The chemical transformation of CO_(2) produces carbon compounds that can be used as precursors for the production of chemicals and fuels.Here,we investigated the activity and selectivity of the transition metals(Fe,Co...The chemical transformation of CO_(2) produces carbon compounds that can be used as precursors for the production of chemicals and fuels.Here,we investigated the activity and selectivity of the transition metals(Fe,Co,and Ni)supported on CeO_(2) catalyst for CO_(2) hydrogenation at atmospheric pressure.We found that Ni/CeO_(2) shows the highest CO_(2)conversion compared with Fe/CeO_(2) and Co/CeO_(2).Besides,Co/CeO_(2)and Ni/CeO_(2) exhibit nearly 100%CH_(4)selectivity while Fe/CeO_(2) inclines to produce CO.The characterization results show that the metal-support interaction order is Fe/CeO_(2)>Co/CeO_(2)>Ni/CeO_(2),the weak metal-support inte raction over Ni/CeO_(2)benefits the activation of H_(2) and then promotes the activity of CO_(2) hydrogenation.Additionally,in situ DRIFTS results demonstrate that monodentate formate species rather than bidentate formate are the active intermediates.The main route of CO_(2) hydrogenation to CH_(4) is that CO_(2) is firstly transformed to m-HCOO*and then direct hydrogenation of the m-HCOO*to CH_(4).This study provides insights into the understanding of the mechanisms of CO_(2) hydrogenation on CeO_(2)based catalysts.展开更多
The shape impact of nanostructured ceria on the dispersion of Pd species was investigated by analyzing the atomic configuration and the bonding environment of Pd species over spherical and cubic ceria particles,using ...The shape impact of nanostructured ceria on the dispersion of Pd species was investigated by analyzing the atomic configuration and the bonding environment of Pd species over spherical and cubic ceria particles,using STEM and XPS.Amorphous Pd particles of about 2.0 nm,with a substantial amount of tiny Pd species,dispersed on spherical ceria,primarily due to the enriched surface oxygen vacancies that bonded the Pd species tightly.While faceted Pd particles of about 2.9 nm located on cubic ceria with distinct interfaces where Pd atoms embedded into the ceria lattice.The crystalline Pd particles on ceria cubes were highly active and stable for methane combustion that occurred on the metal surface via a facile PdO/Pd redox cycle;while the amorphous Pd particles on spherical ceria particles were featured by a significantly higher activity and stability towards CO oxidation,where the Pd-ceria interface served as the active sites.展开更多
The development of direct methanol fuel cells(DMFCs) is partially limited by the poor kinetics of methanol oxidation reaction(MOR) at the anode side.It was reported that the interaction between Pt and CeO_(2) enhances...The development of direct methanol fuel cells(DMFCs) is partially limited by the poor kinetics of methanol oxidation reaction(MOR) at the anode side.It was reported that the interaction between Pt and CeO_(2) enhances the electrocatalytic performance of Pt catalyst for MOR.In this work,a hybrid material(CeO_(2)-C) composed of CeO_(2) and carbon was successfully prepared by a simple hydrothermal method followed by calcination in inert atmosphere.The hierarchically porous nanostructure and especially good electronic conductivity of CeO_(2)-C make it an excellent support for Pt particles for application in electrocatalytic process.TEM investigation reveals that triple-phase interface of Pt,carbon and CeO_(2) forms in Pt/CeO_(2)-C catalyst.Performance of the as-prepared catalyst for MOR was studied in alkaline medium.The Pt/CeO_(2)-C catalyst shows superior catalytic performance for MOR compared with Pt/CeO_(2) and the physical mixture of Pt/CeO_(2) and acetylene black(Pt/CeO_(2)+C).The significantly improved performance can be attributed to the synergetic effect between Pt particles and CeO_(2)-C support,and the better conductivity of CeO_(2)-C.This study provides a possible method to expand the application potential of CeO_(2) materials in MOR,and may also be used in other electrocatalytic process.展开更多
Developing high-performance ammonia decomposition catalysts for preparing COx-free hydrogen shows great practical significance.Herein,CeO_(2) is used as a promoter to modulate the metal-support interaction to enhance ...Developing high-performance ammonia decomposition catalysts for preparing COx-free hydrogen shows great practical significance.Herein,CeO_(2) is used as a promoter to modulate the metal-support interaction to enhance the catalytic performance of Ru/Al_(2)O_(3) catalysts.A series of 1Ru/xCe-10AI(x=0.5,1,or 3)catalysts was prepared by a facile colloidal deposition method.We find that the optimized 1 Ru/1Ce-10Al catalyst exhibits excellent activity for the decomposition of ammonia with a very high hydrogen yield of7097 mmolH2/(gRu·min)at 450℃.It is confirmed that Ru species are highly dispersed on the support surface as stable small clusters(~1.3 nm).More importantly,due to the interaction between Ru species and partially reduced CeO_(2-x),the electron density of Ru species is increased,which is beneficial to the high activity of the 1 Ru/xCe-10Al catalysts.This work paves a way to construct high-efficiency ammonia decomposition catalysts modified by CeO_(2).展开更多
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
Searching for highly efficient catalysts toward dehydrogenation of hydrazine for chemical hydrogen storage is highly desirable for the development of hydrogen economy. Herein, we report a simple in situ co-reduction s...Searching for highly efficient catalysts toward dehydrogenation of hydrazine for chemical hydrogen storage is highly desirable for the development of hydrogen economy. Herein, we report a simple in situ co-reduction synthesis of NiPt nanoparticles supported on CeO_2 nanospheres and their superior catalytic performance for hydrogen generation from alkaline solution of hydrazine at room temperature. Thanks to the strong electronic interaction arising from synergistic effect at atomic lever and support-metal interaction between NiPt and CeO_2.The obtained Ni_5Pt_5-CeO_2 catalyst exhibits 100% hydrogen selectivity and superior catalytic performance for hydrogen generation from alkaline solution of hydrazine at room temperature, with a TOF value of 416 h 1.展开更多
基金Project supported by the Yunnan Fundamental Research Projects(202101BE070001-001)the Special Project of Eco-Environmental Technology for Emission Peak&Carbon Neutralization(RCEES-TDZ-2021-4)the National Natural Science Foundation of China(22276204,21976196).
文摘The chemical transformation of CO_(2) produces carbon compounds that can be used as precursors for the production of chemicals and fuels.Here,we investigated the activity and selectivity of the transition metals(Fe,Co,and Ni)supported on CeO_(2) catalyst for CO_(2) hydrogenation at atmospheric pressure.We found that Ni/CeO_(2) shows the highest CO_(2)conversion compared with Fe/CeO_(2) and Co/CeO_(2).Besides,Co/CeO_(2)and Ni/CeO_(2) exhibit nearly 100%CH_(4)selectivity while Fe/CeO_(2) inclines to produce CO.The characterization results show that the metal-support interaction order is Fe/CeO_(2)>Co/CeO_(2)>Ni/CeO_(2),the weak metal-support inte raction over Ni/CeO_(2)benefits the activation of H_(2) and then promotes the activity of CO_(2) hydrogenation.Additionally,in situ DRIFTS results demonstrate that monodentate formate species rather than bidentate formate are the active intermediates.The main route of CO_(2) hydrogenation to CH_(4) is that CO_(2) is firstly transformed to m-HCOO*and then direct hydrogenation of the m-HCOO*to CH_(4).This study provides insights into the understanding of the mechanisms of CO_(2) hydrogenation on CeO_(2)based catalysts.
文摘The shape impact of nanostructured ceria on the dispersion of Pd species was investigated by analyzing the atomic configuration and the bonding environment of Pd species over spherical and cubic ceria particles,using STEM and XPS.Amorphous Pd particles of about 2.0 nm,with a substantial amount of tiny Pd species,dispersed on spherical ceria,primarily due to the enriched surface oxygen vacancies that bonded the Pd species tightly.While faceted Pd particles of about 2.9 nm located on cubic ceria with distinct interfaces where Pd atoms embedded into the ceria lattice.The crystalline Pd particles on ceria cubes were highly active and stable for methane combustion that occurred on the metal surface via a facile PdO/Pd redox cycle;while the amorphous Pd particles on spherical ceria particles were featured by a significantly higher activity and stability towards CO oxidation,where the Pd-ceria interface served as the active sites.
基金Project supported by the China Postdoctoral Science Foundation(2018M633136)Industry and Information Technology Bureau of Shenzhen Municipality(201901171518)。
文摘The development of direct methanol fuel cells(DMFCs) is partially limited by the poor kinetics of methanol oxidation reaction(MOR) at the anode side.It was reported that the interaction between Pt and CeO_(2) enhances the electrocatalytic performance of Pt catalyst for MOR.In this work,a hybrid material(CeO_(2)-C) composed of CeO_(2) and carbon was successfully prepared by a simple hydrothermal method followed by calcination in inert atmosphere.The hierarchically porous nanostructure and especially good electronic conductivity of CeO_(2)-C make it an excellent support for Pt particles for application in electrocatalytic process.TEM investigation reveals that triple-phase interface of Pt,carbon and CeO_(2) forms in Pt/CeO_(2)-C catalyst.Performance of the as-prepared catalyst for MOR was studied in alkaline medium.The Pt/CeO_(2)-C catalyst shows superior catalytic performance for MOR compared with Pt/CeO_(2) and the physical mixture of Pt/CeO_(2) and acetylene black(Pt/CeO_(2)+C).The significantly improved performance can be attributed to the synergetic effect between Pt particles and CeO_(2)-C support,and the better conductivity of CeO_(2)-C.This study provides a possible method to expand the application potential of CeO_(2) materials in MOR,and may also be used in other electrocatalytic process.
基金Project supported by the National Key Basic Research Program of China(2021YFA1501103)the National Science Fund for Distinguished Young Scholars of China(22225110)+1 种基金the National Natural Science Foundation of China(22075166,22271177)the Taishan Scholar Project of Shandong Province of China,and the Young Scholars Program of Shandong University.
文摘Developing high-performance ammonia decomposition catalysts for preparing COx-free hydrogen shows great practical significance.Herein,CeO_(2) is used as a promoter to modulate the metal-support interaction to enhance the catalytic performance of Ru/Al_(2)O_(3) catalysts.A series of 1Ru/xCe-10AI(x=0.5,1,or 3)catalysts was prepared by a facile colloidal deposition method.We find that the optimized 1 Ru/1Ce-10Al catalyst exhibits excellent activity for the decomposition of ammonia with a very high hydrogen yield of7097 mmolH2/(gRu·min)at 450℃.It is confirmed that Ru species are highly dispersed on the support surface as stable small clusters(~1.3 nm).More importantly,due to the interaction between Ru species and partially reduced CeO_(2-x),the electron density of Ru species is increased,which is beneficial to the high activity of the 1 Ru/xCe-10Al catalysts.This work paves a way to construct high-efficiency ammonia decomposition catalysts modified by CeO_(2).
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financially supported by the National Natural Science Foundation of China (No. 21571145)Large-scale Instrument and Equipment Sharing Foundation of Wuhan University
文摘Searching for highly efficient catalysts toward dehydrogenation of hydrazine for chemical hydrogen storage is highly desirable for the development of hydrogen economy. Herein, we report a simple in situ co-reduction synthesis of NiPt nanoparticles supported on CeO_2 nanospheres and their superior catalytic performance for hydrogen generation from alkaline solution of hydrazine at room temperature. Thanks to the strong electronic interaction arising from synergistic effect at atomic lever and support-metal interaction between NiPt and CeO_2.The obtained Ni_5Pt_5-CeO_2 catalyst exhibits 100% hydrogen selectivity and superior catalytic performance for hydrogen generation from alkaline solution of hydrazine at room temperature, with a TOF value of 416 h 1.
