium(Ce)-based oxides with specific morphologies are widely used to eliminate pollutants in diesel vehicle exhaust due to their unique physical and chemical properties,such as high catalytic activity,low cost and non-toxicity.In this review,the preparation methods of Cebased oxide materials with specific morphologies,such as nanoparticles,nanocubes,nanorods,nanofibers,and multi-stage pores,are introduced in detail,and the research progress on using these catalysts for the removal of carbon monoxide,hydrocarbons,soot particles,nitrogen oxides,and other pollutants from diesel exhaust is reviewed in detail.Finally,the unresolved issues associated with using Ce-based oxide catalysts with a specific morphology to catalytically remove pollutants from diesel exhaust are highlighted,and future application prospects and development directions are discussed.
基金supported by the National Natural Science Foundation of China(No.21575066)the Technology Foundation for Selected Overseas Scholar in Nanjing
文摘A novel poly（ethyleneimine）/Au nanoparticles/hemin nanocomposite （PEI-AuNPs-Hemin） acting for Methyl Orange （MO） removal has been synthesized. PEI-AuNPs was prepared firstly and it was then linked to heroin through the coupling between carboxyl groups in hemin and amino groups in PEI without the activation of carboxyl groups. The high reactivity and stability of AuNPs contributed greatly in the formation of the amido bonds in the nanocomposite. Fourier transform infrared spectroscopy, transmission electron microscopy and UV-visible spectroscopy were used to characterize the PEI-AuNPs-Hemin. Results show that PEI-AuNPs-Hemin has strong adsorption for MO. Adsorption and degradation experiments were carried out at different pHs, nanocomposite concentrations and UV irradiation times. Removal of MO in acidic solutions was more effective than in basic solutions. The real-time study showed that the MO degradation with the nanocom- posite under UV irradiation was a fast process. In addition, the photocatalytic degradation mechanism was proposed. The study suggests that the PEI-AuNPs-Hemin may have promising applications in environmental monitoring and protection.
基金supported by the top talent program of Henan Agricultural University[grant numbers 30501029].
文摘The pursuit of high-performance is worth considerable effort in catalysis for energy efficiency and environmental sustainability. To develop redox catalysts with superior performance for soot combustion, a series of Mn_(x)Co_(y) oxides were synthesized using MgO template substitution.This method greatly improves the preparation and catalytic efficiency and is more in line with the current theme of green catalysts and sustainable development. The resulting Mn_(1)Co_(2.3) has a strong activation capability of gaseous oxygen due to a high concentration of Co^(3+) and Mn^(3+). The Mn doping enhanced the intrinsic activity by prompting oxygen vacancy formation and gaseous oxygen adsorption. The nanosheet morphology with abundant mesoporous significantly increased the solid–solid contact efficiency and improved the adsorption capability of gaseous reactants. The novel design of Mn_(1)Co_(2.3)oxide enhanced its catalytic performance through a synergistic effect of Mn doping and the porous nanosheet morphology, showing significant potential for the preparation of high-performance soot combustion catalysts.
基金supported by National Natural Science Foundation of China(22372107,22072095,22202058)Postgraduate Education Reform Project of Liaoning Province(LNYJG2022400,LNYJG2023280)+3 种基金National Key Research and Development Program of China(2022YFB3506200,2022YFB3504100)Excellent Youth Science Foundation of Liaoning Province(2022-YQ-20)Shenyang Science and Technology Planning Project(22-322-3-28)Liaoning Xingliao talented youth Top talent program(XLYC2203007).
文摘Diesel engine exhaust comprises nitrogen oxides(NOx)and soot particles,which cause serious air pollution.However,owing to the contradictory nature of NO_(x)reduction and soot oxidation,a trade-off exists in the simultaneous removal of NO_(x)and soot.Consequently,catalytic technology has become a hot research topic.This study prepared MOδ/Fe-Beta(M=Fe,Co,Ni,Mn,Cu)catalysts through incipient wetness impregnation using Fe-Beta as the support and explored the catalytic performance of the above catalysts.The results exhibited the good performance of the prepared catalysts.The introduction of Mn resulted in a lower peak temperature of soot combustion for the catalyst,and slightly decreased deNOx performance of Fe-Beta.The soot combustion temperature was as low as 422℃,and the temperature window for 80%NO conversion was 164-423℃.The interaction between MnOd and zeolite can regulate the acid sites and produce sufficient active oxygen species for the catalyst.The catalytic activity of the MnOδ/Fe-Beta catalyst is due to its strong redox property,the appropriate number of acid sites,and sufficient number of active oxygen species.In addition,the catalyst had good stability and water and sulfur resistance,therefore it had great potential for future application in the simultaneous removal of NO_(x)and soot from diesel engine exhaust.
基金the Key Research and Development Program of MOST(No.2017YFE0131200)for collaboration between China and Polandthe National Natural Science Foundation of China(Nos.22072095 and U1908204)+5 种基金University Joint Education Project for China-Central and Eastern European Countries(No.2021097)National Engineering Laboratory for Mobile Source Emission Control Technology(No.NELMS2018A04)Liaoning Provincial central government guides local science and technology development funds(No.2022JH6/100100052)Major/Key Project of Graduate Education and Teaching Reform of Shenyang Normal University(No.YJSJG120210008/YJSJG220210022)University level innovation team of Shenyang Normal Universityand Major Incubation Program of Shenyang Normal University(No.ZD201901)。
文摘Air pollution from particulate matter produced by incomplete combustion of diesel fuel has become a serious environmental pollution problem,which can be addressed by catalytic combustion.In this work,a series of K-modified MnO_(δ)catalysts with different microstructures were synthesized by the hydrothermal method,the relationship between structure of the catalysts and their catalytic performance for soot combustion was studied by characterization techniques and density functional theory(DFT)calculations.Results showed that the prepared catalysts had good catalytic performance for soot combustion and could completely oxidize soot at temperatures below 400℃.The cryptomelane-type K_(2−x)Mn_(8)O_(16)(K-OMS-2)with tunnel structure had excellent NO oxidation capacity and abundance of Mn^(4+)ions(Mn^(4+)/Mn^(3+)=1.24)with good redox ability,it demonstrated better soot combustion performance than layered birnessite-type K_(2)Mn_(4)O_(8)(K-OL-1).The T_(10),T_(50),T_(90)temperatures of KOMS-2 were 269,314,346℃,respectively.The K-OMS-2 catalyst also showed excellent stability after five catalytic cycles,with T_(10),T_(50),T_(90)values holding in the ranges of 270±2,316±2,348±3℃,respectively.
