In this study,the support effects on the Pd-catalyzed semi-hydrogenation of acetylene have been investigated from the structural and kinetic perspectives.According to the results of kinetic analysis and X-ray photoele...In this study,the support effects on the Pd-catalyzed semi-hydrogenation of acetylene have been investigated from the structural and kinetic perspectives.According to the results of kinetic analysis and X-ray photoelectron spectroscopy,hydrogen temperature-programmed reduction,temperature-programmed hydride decomposition,and in situ X-ray diffraction measurements,using carbon nanotubes as support for Pd nanocatalysts with various sizes instead of a-Al_(2)O_(3) decreases the Pd^(0)3d binding energy and suppresses the formation of undesirable palladium hydride species,thus increasing the ethylene yield.Furthermore,X-ray absorption spectroscopy,high-resolution transmission electron microscopy,and C_(2)H_(4) temperature-programmed desorption studies combined with density-functional theory calculations reveal the existence of a unique Pd local environment,containing subsurface carbon atoms,that produces positive geometric effects on the acetylene conversion reaction.Therefore,tailoring the Pd local environment and electronic properties represents an effective strategy for the fabrication and design of highly active and selective Pd semi-hydrogenation catalysts.展开更多
Au/Ce1xZrxO2 catalysts (x=0-0.8) were prepared by a deposition-precipitation method using Ce1xZrxO2 nanoparticles as supports with variable Ce and Zr contents. Their structures were characterized by complimentary mean...Au/Ce1xZrxO2 catalysts (x=0-0.8) were prepared by a deposition-precipitation method using Ce1xZrxO2 nanoparticles as supports with variable Ce and Zr contents. Their structures were characterized by complimentary means such as X-ray diffraction, Raman, scanning transmission electron microscopy and X-ray photoelectron spectroscopy (XPS). These Au catalysts possessed similar sizes and crystalline phases of Ce1xZrxO2 supports as well as similar sizes and oxidation states of Au nanoparticles. The oxidation state of Au nanoparticles was dominated by Au 0 especially in CO oxidation. Their activities were examined in CO oxidation at different temperatures in the range of 303 333 K. The CO oxidation rates normalized per Au atoms increased with the increasing Ce contents, and reached the maximum value over Au/CeO2. Such change was in parallel with the change in the oxygen storage capacity values, i.e. the amounts of active oxygen species on Au/Ce1xZrxO2 catalysts. The excellent correlation between the two properties of the catalysts suggests that the intrinsic support effects on the CO oxidation rates is related to the effects on the adsorption and activation of O2 on Au/Ce1xZrxO2 catalysts. Such understanding on the support effects may be useful for designing more active Au catalysts, for example, by tuning the redox properties of oxide supports.展开更多
In the course of investigating the catalytic behavior of metal complexes forring opening metathesis polymerization of cycloolefins, metathesis, hydroformylation andselective hydrogenation of olefins experimental resul...In the course of investigating the catalytic behavior of metal complexes forring opening metathesis polymerization of cycloolefins, metathesis, hydroformylation andselective hydrogenation of olefins experimental results time and again indicate the pres-ence of effects of macromolecular supports -the utilization of macromolecular supportsincreases obviously the activity, selectivity, and stability of the catalysts and so as to in-crease the conversion of substrates, yields of reactions, properties of formed polymers andso on. Discussed these effects on the basis of the authors’ experiments.展开更多
Ligand-protected gold(Au_(n))clusters sometimes need the removal of organic ligands to expose more active sites and reduce steric hindrance in catalytic reactions,and large amount of organic and inorganic materials us...Ligand-protected gold(Au_(n))clusters sometimes need the removal of organic ligands to expose more active sites and reduce steric hindrance in catalytic reactions,and large amount of organic and inorganic materials usually need to be employed as supports to anchor Aun clusters through different interaction mechanisms.Whereas,less comprehensive summaries have been provided about the crucial contribution of various supports to the catalytic performance of the supported Aun clusters.Herein,this review firstly summarizes synthesis methods(e.g.,impregnation and encapsulation processes)for the supported Aun cluster catalysts,and then mainly points out specific contributions of support effect in a great diversity of catalytic reactions,as well as deep interaction mechanisms.Besides,opportunities and challenging issues will be stated towards supported Aun clusters,in terms of improving catalytic performance and structural stability of Aun clusters inthedemand of catalysis.展开更多
Aqueous-phase reforming(APR)is an attractive process to produce bio-based hydrogen from waste biomass streams,during which the catalyst stability is often challenged due to the harsh reaction conditions.In this work,t...Aqueous-phase reforming(APR)is an attractive process to produce bio-based hydrogen from waste biomass streams,during which the catalyst stability is often challenged due to the harsh reaction conditions.In this work,three Pt-based catalysts supported on C,AlO(OH),and ZrO_(2)were investigated for the APR of hydroxyacetone solution in afixed bed reactor at 225℃and 35 bar.Among them,the Pt/C catalyst showed the highest turnover frequency for H_(2)production(TOF of 8.9 molH_(2)molPt^(-1)min^(-1))and the longest catalyst stability.Over the AlO(OH)and ZrO_(2)supported Pt catalysts,the side reactions consuming H_(2),formation of coke,and Pt sintering result in a low H_(2)production and the fast catalyst deactivation.The proposed reaction pathways suggest that a promising APR catalyst should reform all oxygenates in the aqueous phase,minimize the hydrogenation of the oxygenates,maximize the WGS reaction,and inhibit the condensation and coking reactions for maximizing the hydrogen yield and a stable catalytic performance.展开更多
Gold catalysts supported on Mg-Al mixed oxides for oxidative esterification of methacrolein are prepared by impregnation.Effects of the support particle size,concentration of HAuCl4 solution and Mg/Al ratio on gold lo...Gold catalysts supported on Mg-Al mixed oxides for oxidative esterification of methacrolein are prepared by impregnation.Effects of the support particle size,concentration of HAuCl4 solution and Mg/Al ratio on gold loading and catalytic properties are investigated.The catalysts are characterized by CO_(2)-TPD,EDS,XPS,STEM and XRD techniques.Catalysts with smaller support particle size show more uniform gold distribution and higher gold dispersion,resulting in a higher catalytic performance,and the uniformity of gold and the activity of the catalysts with larger support particle size can be improved by decreasing the concentration of HAuCl4 solution.The Mg/Al molar ratio has significant effect on the uniformity of gold and the activity of the catalyst,and the optimum Mg/Al molar ratio is 0.1–0.2.This study underlines the importance of engineering support particle size,concentration of HAuCl4 solution and density of adsorption sites for efficient gold loading on support by impregnation.展开更多
Recently,the arguments raised by Gang and Jing have been published in Chinese Journal of Integrative Medicine,(1)concerning the randomized controlled trial(RCT)of our team published in JAMA.(2)The conclusions of Gang ...Recently,the arguments raised by Gang and Jing have been published in Chinese Journal of Integrative Medicine,(1)concerning the randomized controlled trial(RCT)of our team published in JAMA.(2)The conclusions of Gang and Jing(1)result not only from misunderstanding of the aims of our study,(2)but also a lack of basic knowledge for the design of RCT and the limitations on the content,and hence the length,of the primary outcome article in high-impact journals(i.e.2。展开更多
The mechanical effects of bolt-mesh-anchor coupling support in deep tunnels were studied by using a numerical method, based on deep tunnel coupling supporting techniques and non-linear deformation mechanical theory of...The mechanical effects of bolt-mesh-anchor coupling support in deep tunnels were studied by using a numerical method, based on deep tunnel coupling supporting techniques and non-linear deformation mechanical theory of rock mass at great depths.It is shown that the potential of a rigid bolt support can be efficiently activated through the coupling effect between a bolt-net support and the surrounding rock.It is found that the accumulated plastic energy in the surrounding rock can be sufficiently transformed by the coupling effect of a bolt-mesh-tray support.The strength of the surrounding rock mass can be mobilized to control the deforma-tion of the surrounding rock by a pre-stress and time-space effect of the anchor support.The high stress transformation effect can be realized by the mechanical coupling effect of the bolt-mesh-anchor support, whereby the force of the support and deformation of the surrounding rock tends to become uniform, leading to a sustained stability of the tunnel.展开更多
Supporting Pd catalysts characterized significant different size distribution were obtained using PdCl2,[Pd(NH3)4](NO3)2 and Pd(acac)2 as precursors.High-resolution transmission electron microscopy(TEM),X-ray diffract...Supporting Pd catalysts characterized significant different size distribution were obtained using PdCl2,[Pd(NH3)4](NO3)2 and Pd(acac)2 as precursors.High-resolution transmission electron microscopy(TEM),X-ray diffraction(XRD),in-situ Fourier transform infrared spectroscopy(FTIR) and Raman spectroscopy were used to examine the dispersion of Pd.Catalytic performance measurements show that the activities for CO oxidation increase as the Pd particle size decreases and the O2/CO ratio increases.The activities under oxygen rich conditions are significantly higher than those at near the stoichiometric conditions.Pd on TiO2 prepared by the Pd(acac)2 precursor is highly dispersed,leading to a considerable activity for CO oxidation at near room temperature.CO oxidation on the 1 wt% Pd/TiO2 and under an O2/CO ratio of 1 characterized an apparent activation energy of 36.7 kJ/mol,which is closed to those reported for CO oxidation on the supported Au catalysts.The present work demonstrates a high catalytic activity of highly dispersed noble metals,and suggests a promising approach of using noble metals as catalysts with exceeding high efficiency.展开更多
Achieving effective interaction can the students get good learning results,and enhance the quality of distance learning.The paper firstly analyzes the research on distance learning support services and the problems of...Achieving effective interaction can the students get good learning results,and enhance the quality of distance learning.The paper firstly analyzes the research on distance learning support services and the problems of distance learning interaction in order to clarify the significance of implementing effective interaction.Then it puts forward the learning support services strategies based on effective interaction,which means to promote distance learning interaction and enhance the students'self-learning ability.展开更多
The effect of mixed oxide support on the performance of Ni/ZnO in the reactive adsorption desulfurization(RADS) reaction was investigated in a fixed bed reactor by using thiophene as the sulfur-containing compound in ...The effect of mixed oxide support on the performance of Ni/ZnO in the reactive adsorption desulfurization(RADS) reaction was investigated in a fixed bed reactor by using thiophene as the sulfur-containing compound in the model gasoline. A series of oxide supports for Ni/ZnO were synthesized by the co-precipitation method and characterized by XRD, N_2-adsorption, TPR and NH_3-TPD techniques. It was found that the desulfurization capacity of Ni/ZnO was enhanced greatly when active components were supported on the proper mixed oxide. Ni/ZnO supported on oxides exhibited much higher desulfurization efficiency and sulfur adsorption capacity than the unsupported Ni/ZnO and the synthesized Ni/ZnO-SA adsorbent exhibited the highest efficiency for thiophene removal. The higher desulfurization activity and sulfur capacity of Ni/ZnO supported on SiO_2-Al_2O_3 with small particle size, high specific surface area and large pore volume could promote the high dispersion of active metal phase and the transfer of sulfur to ZnO with lower mass transfer resistance. γ-Al_2O_3 species could weaken the interaction of active phases and SiO_2 as well as could increase greatly the amount of weak acids. Therefore, these oxides could impose a great influence on the structure and chemical properties of the catalyst.展开更多
Graphite intercalation compounds(GIC) were tested as an experimental model for studying the electronic effect of carbon support on the catalytic activity and poisoning tolerance of Pt catalyst for direct methanol fuel...Graphite intercalation compounds(GIC) were tested as an experimental model for studying the electronic effect of carbon support on the catalytic activity and poisoning tolerance of Pt catalyst for direct methanol fuel cells. The GIC samples with different intercalation degrees were prepared by electrolyzing graphite flake in H2SO4 for varying the periods of time. The GIC-supported Pt catalyst was deposited electrochemically. The catalytic activity and poisoning tolerance of the GIC-supported Pt catalysts were evaluated. It was found that GIC with sulfate anion as intercalate was able to catalyze methanol electrooxidation, which could be related to the positive charges generated on the graphite layer upon intercalation. As intercalation degree increased, the catalytic activity of the GIC-supported Pt catalyst decreased while the poisoning tolerance improved. This suggests that electron donation from support to catalyst had great effect on both catalytic activity and poisoning tolerance of Pt catalyst. And intercalation can be adopted as another important way to make modification on carboneous catalyst support.展开更多
The paper firstly analyzes the problems of distance learning interaction in order to clarify the significance of implementing effective interaction.Then it puts forward the learning support services strategies based o...The paper firstly analyzes the problems of distance learning interaction in order to clarify the significance of implementing effective interaction.Then it puts forward the learning support services strategies based on effective interaction,which means to design strategies from the perspective of effective interaction to improve the effect of distance learning.展开更多
The ditheion coefficients(Dapp) and the heterogeneous electron-transfer rate constan(ks)for ferrocene in MPEG/salt electrolytes were determined by using Steady-stae voltammetry. The temperature dependence of the two p...The ditheion coefficients(Dapp) and the heterogeneous electron-transfer rate constan(ks)for ferrocene in MPEG/salt electrolytes were determined by using Steady-stae voltammetry. The temperature dependence of the two parameters obeys the Arrhenius equstion. The effect of the ionic size of sir supporting electrolytes on diffusion and electron transfer dynamics of fermcene was展开更多
Objective:This study aimed to identify the mediation effects of health locus of control(HLC)and hope between stroke patients’social support and self-management.Methods:A cross-sectional study was conducted.A total of...Objective:This study aimed to identify the mediation effects of health locus of control(HLC)and hope between stroke patients’social support and self-management.Methods:A cross-sectional study was conducted.A total of 300 Chinese stroke patients were recruited by convenient sampling from the acupuncture department of two Chinese Traditional Medical Hospitals in Tianjin Province from June to September 2018.The self-report questionnaires include Social Support Assessment Scale,Herth Hope Index,Mental Health Locus of Control Scale,Stroke Self-management Behavior Scale,and personal information questionnaires.All the survey data were entered in Excel and analyzed using the SPSS 24.0 program.Mediation was tested with Bootstrapping in AMOS 23.0 program.Results:The result showed that internal health locus of control(IHLC),chance health locus of control(CHLC)and hope were the mediators between social support and self-management.The direct,indirect,and total effects of social support on self-management behavior were 0.306 (P<0.01),0.109(P<0.01),and 0.415(P<0.01),respectively.Conclusions:Social support can directly influence self-management,and it can also indirectly influence self-management through IHLC,CHLC,and hope.展开更多
基金This work was financially supported by the Natural Science Foundation of China(21922803,21776077,and 22008067)the Innovation Program of Shanghai Municipal Education Commission,the Shanghai Natural Science Foundation(17ZR1407300 and 17ZR1407500)+4 种基金the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning,the Shanghai Rising-Star Program(17QA1401200)the China Postdoctoral Science Foundation(2020M681202)the Open Project of State Key Laboratory of Chemical Engineering(SKLChe-15C03)the State Key Laboratory of Organic-Inorganic Composites(oic-201801007)the Fundamental Research Funds for the Central Universities(222201718003).
文摘In this study,the support effects on the Pd-catalyzed semi-hydrogenation of acetylene have been investigated from the structural and kinetic perspectives.According to the results of kinetic analysis and X-ray photoelectron spectroscopy,hydrogen temperature-programmed reduction,temperature-programmed hydride decomposition,and in situ X-ray diffraction measurements,using carbon nanotubes as support for Pd nanocatalysts with various sizes instead of a-Al_(2)O_(3) decreases the Pd^(0)3d binding energy and suppresses the formation of undesirable palladium hydride species,thus increasing the ethylene yield.Furthermore,X-ray absorption spectroscopy,high-resolution transmission electron microscopy,and C_(2)H_(4) temperature-programmed desorption studies combined with density-functional theory calculations reveal the existence of a unique Pd local environment,containing subsurface carbon atoms,that produces positive geometric effects on the acetylene conversion reaction.Therefore,tailoring the Pd local environment and electronic properties represents an effective strategy for the fabrication and design of highly active and selective Pd semi-hydrogenation catalysts.
基金the National Natural Science Foundation of China(20825310,20973011)the National Basic Research Program of China(973 Program,2011CB201400,2011CB808700)
文摘Au/Ce1xZrxO2 catalysts (x=0-0.8) were prepared by a deposition-precipitation method using Ce1xZrxO2 nanoparticles as supports with variable Ce and Zr contents. Their structures were characterized by complimentary means such as X-ray diffraction, Raman, scanning transmission electron microscopy and X-ray photoelectron spectroscopy (XPS). These Au catalysts possessed similar sizes and crystalline phases of Ce1xZrxO2 supports as well as similar sizes and oxidation states of Au nanoparticles. The oxidation state of Au nanoparticles was dominated by Au 0 especially in CO oxidation. Their activities were examined in CO oxidation at different temperatures in the range of 303 333 K. The CO oxidation rates normalized per Au atoms increased with the increasing Ce contents, and reached the maximum value over Au/CeO2. Such change was in parallel with the change in the oxygen storage capacity values, i.e. the amounts of active oxygen species on Au/Ce1xZrxO2 catalysts. The excellent correlation between the two properties of the catalysts suggests that the intrinsic support effects on the CO oxidation rates is related to the effects on the adsorption and activation of O2 on Au/Ce1xZrxO2 catalysts. Such understanding on the support effects may be useful for designing more active Au catalysts, for example, by tuning the redox properties of oxide supports.
基金The project was supported by the National Natural Science Foundation of China, "Macromolecular ligand effects of catalytic system for ring opening metathesis polymerization of dicydopentadiene" (Approval No. 29474160) & "Polymeric metal complex catalysts
文摘In the course of investigating the catalytic behavior of metal complexes forring opening metathesis polymerization of cycloolefins, metathesis, hydroformylation andselective hydrogenation of olefins experimental results time and again indicate the pres-ence of effects of macromolecular supports -the utilization of macromolecular supportsincreases obviously the activity, selectivity, and stability of the catalysts and so as to in-crease the conversion of substrates, yields of reactions, properties of formed polymers andso on. Discussed these effects on the basis of the authors’ experiments.
基金supported by the National Natural Science Foundation of China(52204255,22301267)Jiangsu Key Laboratory of Coal-based Greenhouse Gas Control and Utilization(PCSX202201)the Fundamental Research Funds for the Central Universities(JY220007)。
文摘Ligand-protected gold(Au_(n))clusters sometimes need the removal of organic ligands to expose more active sites and reduce steric hindrance in catalytic reactions,and large amount of organic and inorganic materials usually need to be employed as supports to anchor Aun clusters through different interaction mechanisms.Whereas,less comprehensive summaries have been provided about the crucial contribution of various supports to the catalytic performance of the supported Aun clusters.Herein,this review firstly summarizes synthesis methods(e.g.,impregnation and encapsulation processes)for the supported Aun cluster catalysts,and then mainly points out specific contributions of support effect in a great diversity of catalytic reactions,as well as deep interaction mechanisms.Besides,opportunities and challenging issues will be stated towards supported Aun clusters,in terms of improving catalytic performance and structural stability of Aun clusters inthedemand of catalysis.
基金support from European Union Seventh Frame-work Programme(FP7/2007-2013 project SusFuelCat,grant No.310490)is acknowledged.
文摘Aqueous-phase reforming(APR)is an attractive process to produce bio-based hydrogen from waste biomass streams,during which the catalyst stability is often challenged due to the harsh reaction conditions.In this work,three Pt-based catalysts supported on C,AlO(OH),and ZrO_(2)were investigated for the APR of hydroxyacetone solution in afixed bed reactor at 225℃and 35 bar.Among them,the Pt/C catalyst showed the highest turnover frequency for H_(2)production(TOF of 8.9 molH_(2)molPt^(-1)min^(-1))and the longest catalyst stability.Over the AlO(OH)and ZrO_(2)supported Pt catalysts,the side reactions consuming H_(2),formation of coke,and Pt sintering result in a low H_(2)production and the fast catalyst deactivation.The proposed reaction pathways suggest that a promising APR catalyst should reform all oxygenates in the aqueous phase,minimize the hydrogenation of the oxygenates,maximize the WGS reaction,and inhibit the condensation and coking reactions for maximizing the hydrogen yield and a stable catalytic performance.
基金Open Project of Yunnan Precious Metals Laboratory Co.,Ltd(YPML-2023050269)the Fundamental Research Funds for the Central Universities(226-2023-00085,226-2023-00057).
文摘Gold catalysts supported on Mg-Al mixed oxides for oxidative esterification of methacrolein are prepared by impregnation.Effects of the support particle size,concentration of HAuCl4 solution and Mg/Al ratio on gold loading and catalytic properties are investigated.The catalysts are characterized by CO_(2)-TPD,EDS,XPS,STEM and XRD techniques.Catalysts with smaller support particle size show more uniform gold distribution and higher gold dispersion,resulting in a higher catalytic performance,and the uniformity of gold and the activity of the catalysts with larger support particle size can be improved by decreasing the concentration of HAuCl4 solution.The Mg/Al molar ratio has significant effect on the uniformity of gold and the activity of the catalyst,and the optimum Mg/Al molar ratio is 0.1–0.2.This study underlines the importance of engineering support particle size,concentration of HAuCl4 solution and density of adsorption sites for efficient gold loading on support by impregnation.
文摘Recently,the arguments raised by Gang and Jing have been published in Chinese Journal of Integrative Medicine,(1)concerning the randomized controlled trial(RCT)of our team published in JAMA.(2)The conclusions of Gang and Jing(1)result not only from misunderstanding of the aims of our study,(2)but also a lack of basic knowledge for the design of RCT and the limitations on the content,and hence the length,of the primary outcome article in high-impact journals(i.e.2。
基金Projects 2006CB202200 supported by the National Basic Research Program of ChinaNCET07-0800 by the Program for New Century Excellent Talents in Universities
文摘The mechanical effects of bolt-mesh-anchor coupling support in deep tunnels were studied by using a numerical method, based on deep tunnel coupling supporting techniques and non-linear deformation mechanical theory of rock mass at great depths.It is shown that the potential of a rigid bolt support can be efficiently activated through the coupling effect between a bolt-net support and the surrounding rock.It is found that the accumulated plastic energy in the surrounding rock can be sufficiently transformed by the coupling effect of a bolt-mesh-tray support.The strength of the surrounding rock mass can be mobilized to control the deforma-tion of the surrounding rock by a pre-stress and time-space effect of the anchor support.The high stress transformation effect can be realized by the mechanical coupling effect of the bolt-mesh-anchor support, whereby the force of the support and deformation of the surrounding rock tends to become uniform, leading to a sustained stability of the tunnel.
基金supported by the National Natural Science Foundation of China (20873109)National Basic Research Program of China (973 program) (2005CB221401, 2010CB732303)+2 种基金Major Project of Chinese Minis-try of Education (309019)the PhD Programs Foundation of Chinese Ministry of Education (200803841011)Natural Science Foundation of Fujian Province, China (2008J0168)
文摘Supporting Pd catalysts characterized significant different size distribution were obtained using PdCl2,[Pd(NH3)4](NO3)2 and Pd(acac)2 as precursors.High-resolution transmission electron microscopy(TEM),X-ray diffraction(XRD),in-situ Fourier transform infrared spectroscopy(FTIR) and Raman spectroscopy were used to examine the dispersion of Pd.Catalytic performance measurements show that the activities for CO oxidation increase as the Pd particle size decreases and the O2/CO ratio increases.The activities under oxygen rich conditions are significantly higher than those at near the stoichiometric conditions.Pd on TiO2 prepared by the Pd(acac)2 precursor is highly dispersed,leading to a considerable activity for CO oxidation at near room temperature.CO oxidation on the 1 wt% Pd/TiO2 and under an O2/CO ratio of 1 characterized an apparent activation energy of 36.7 kJ/mol,which is closed to those reported for CO oxidation on the supported Au catalysts.The present work demonstrates a high catalytic activity of highly dispersed noble metals,and suggests a promising approach of using noble metals as catalysts with exceeding high efficiency.
文摘Achieving effective interaction can the students get good learning results,and enhance the quality of distance learning.The paper firstly analyzes the research on distance learning support services and the problems of distance learning interaction in order to clarify the significance of implementing effective interaction.Then it puts forward the learning support services strategies based on effective interaction,which means to promote distance learning interaction and enhance the students'self-learning ability.
基金financially supported by the National Natural Science Foundation of China(No.21276086)
文摘The effect of mixed oxide support on the performance of Ni/ZnO in the reactive adsorption desulfurization(RADS) reaction was investigated in a fixed bed reactor by using thiophene as the sulfur-containing compound in the model gasoline. A series of oxide supports for Ni/ZnO were synthesized by the co-precipitation method and characterized by XRD, N_2-adsorption, TPR and NH_3-TPD techniques. It was found that the desulfurization capacity of Ni/ZnO was enhanced greatly when active components were supported on the proper mixed oxide. Ni/ZnO supported on oxides exhibited much higher desulfurization efficiency and sulfur adsorption capacity than the unsupported Ni/ZnO and the synthesized Ni/ZnO-SA adsorbent exhibited the highest efficiency for thiophene removal. The higher desulfurization activity and sulfur capacity of Ni/ZnO supported on SiO_2-Al_2O_3 with small particle size, high specific surface area and large pore volume could promote the high dispersion of active metal phase and the transfer of sulfur to ZnO with lower mass transfer resistance. γ-Al_2O_3 species could weaken the interaction of active phases and SiO_2 as well as could increase greatly the amount of weak acids. Therefore, these oxides could impose a great influence on the structure and chemical properties of the catalyst.
基金Supported by the National Natural Science Foundation of China(No.20673068)
文摘Graphite intercalation compounds(GIC) were tested as an experimental model for studying the electronic effect of carbon support on the catalytic activity and poisoning tolerance of Pt catalyst for direct methanol fuel cells. The GIC samples with different intercalation degrees were prepared by electrolyzing graphite flake in H2SO4 for varying the periods of time. The GIC-supported Pt catalyst was deposited electrochemically. The catalytic activity and poisoning tolerance of the GIC-supported Pt catalysts were evaluated. It was found that GIC with sulfate anion as intercalate was able to catalyze methanol electrooxidation, which could be related to the positive charges generated on the graphite layer upon intercalation. As intercalation degree increased, the catalytic activity of the GIC-supported Pt catalyst decreased while the poisoning tolerance improved. This suggests that electron donation from support to catalyst had great effect on both catalytic activity and poisoning tolerance of Pt catalyst. And intercalation can be adopted as another important way to make modification on carboneous catalyst support.
文摘The paper firstly analyzes the problems of distance learning interaction in order to clarify the significance of implementing effective interaction.Then it puts forward the learning support services strategies based on effective interaction,which means to design strategies from the perspective of effective interaction to improve the effect of distance learning.
文摘The ditheion coefficients(Dapp) and the heterogeneous electron-transfer rate constan(ks)for ferrocene in MPEG/salt electrolytes were determined by using Steady-stae voltammetry. The temperature dependence of the two parameters obeys the Arrhenius equstion. The effect of the ionic size of sir supporting electrolytes on diffusion and electron transfer dynamics of fermcene was
文摘Objective:This study aimed to identify the mediation effects of health locus of control(HLC)and hope between stroke patients’social support and self-management.Methods:A cross-sectional study was conducted.A total of 300 Chinese stroke patients were recruited by convenient sampling from the acupuncture department of two Chinese Traditional Medical Hospitals in Tianjin Province from June to September 2018.The self-report questionnaires include Social Support Assessment Scale,Herth Hope Index,Mental Health Locus of Control Scale,Stroke Self-management Behavior Scale,and personal information questionnaires.All the survey data were entered in Excel and analyzed using the SPSS 24.0 program.Mediation was tested with Bootstrapping in AMOS 23.0 program.Results:The result showed that internal health locus of control(IHLC),chance health locus of control(CHLC)and hope were the mediators between social support and self-management.The direct,indirect,and total effects of social support on self-management behavior were 0.306 (P<0.01),0.109(P<0.01),and 0.415(P<0.01),respectively.Conclusions:Social support can directly influence self-management,and it can also indirectly influence self-management through IHLC,CHLC,and hope.