The water gas shift reaction is of vital significance for the generation and transition of energy due to the application in hydrogen production and industries such as ammonia synthesis and fuel cells.The influence of ...The water gas shift reaction is of vital significance for the generation and transition of energy due to the application in hydrogen production and industries such as ammonia synthesis and fuel cells.The influence of support doping and bimetallic alloying on the catalytic performance of Pt/Ce O_(2)-based nanocatalysts in water gas shift reaction was reported in this work.Various lanthanide ions and 3d transition metals were respectively introduced into the Ce O_(2)support or Pt to form Pt/Ce O_(2):Ln(Ln=La,Nd,Gd,Tb,Yb)and Pt M/Ce O_(2)(M=Fe,Co,Ni)nanocatalysts.The sample of Pt/Ce O_(2):Tb showed the highest activity(TOF at 200℃=0.051 s^(-1))among the Pt/Ce O_(2):Ln and the undoped Pt/Ce O_(2)catalysts.Besides,the sample of Pt Fe/Ce O_(2)exhibited the highest activity(TOF at 200℃=0.12 s^(-1))among Pt M/Ce O_(2)catalysts.The results of the multiple characterizations indicated that the catalytic activity of Pt/Ce O_(2):Ln catalysts was closely correlated with the amount of oxygen vacancies in doped ceria support.However,the different activity of Pt M/Ce O_(2)bimetallic catalysts was owing to the various Pt oxidation states of the bimetals dispersed on ceria.The study of the reaction pathway indicated that both the samples of Pt/Ce O_(2)and Pt/Ce O_(2):Tb catalyzed the reaction through the formate pathway,and the enhanced activity of the latter derived from the increased concentration of oxygen vacancies along with promoted water dissociation.As for the sample of Pt Fe/Ce O_(2),its catalytic mechanism was the carboxyl route with a higher reaction rate due to the moderate valence of Pt along with improved CO activation.展开更多
In this study,Ni catalysts supported on Pr-doped Ce O_(2) are studied for the CO_(2) methanation reaction and the effect of Pr doping on the physicochemical properties and the catalytic performance is thoroughly evalu...In this study,Ni catalysts supported on Pr-doped Ce O_(2) are studied for the CO_(2) methanation reaction and the effect of Pr doping on the physicochemical properties and the catalytic performance is thoroughly evaluated.It is shown,that Pr^(3+)ions can substitute Ce^(4+)ones in the support lattice,thereby introducing a high population of oxygen vacancies,which act as active sites for CO_(2) chemisorption.Pr doping can also act to reduce the crystallite size of metallic Ni,thus promoting the active metal dispersion.Catalytic performance evaluation evidences the promoting effect of low Pr loadings(5 at%and 10 at%)towards a higher catalytic activity and lower CO_(2) activation energy.On the other hand,higher Pr contents negate the positive effects on the catalytic activity by decreasing the oxygen vacancy population,thereby creating a volcano-type trend towards an optimum amount of aliovalent substitution.展开更多
A series of monolithic Ni/CeO_2-ZrO_2/γ-Al_2O_3 catalysts for the POM reaction were prepared. The activity test shows that the catalyst has the best performance when CeO_2-ZrO_2 content is 8 wt%.The synergistic actio...A series of monolithic Ni/CeO_2-ZrO_2/γ-Al_2O_3 catalysts for the POM reaction were prepared. The activity test shows that the catalyst has the best performance when CeO_2-ZrO_2 content is 8 wt%.The synergistic actions between CeO_2-ZrO_2 and γ-Al_2O_3 improve highly catalytic activity by increasing CH_4 conversion, H_2 and CO selectivity. XPS analysis of the used catalyst indicates that there coexist Ce^(4+) and Ce^(3+).展开更多
The size of the nanoparticles and the number of oxygen vacancies have a significant effect on the catalytic activity of copper-based catalysts used for the synthesis of methanol from syngas.In this study,the authors p...The size of the nanoparticles and the number of oxygen vacancies have a significant effect on the catalytic activity of copper-based catalysts used for the synthesis of methanol from syngas.In this study,the authors prepared a series of catalysts CuO/ZnO/Al_(2)O_(3)/CeO_(2)(CZAC)with CuO particles of different sizes and varying number of oxygen vacancies on the surface by changing the added volume of CeO2 by using the co-precipitation method.The properties of the catalysts were characterized and their activity was evaluated by using high-pressure fixed-bed reaction equipment.The results showed that the addition of CeO_(2)to CuO/ZnO/Al_(2)O_(3)not only influenced the size of the CuO particles and metal-metal interactions,but also had an effect on the concentrations of oxygen vacancies and strongly basic sites.The presence of CuO particles of small sizes and a large numbers of oxygen vacancies on the surface of the catalyst were beneficial to its activity for the synthesis of methanol.The catalyst CZAC,when modified by 5%of CeO_(2),recorded CuO particles of the smallest size(8.9 nm),strong intermetallic interactions,and the highest concentrations of oxygen vacancies and strongly basic sites.It also exhibited the highest catalytic activity,with a space-time yield of methanol of 0.315 g/(h·g)that was higher than that of the enterprise RK-5 catalyst[0.215 g/(h·g)].展开更多
Developing an efficiently supported Cu-based catalyst with promoters to substitute the existing non-supported Cu-based catalysts is highly desirable to the Rochow-Müller reaction. Using a simple ball-milling meth...Developing an efficiently supported Cu-based catalyst with promoters to substitute the existing non-supported Cu-based catalysts is highly desirable to the Rochow-Müller reaction. Using a simple ball-milling method and CeO_(2) support, we prepared a high-performance CuO-ZnO-P-Sn/CeO_(2) catalyst by integrating highly dispersed multicomponent promoters of ZnO, Sn, and P with the active component CuO. This catalyst shows a significantly enhanced dimethyldichlorosilane selectivity because these promoters can substantially increase the Cu+ content and the formation of an active CuxSi phase. This work provides a new approach to efficiently designing Cu-based catalysts for the Rochow-Müller reaction.展开更多
气氛环境下原位研究催化剂的烧结行为,能够为理解催化剂在预处理以及反应条件下的烧结机理和高稳定催化剂的设计提供重要的实验依据。本文以Au/CeO_(2)模型纳米催化剂为研究对象,利用环境透射电子显微镜原位观察其在O_(2)与CO气氛下的...气氛环境下原位研究催化剂的烧结行为,能够为理解催化剂在预处理以及反应条件下的烧结机理和高稳定催化剂的设计提供重要的实验依据。本文以Au/CeO_(2)模型纳米催化剂为研究对象,利用环境透射电子显微镜原位观察其在O_(2)与CO气氛下的高温动态烧结过程。实验发现,负载在CeO_(2)上的Au纳米颗粒在O_(2)与CO气氛环境中表现出不同的烧结行为,其在O_(2)气氛下具有较高的烧结速度,同时存在颗粒迁移与聚集长大(particle migration and coalescence,PMC)和奥斯特瓦尔德熟化(Ostwald ripening,OR)两种烧结过程;在CO气氛下烧结速度较慢,烧结过程以OR为主。对比不同气氛环境下烧结后催化剂的表面结构可知,CO增加了CeO_(2)表面台阶的数量以及表面氧空位浓度,增强了载体对Au颗粒的锚定作用,从而提升Au/CeO_(2)催化剂的稳定性。展开更多
Dehydrogenation of ethane to ethylene in CO_2 was investigated overCeO_2/γ-Al_2O_3 catalysts at 700℃ in a conventional flow reactor operating at atmosphericpressure. XRD, BET and microcalori-metric adsorption techni...Dehydrogenation of ethane to ethylene in CO_2 was investigated overCeO_2/γ-Al_2O_3 catalysts at 700℃ in a conventional flow reactor operating at atmosphericpressure. XRD, BET and microcalori-metric adsorption techniques were used to characterize thestructure and surface acidity/basicity of the CeO_2/γ-Al_2O_3 catalysts. The results show that thesurface acidity decreased while the surface basicity increased after the addition of CeO_2 toγ-Al_2O_3. Accordingly, the activity of the hydrogenation reaction of CO_2 increased, which mightbe responsible for the enhanced conversion in the dehydrogenation of ethane to ethylene. The highestethane conversion obtained was about 15% for the 25%CeO_2/γ-Al_2O_3. The selectivity to ethylenewas high for all the CeO_2, γ-Al_2O_3 and CeO2/γ-Al_2O_3 catalysts.展开更多
基金financial support from the National Natural Science Foundation of China(21832001 and 21771009)the Beijing National Laboratory for Molecular Sciences(BNLMSCXXM-202104)。
文摘The water gas shift reaction is of vital significance for the generation and transition of energy due to the application in hydrogen production and industries such as ammonia synthesis and fuel cells.The influence of support doping and bimetallic alloying on the catalytic performance of Pt/Ce O_(2)-based nanocatalysts in water gas shift reaction was reported in this work.Various lanthanide ions and 3d transition metals were respectively introduced into the Ce O_(2)support or Pt to form Pt/Ce O_(2):Ln(Ln=La,Nd,Gd,Tb,Yb)and Pt M/Ce O_(2)(M=Fe,Co,Ni)nanocatalysts.The sample of Pt/Ce O_(2):Tb showed the highest activity(TOF at 200℃=0.051 s^(-1))among the Pt/Ce O_(2):Ln and the undoped Pt/Ce O_(2)catalysts.Besides,the sample of Pt Fe/Ce O_(2)exhibited the highest activity(TOF at 200℃=0.12 s^(-1))among Pt M/Ce O_(2)catalysts.The results of the multiple characterizations indicated that the catalytic activity of Pt/Ce O_(2):Ln catalysts was closely correlated with the amount of oxygen vacancies in doped ceria support.However,the different activity of Pt M/Ce O_(2)bimetallic catalysts was owing to the various Pt oxidation states of the bimetals dispersed on ceria.The study of the reaction pathway indicated that both the samples of Pt/Ce O_(2)and Pt/Ce O_(2):Tb catalyzed the reaction through the formate pathway,and the enhanced activity of the latter derived from the increased concentration of oxygen vacancies along with promoted water dissociation.As for the sample of Pt Fe/Ce O_(2),its catalytic mechanism was the carboxyl route with a higher reaction rate due to the moderate valence of Pt along with improved CO activation.
基金support of this work by the project“Development of new innovative low carbon energy technologies to improve excellence in the Region of Western Macedonia”(MIS 5047197)which is implemented under the Action“Reinforcement of the Research and Innovation Infrastructure”funded by the Operational Program“Competitiveness,Entrepreneurship and Innovation”(NSRF 2014-2020)co-financed by Greece and the European Union(European Regional Development Fund)。
文摘In this study,Ni catalysts supported on Pr-doped Ce O_(2) are studied for the CO_(2) methanation reaction and the effect of Pr doping on the physicochemical properties and the catalytic performance is thoroughly evaluated.It is shown,that Pr^(3+)ions can substitute Ce^(4+)ones in the support lattice,thereby introducing a high population of oxygen vacancies,which act as active sites for CO_(2) chemisorption.Pr doping can also act to reduce the crystallite size of metallic Ni,thus promoting the active metal dispersion.Catalytic performance evaluation evidences the promoting effect of low Pr loadings(5 at%and 10 at%)towards a higher catalytic activity and lower CO_(2) activation energy.On the other hand,higher Pr contents negate the positive effects on the catalytic activity by decreasing the oxygen vacancy population,thereby creating a volcano-type trend towards an optimum amount of aliovalent substitution.
文摘A series of monolithic Ni/CeO_2-ZrO_2/γ-Al_2O_3 catalysts for the POM reaction were prepared. The activity test shows that the catalyst has the best performance when CeO_2-ZrO_2 content is 8 wt%.The synergistic actions between CeO_2-ZrO_2 and γ-Al_2O_3 improve highly catalytic activity by increasing CH_4 conversion, H_2 and CO selectivity. XPS analysis of the used catalyst indicates that there coexist Ce^(4+) and Ce^(3+).
基金supported by the Nature Science Foundation of China(Grant 22262006,22068009)the Supported by Guizhou Provincial Science and Technology Projects(ZK[2023]ordinary 050,[2023]General 403)+4 种基金the Science and Technology Support Plan Projects of Guizhou Province(Grant(2018)2192)the Scientific and Technological Innovation Talents Team of Guizhou(2018-5607)the Science and Technology Foundation of Guizhou Province(20177254)the One hundred Person Project of Guizhou Province(No.20165655)the Innovation Group Project of Education Department in Guizhou Province(No.2021010)。
文摘The size of the nanoparticles and the number of oxygen vacancies have a significant effect on the catalytic activity of copper-based catalysts used for the synthesis of methanol from syngas.In this study,the authors prepared a series of catalysts CuO/ZnO/Al_(2)O_(3)/CeO_(2)(CZAC)with CuO particles of different sizes and varying number of oxygen vacancies on the surface by changing the added volume of CeO2 by using the co-precipitation method.The properties of the catalysts were characterized and their activity was evaluated by using high-pressure fixed-bed reaction equipment.The results showed that the addition of CeO_(2)to CuO/ZnO/Al_(2)O_(3)not only influenced the size of the CuO particles and metal-metal interactions,but also had an effect on the concentrations of oxygen vacancies and strongly basic sites.The presence of CuO particles of small sizes and a large numbers of oxygen vacancies on the surface of the catalyst were beneficial to its activity for the synthesis of methanol.The catalyst CZAC,when modified by 5%of CeO_(2),recorded CuO particles of the smallest size(8.9 nm),strong intermetallic interactions,and the highest concentrations of oxygen vacancies and strongly basic sites.It also exhibited the highest catalytic activity,with a space-time yield of methanol of 0.315 g/(h·g)that was higher than that of the enterprise RK-5 catalyst[0.215 g/(h·g)].
基金support from the National Natural Science Foundation of China(Nos.21978299 and 21878301)supported by the Open Research Fund of State Key Laboratory of Multiphase Complex Systems(MPCS-2021-D-08)+2 种基金GRINM Group(G12620213102035)Y.J.thanks the financial support from the Outstanding Youth Cultivation Program of Beijing Technology and Business University(No.19008021144)the Research Foundation for Advanced Talents of Beijing Technology and Business University(No.19008020159).
文摘Developing an efficiently supported Cu-based catalyst with promoters to substitute the existing non-supported Cu-based catalysts is highly desirable to the Rochow-Müller reaction. Using a simple ball-milling method and CeO_(2) support, we prepared a high-performance CuO-ZnO-P-Sn/CeO_(2) catalyst by integrating highly dispersed multicomponent promoters of ZnO, Sn, and P with the active component CuO. This catalyst shows a significantly enhanced dimethyldichlorosilane selectivity because these promoters can substantially increase the Cu+ content and the formation of an active CuxSi phase. This work provides a new approach to efficiently designing Cu-based catalysts for the Rochow-Müller reaction.
文摘气氛环境下原位研究催化剂的烧结行为,能够为理解催化剂在预处理以及反应条件下的烧结机理和高稳定催化剂的设计提供重要的实验依据。本文以Au/CeO_(2)模型纳米催化剂为研究对象,利用环境透射电子显微镜原位观察其在O_(2)与CO气氛下的高温动态烧结过程。实验发现,负载在CeO_(2)上的Au纳米颗粒在O_(2)与CO气氛环境中表现出不同的烧结行为,其在O_(2)气氛下具有较高的烧结速度,同时存在颗粒迁移与聚集长大(particle migration and coalescence,PMC)和奥斯特瓦尔德熟化(Ostwald ripening,OR)两种烧结过程;在CO气氛下烧结速度较慢,烧结过程以OR为主。对比不同气氛环境下烧结后催化剂的表面结构可知,CO增加了CeO_(2)表面台阶的数量以及表面氧空位浓度,增强了载体对Au颗粒的锚定作用,从而提升Au/CeO_(2)催化剂的稳定性。
文摘Dehydrogenation of ethane to ethylene in CO_2 was investigated overCeO_2/γ-Al_2O_3 catalysts at 700℃ in a conventional flow reactor operating at atmosphericpressure. XRD, BET and microcalori-metric adsorption techniques were used to characterize thestructure and surface acidity/basicity of the CeO_2/γ-Al_2O_3 catalysts. The results show that thesurface acidity decreased while the surface basicity increased after the addition of CeO_2 toγ-Al_2O_3. Accordingly, the activity of the hydrogenation reaction of CO_2 increased, which mightbe responsible for the enhanced conversion in the dehydrogenation of ethane to ethylene. The highestethane conversion obtained was about 15% for the 25%CeO_2/γ-Al_2O_3. The selectivity to ethylenewas high for all the CeO_2, γ-Al_2O_3 and CeO2/γ-Al_2O_3 catalysts.
