The ultrafine Ce-based oxide nanoparticles with different element dopings （Zr, Y） were synthesized by the method of mi- cropores-diffused coprecipitation （MDC） using ammonia solution as the precipitation agent. Th...The ultrafine Ce-based oxide nanoparticles with different element dopings （Zr, Y） were synthesized by the method of mi- cropores-diffused coprecipitation （MDC） using ammonia solution as the precipitation agent. The activities of the catalysts for soot oxidation were evaluated by the temperature-programmed oxidation （TPO） reaction. Ce-based oxides prepared in this study exhibited high catalytic activity for soot oxidation under tile condition of loose contact between soot particles and catalysts, and the catalytic ac- tivity ofultrafine Ce0.gZr0 iO2 nanoparticle for soot combustion was the highest, whose/＂10, Ts0 and Sco2m was 364, 442 ~C and 98.3%, respectively. All catalysts were systematically characterized by means of X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, Brumauer-Emett-Teller （BET）, Fourier transform infrared spectroscopy （FT-IR） and UV-Vis diffuse reflectance spectroscopy （UV-Vis DRS）. It was indicated that the MDC method could prepare the ultrafine Ce-bascd oxide nanoparticles whose the crystal lattice were perfect, and the BET surface area and average crystal size of the ultrafine nanoparticles changed with the different element dopings （Zr, Y）. The H2-TPR measurements showed that the ultrafine Ce-based ox- ide nanoparticles with the doping-Zr cation could be favorable for improving the redox property of the catalysts.展开更多
Refractory organic pollutants in water threaten human health and environmental safety,and advanced oxidation processes (AOPs) are effective for the degradation of these pollutants.Catalysts play vital role in AOPs,and...Refractory organic pollutants in water threaten human health and environmental safety,and advanced oxidation processes (AOPs) are effective for the degradation of these pollutants.Catalysts play vital role in AOPs,and Ce-based catalysts have exhibited excellent performance.Recently,the development and application of Ce-based catalysts in various AOPs have been reported.Our study conducts the first review in this rapid growing field.This paper clarifies the variety and properties of Ce-based catalysts.Their applications in different AOP systems (catalytic ozonation,photodegradation,Fenton-like reactions,sulfate radicalbased AOPs,and catalytic sonochemistry) are discussed.Different Ce-based catalysts suit different reaction systems and produce different active radicals.Finally,future research directions of Ce-based catalysts in AOP systems are suggested.展开更多
The neuroinflammatory responses following ischemic stroke cause irreversible nerve cell death.Cell free-double strand DNA(dsDNA)segments from ischemic tissue debris are engulfed by microglia and sensed by their cyclic...The neuroinflammatory responses following ischemic stroke cause irreversible nerve cell death.Cell free-double strand DNA(dsDNA)segments from ischemic tissue debris are engulfed by microglia and sensed by their cyclic GMP-AMP synthase(cGAS),which triggers robust activation of the innate immune stimulator of interferon genes(STING)pathway and initiate the chronic inflammatory cascade.The decomposition of immunogenic dsDNA and inhibition of the innate immune STING are synergistic immunologic targets for ameliorating neuroinflammation.To combine the anti-inflammatory strategies of STING inhibition and dsDNA elimination,we constructed a DNase-mimetic artificial enzyme loaded with C-176.Nanoparticles are self-assembled by amphiphilic copolymers(P[CL35-b-(OEGMA20.7-co-NTAMA14.3)]),C-176,and Ce^(4+)which is coordinated with nitrilotriacetic acid(NTA)group to form corresponding catalytic structures.Our work developed a new nano-drug that balances the cGAS-STING axis to enhance the therapeutic impact of stroke by combining the DNase-memetic Ce^(4+)enzyme and STING inhibitor synergistically.In conclusion,it is a novel approach to modulating central nervus system(CNS)inflammatory signaling pathways and improving stroke prognosis.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
The localization and incomplete filling of 4f electrons endow cerium(Ce)with the great potential in electrocatalysis and photocatalysis.The unique 5d empty orbital of Ce elements can be used as a hydrogen“trap”site,...The localization and incomplete filling of 4f electrons endow cerium(Ce)with the great potential in electrocatalysis and photocatalysis.The unique 5d empty orbital of Ce elements can be used as a hydrogen“trap”site,which is conducive to the recombination of hydrogen ions or atoms and effectively promotes the desorption of hydrogen molecules in electrocatalysis.Meanwhile,due to the stable crystal structure,excellent oxygen mobility,and good optical properties,Ce-based nanomaterials are considered as one of the most desirable photocatalytic catalysts and widely used in atmospheric conditions.Therefore,cerium-based nanomaterials have considerable application prospects in photocatalysis and electrocatalysis.In this review,we summarize the preparation methods of Ce-based nanomaterials,and discuss the application of Ce-based nanomaterials in electrocatalysis and photocatalysis.Among them,electrocatalysis applications include the following:oxygen reduction reaction(ORR),hydrogen evolution reaction(HER),oxygen evolution reaction(OER),CO_(2) reduction reaction(CO_(2)RR),and other electrocatalysis,and photocatalysis applications include HER,CO_(2)RR,photodegradation,and other photocatalysis.Through the summary of present progress in the application of Ce-based nanomaterials in electrocatalytic and photocatalytic reaction,this review provides a reasonable prospect on the Ce-based nanomaterials in electrocatalysis and photocatalysis.展开更多
The challenges posed by energy and environmental issues have forced mankind to explore and utilize unconventional energy sources.It is imperative to convert the abundant coalbed gas(CBG)into high value-added products,...The challenges posed by energy and environmental issues have forced mankind to explore and utilize unconventional energy sources.It is imperative to convert the abundant coalbed gas(CBG)into high value-added products,i.e.,selective and efficient conversion of methane from CBG.Methane activation,known as the“holy grail”,poses a challenge to the design and development of catalysts.The structural complexity of the active metal on the carrier is of particular concern.In this work,we have studied the nucleation growth of small Co clusters(up to Co_(6))on the surface of CeO_(2)(110)using density functional theory,from which a stable loaded Co/CeO_(2)(110)structure was selected to investigate the methane activation mechanism.Despite the relatively small size of the selected Co clusters,the obtained Co_(x)/CeO_(2)(110)exhibits interesting properties.The optimized Co_(5)/CeO_(2)(110)structure was selected as the optimal structure to study the activation mechanism of methane due to its competitive electronic structure,adsorption energy and binding energy.The energy barriers for the stepwise dissociation of methane to form CH3^(*),CH2^(*),CH^(*),and C^(*)radical fragments are 0.44,0.55,0.31,and 1.20 eV,respectively,indicating that CH^(*)dissociative dehydrogenation is the rate-determining step for the system under investigation here.This fundamental study of metal-support interactions based on Co growth on the CeO_(2)(110)surface contributes to the understanding of the essence of Co/CeO_(2) catalysts with promising catalytic behavior.It provides theoretical guidance for better designing the optimal Co/CeO_(2) catalyst for tailored catalytic reactions.展开更多
Ce-based magnets have attracted extensive attention in both academia and industry due to their excellent property-price ratio and distinctive phase structures.Characteristically,Ce-based sintered magnets have widely t...Ce-based magnets have attracted extensive attention in both academia and industry due to their excellent property-price ratio and distinctive phase structures.Characteristically,Ce-based sintered magnets have widely tunable magnetic properties with changing Ce contents.Therefore,they can be used to meet many different application requirements from packaging market to driving motors,etc.The intrinsic magnetic properties,phase composition,and microstructures of the Ce-based sintered magnets with different Ce contents have been summarized.The service performances such as temperature stability,corrosion resistance,mechanical properties and thermal expansion of commercial Ce-based sintered magnets are introduced.The research and development trends of the Ce-based magnets in the future are pointed out.展开更多
Non-noble metal catalysts are suitable for the oxygen evolution reaction(OER)owing to their original oxidation states and oxygen coordination environments,which can regulate the adsorption of OH−at the active sites to...Non-noble metal catalysts are suitable for the oxygen evolution reaction(OER)owing to their original oxidation states and oxygen coordination environments,which can regulate the adsorption of OH−at the active sites to facilitate the formation of oxygencontaining intermediates.However,the difficulties encountered in the conversion of intermediates(M–OH,M–O,and M–OOH)lead to low efficiency.Decorations of transition metal catalysts with foreign elements are regarded effective solutions,among which decoration with Ce-based materials(CeBM)is the most prominent.This review investigates the current status and future prospects of CeBM-decorated transition metal electrocatalysts.By presenting a thorough account of the latest development,we aim to set a common ground for the research community for a deeper understanding of the roles of CeBM that originate from its unique electronic structure and abundant oxygen vacancies.Moreover,we wish to provide our own perspectives as to how to further the design of Ce-based OER electrocatalysts and where such catalysts may be applied in fields beyond electrocatalysis.展开更多
The isothermal crystallization behaviors in a newly developed CeGaCu bulk metallic glass have been investigated through the classic differential scanning calorimeter （DSC） method. It is found that the apparent activ...The isothermal crystallization behaviors in a newly developed CeGaCu bulk metallic glass have been investigated through the classic differential scanning calorimeter （DSC） method. It is found that the apparent activation energy （Ea） strongly depends on the fraction （x） of isothermal crystallization. Johnson-Mehl-Avrami （JMA） formula was used to analyze the mechanism of crystallization and the obtained Avrami exponent （n） was discovered to show an obvious correlation with the crystallization fraction x. With the help of the relation between Ea and n, the nucleation and growth activation energies, En and Eg, were estimated to be 214-304 kJ/mol and 91 kJ/mol, respectively. This result suggests that the main energy barrier against crystallization in the present glass should be the nucleation of nucleates, rather than the growth of crystals. Such a large E, is also believed to be responsible for the good glass forming ability of the CeGaCu alloy.展开更多
我们采用柠檬酸配合法制备了Ce基复合氧化物催化剂,分别在热重分析仪(TG)和管式反应器中测试了其氧化碳烟及同时脱除NOx的催化活性;并利用XRD、BET、H2-TPR、XPS表征手段考察其结构.其中,Co0.1/C e La0.05复合氧化物同时催化去除碳烟和...我们采用柠檬酸配合法制备了Ce基复合氧化物催化剂,分别在热重分析仪(TG)和管式反应器中测试了其氧化碳烟及同时脱除NOx的催化活性;并利用XRD、BET、H2-TPR、XPS表征手段考察其结构.其中,Co0.1/C e La0.05复合氧化物同时催化去除碳烟和NOx的性能最佳,碳烟脱除率为50%的反应温度为301℃,N2产率为41.4%.实验结果表明,Co主要以氧化物形式均匀分散在Ce-La固溶体表面,Co3+与Co2+价态共存,离子间的变价有利于提高催化剂的氧化还原性能,有效降低了碳烟的起燃温度.La的引入增大了催化剂的比表面积,抑制了Ce O2晶粒长大,进而提高了N2产率.部分La和Co形成了微量的La Co O3,形成了更多氧空位,有利于提高催化氧化碳烟的活性.展开更多
基金supported by National Natural Science Foundation of China(21177160,21173270 and 21303263)
文摘The ultrafine Ce-based oxide nanoparticles with different element dopings （Zr, Y） were synthesized by the method of mi- cropores-diffused coprecipitation （MDC） using ammonia solution as the precipitation agent. The activities of the catalysts for soot oxidation were evaluated by the temperature-programmed oxidation （TPO） reaction. Ce-based oxides prepared in this study exhibited high catalytic activity for soot oxidation under tile condition of loose contact between soot particles and catalysts, and the catalytic ac- tivity ofultrafine Ce0.gZr0 iO2 nanoparticle for soot combustion was the highest, whose/＂10, Ts0 and Sco2m was 364, 442 ~C and 98.3%, respectively. All catalysts were systematically characterized by means of X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, Brumauer-Emett-Teller （BET）, Fourier transform infrared spectroscopy （FT-IR） and UV-Vis diffuse reflectance spectroscopy （UV-Vis DRS）. It was indicated that the MDC method could prepare the ultrafine Ce-bascd oxide nanoparticles whose the crystal lattice were perfect, and the BET surface area and average crystal size of the ultrafine nanoparticles changed with the different element dopings （Zr, Y）. The H2-TPR measurements showed that the ultrafine Ce-based ox- ide nanoparticles with the doping-Zr cation could be favorable for improving the redox property of the catalysts.
基金supported by National Water Pollution Control and Treatment Science and Technology Major Project (No.2018ZX07110003)the National Natural Science Foundation of China (No.51779068)。
文摘Refractory organic pollutants in water threaten human health and environmental safety,and advanced oxidation processes (AOPs) are effective for the degradation of these pollutants.Catalysts play vital role in AOPs,and Ce-based catalysts have exhibited excellent performance.Recently,the development and application of Ce-based catalysts in various AOPs have been reported.Our study conducts the first review in this rapid growing field.This paper clarifies the variety and properties of Ce-based catalysts.Their applications in different AOP systems (catalytic ozonation,photodegradation,Fenton-like reactions,sulfate radicalbased AOPs,and catalytic sonochemistry) are discussed.Different Ce-based catalysts suit different reaction systems and produce different active radicals.Finally,future research directions of Ce-based catalysts in AOP systems are suggested.
基金the National Natural Science Foundation of China(No.22161132027,82272465,and 52273152)Zhejiang Provincial Natural Science Foundation of China(LY20H060008)+2 种基金the Starry Night Science Fund of Zhejiang University Shanghai Institute for Advanced Study(SN-ZJU-SIAS-006)‘Open Competition to Select the Best Candidates’Key Technology Program for Nucleic Acid Drugs of NCTIB(Grant No.NCTIB2022HS02006)Zhejiang High-Level Young Talent Special Support Plan for Dr.Zhengwei Mao.
文摘The neuroinflammatory responses following ischemic stroke cause irreversible nerve cell death.Cell free-double strand DNA(dsDNA)segments from ischemic tissue debris are engulfed by microglia and sensed by their cyclic GMP-AMP synthase(cGAS),which triggers robust activation of the innate immune stimulator of interferon genes(STING)pathway and initiate the chronic inflammatory cascade.The decomposition of immunogenic dsDNA and inhibition of the innate immune STING are synergistic immunologic targets for ameliorating neuroinflammation.To combine the anti-inflammatory strategies of STING inhibition and dsDNA elimination,we constructed a DNase-mimetic artificial enzyme loaded with C-176.Nanoparticles are self-assembled by amphiphilic copolymers(P[CL35-b-(OEGMA20.7-co-NTAMA14.3)]),C-176,and Ce^(4+)which is coordinated with nitrilotriacetic acid(NTA)group to form corresponding catalytic structures.Our work developed a new nano-drug that balances the cGAS-STING axis to enhance the therapeutic impact of stroke by combining the DNase-memetic Ce^(4+)enzyme and STING inhibitor synergistically.In conclusion,it is a novel approach to modulating central nervus system(CNS)inflammatory signaling pathways and improving stroke prognosis.
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 Key Research and Development Program of China(2022YFB3506200)the National Natural Science Foundation of China(22122113)。
文摘The localization and incomplete filling of 4f electrons endow cerium(Ce)with the great potential in electrocatalysis and photocatalysis.The unique 5d empty orbital of Ce elements can be used as a hydrogen“trap”site,which is conducive to the recombination of hydrogen ions or atoms and effectively promotes the desorption of hydrogen molecules in electrocatalysis.Meanwhile,due to the stable crystal structure,excellent oxygen mobility,and good optical properties,Ce-based nanomaterials are considered as one of the most desirable photocatalytic catalysts and widely used in atmospheric conditions.Therefore,cerium-based nanomaterials have considerable application prospects in photocatalysis and electrocatalysis.In this review,we summarize the preparation methods of Ce-based nanomaterials,and discuss the application of Ce-based nanomaterials in electrocatalysis and photocatalysis.Among them,electrocatalysis applications include the following:oxygen reduction reaction(ORR),hydrogen evolution reaction(HER),oxygen evolution reaction(OER),CO_(2) reduction reaction(CO_(2)RR),and other electrocatalysis,and photocatalysis applications include HER,CO_(2)RR,photodegradation,and other photocatalysis.Through the summary of present progress in the application of Ce-based nanomaterials in electrocatalytic and photocatalytic reaction,this review provides a reasonable prospect on the Ce-based nanomaterials in electrocatalysis and photocatalysis.
基金National Natural Science Foundation of China(52174279)Analysis and Testing Foundation of Kunming University of Science and Technology(2022M20202202138)Yunnan Fundamental Research Projects(202301AU070027).
文摘The challenges posed by energy and environmental issues have forced mankind to explore and utilize unconventional energy sources.It is imperative to convert the abundant coalbed gas(CBG)into high value-added products,i.e.,selective and efficient conversion of methane from CBG.Methane activation,known as the“holy grail”,poses a challenge to the design and development of catalysts.The structural complexity of the active metal on the carrier is of particular concern.In this work,we have studied the nucleation growth of small Co clusters(up to Co_(6))on the surface of CeO_(2)(110)using density functional theory,from which a stable loaded Co/CeO_(2)(110)structure was selected to investigate the methane activation mechanism.Despite the relatively small size of the selected Co clusters,the obtained Co_(x)/CeO_(2)(110)exhibits interesting properties.The optimized Co_(5)/CeO_(2)(110)structure was selected as the optimal structure to study the activation mechanism of methane due to its competitive electronic structure,adsorption energy and binding energy.The energy barriers for the stepwise dissociation of methane to form CH3^(*),CH2^(*),CH^(*),and C^(*)radical fragments are 0.44,0.55,0.31,and 1.20 eV,respectively,indicating that CH^(*)dissociative dehydrogenation is the rate-determining step for the system under investigation here.This fundamental study of metal-support interactions based on Co growth on the CeO_(2)(110)surface contributes to the understanding of the essence of Co/CeO_(2) catalysts with promising catalytic behavior.It provides theoretical guidance for better designing the optimal Co/CeO_(2) catalyst for tailored catalytic reactions.
基金This work was financially supported by the National Natural Science Foundation of China(51590882,51331003).
文摘Ce-based magnets have attracted extensive attention in both academia and industry due to their excellent property-price ratio and distinctive phase structures.Characteristically,Ce-based sintered magnets have widely tunable magnetic properties with changing Ce contents.Therefore,they can be used to meet many different application requirements from packaging market to driving motors,etc.The intrinsic magnetic properties,phase composition,and microstructures of the Ce-based sintered magnets with different Ce contents have been summarized.The service performances such as temperature stability,corrosion resistance,mechanical properties and thermal expansion of commercial Ce-based sintered magnets are introduced.The research and development trends of the Ce-based magnets in the future are pointed out.
基金This research was made possible as a result of a generous grant from Shenzhen Nobel Prize Scientists Laboratory Project(grant no.C17213101)Guangdong Provincial Key Laboratory of Catalysis(no.2020B121201002)+1 种基金Guangdong Provincial Key Laboratory of Energy Materials for Electric Power(no.2018B030322001)China Postdoctoral Science Foundation(no.2018M642133).
文摘Non-noble metal catalysts are suitable for the oxygen evolution reaction(OER)owing to their original oxidation states and oxygen coordination environments,which can regulate the adsorption of OH−at the active sites to facilitate the formation of oxygencontaining intermediates.However,the difficulties encountered in the conversion of intermediates(M–OH,M–O,and M–OOH)lead to low efficiency.Decorations of transition metal catalysts with foreign elements are regarded effective solutions,among which decoration with Ce-based materials(CeBM)is the most prominent.This review investigates the current status and future prospects of CeBM-decorated transition metal electrocatalysts.By presenting a thorough account of the latest development,we aim to set a common ground for the research community for a deeper understanding of the roles of CeBM that originate from its unique electronic structure and abundant oxygen vacancies.Moreover,we wish to provide our own perspectives as to how to further the design of Ce-based OER electrocatalysts and where such catalysts may be applied in fields beyond electrocatalysis.
基金supported by the National Natural Science Foundation of China(Grant Nos.51171055 and 51322103)
文摘The isothermal crystallization behaviors in a newly developed CeGaCu bulk metallic glass have been investigated through the classic differential scanning calorimeter （DSC） method. It is found that the apparent activation energy （Ea） strongly depends on the fraction （x） of isothermal crystallization. Johnson-Mehl-Avrami （JMA） formula was used to analyze the mechanism of crystallization and the obtained Avrami exponent （n） was discovered to show an obvious correlation with the crystallization fraction x. With the help of the relation between Ea and n, the nucleation and growth activation energies, En and Eg, were estimated to be 214-304 kJ/mol and 91 kJ/mol, respectively. This result suggests that the main energy barrier against crystallization in the present glass should be the nucleation of nucleates, rather than the growth of crystals. Such a large E, is also believed to be responsible for the good glass forming ability of the CeGaCu alloy.
文摘我们采用柠檬酸配合法制备了Ce基复合氧化物催化剂,分别在热重分析仪(TG)和管式反应器中测试了其氧化碳烟及同时脱除NOx的催化活性;并利用XRD、BET、H2-TPR、XPS表征手段考察其结构.其中,Co0.1/C e La0.05复合氧化物同时催化去除碳烟和NOx的性能最佳,碳烟脱除率为50%的反应温度为301℃,N2产率为41.4%.实验结果表明,Co主要以氧化物形式均匀分散在Ce-La固溶体表面,Co3+与Co2+价态共存,离子间的变价有利于提高催化剂的氧化还原性能,有效降低了碳烟的起燃温度.La的引入增大了催化剂的比表面积,抑制了Ce O2晶粒长大,进而提高了N2产率.部分La和Co形成了微量的La Co O3,形成了更多氧空位,有利于提高催化氧化碳烟的活性.
