Under the backdrop of“Carbon Peak and Carbon Neutrality”(dual carbon)goal in China,the methane-carbon dioxide reforming reaction has attracted considerable attention due to its environmental benefits of converting t...Under the backdrop of“Carbon Peak and Carbon Neutrality”(dual carbon)goal in China,the methane-carbon dioxide reforming reaction has attracted considerable attention due to its environmental benefits of converting two greenhouse gases(methane and carbon dioxide)into syngas and its promising industrial applications.Nickel(Ni)-based catalysts,with high catalytic activity,low cost,and abundant resources,are considered ideal candidates for industrial applications.In this article,three reaction kinetic models were briefly introduced,namely the Power-Law(PL)model,the Eley-Rideal(ER)model,and the Langmuir-Hinshelwood-Hougen-Watson(LHHW)model.Based on the LHHW model,the reaction kinetics and mechanisms of different catalytic systems were systematically discussed,including the properties of supports,the doping of noble metals and transition metals,the role of promoters,and the influence of the geometric and electronic structures of Ni on the reaction mechanism.Furthermore,the kinetics of carbon deposition and elimination on various catalysts were analyzed.Based on the reaction rate expressions for carbon elimination,the reasons for the high activity of transition metal iron(Fe)-doped catalysts and core-shell structured catalysts in carbon elimination were explained.Based on the detailed collation and comparative analysis of the reaction mechanisms and kinetic characteristics across diverse Ni-based catalytic systems,a theoretical guidance for the designing of high-performance catalysts was provided in this work.展开更多
With ongoing global warming and increasing energy demands,the CH_(4)-CO_(2)reforming reaction(dry reforming of methane,DRM)has garnered significant attention as a promising carbon capture and utilization technology.Ni...With ongoing global warming and increasing energy demands,the CH_(4)-CO_(2)reforming reaction(dry reforming of methane,DRM)has garnered significant attention as a promising carbon capture and utilization technology.Nickel-based catalysts are renowned for their outstanding activity and selectivity in this process.The impact of metal-support interaction(MSI),on Ni-based catalyst performance has been extensively researched and debated recently.This paper reviews the recent research progress of MSI on Ni-based catalysts and their characterization and modulation strategies in catalytic reactions.From the perspective of MSI,the effects of different carriers(metal oxides,carbon materials and molecular sieves,etc.)are introduced on the dispersion and surface structure of Ni active metal particles,and the effect of MSI on the activity and stability of DRM reactions on Ni-based catalysts is discussed in detail.Future research should focus on better understanding and controlling MSI to improve the performance and durability of nickel-based catalysts in CH_(4)-CO_(2)reforming,advancing cleaner energy technologies.展开更多
CeO_(2) based semiconductor are widely used in solar-driven photothermal catalytic dry reforming of methane(DRM)reaction,but still suffer from low activity and low light utilization efficiency.This study developed gra...CeO_(2) based semiconductor are widely used in solar-driven photothermal catalytic dry reforming of methane(DRM)reaction,but still suffer from low activity and low light utilization efficiency.This study developed graphite-CeO_(2) interfaces to enhance solar-driven photothermal catalytic DRM.Compared with carbon nanotubes-modified CeO_(2)(CeO_(2)-CNT),graphite-modified CeO_(2)(CeO_(2)-GRA)constructed graphite-CeO_(2) interfaces with distortion in CeO_(2),leading to the formation abundant oxygen vacancies.These graphite-CeO_(2) interfaces with oxygen vacancies enhanced optical absorption and promoted the generation and separation of photogenerated carriers.The high endothermic capacity of graphite elevated the catalyst surface temperature from 592.1−691.3℃,boosting light-to-thermal conversion.The synergy between photogenerated carriers and localized heat enabled Ni/CeO_(2)-GRA to achieve a CO production rate of 9985.6 mmol/(g·h)(vs 7192.4 mmol/(g·h)for Ni/CeO_(2))and a light-to-fuel efficiency of 21.8%(vs 13.8%for Ni/CeO_(2)).This work provides insights for designing graphite-semiconductor interfaces to advance photothermal catalytic efficiency.展开更多
This study explores the controllable synthesis of CuAlO_(2) using copper hydroxide and pseudo-boehmite powders as raw materials via a simple solid-phase ball milling method,along with its catalytic performance investi...This study explores the controllable synthesis of CuAlO_(2) using copper hydroxide and pseudo-boehmite powders as raw materials via a simple solid-phase ball milling method,along with its catalytic performance investigation in methanol steam reforming(MSR).Various catalysts were prepared under different conditions,such as calcination temperature,calcination atmosphere,and heating rate.Characterization techniques including BET,XRD,XPS,SEM and H2-TPR were employed to analyze the samples.The results revealed significant effects of calcination temperature on the phase compositions,specific surface area,reduction performance,and surface properties of the CA-T catalysts.Based on the findings,a synthesis route of CuAlO_(2) via the solid-phase method was proposed,highlighting the importance of high calcination temperature,nitrogen atmosphere,and low heating rate for CuAlO_(2) formation.Catalytic evaluation data demonstrated that CuAlO_(2) could catalyze MSR without pre-reduction,with the catalytic performance of CA-T catalysts being notably influenced by calcination temperature.Among the prepared catalysts,the CA-1100 catalyst exhibited the highest catalytic activity and stability.The findings of this study might be useful for the further study of the catalytic material for sustained release catalysis,including the synthesis of catalytic materials and the regulation of sustained release catalytic performance.展开更多
Perovskites as host structures of cations were used in order to generate in situ active and stable catalysts for ethanol steam reforming. For this purpose,La_(1-x)Mg_xAl_(1-y)Ni_yO_3(x = 0.1; y = 0,0.1,0.2,0.3) perovs...Perovskites as host structures of cations were used in order to generate in situ active and stable catalysts for ethanol steam reforming. For this purpose,La_(1-x)Mg_xAl_(1-y)Ni_yO_3(x = 0.1; y = 0,0.1,0.2,0.3) perovskites were synthetized by the citrate method.Ni segregation is evident for a substitution level higher than 0. 2. The segregation of Ni as NiO generated species interacts with different metal-support after the reduction step. The y = 0.1 catalyst presents the highest H_2 yield value about 85% during reaction time,with low mean values of CH_4 and CO selectivities of 3.4% and 11%,respectively and a low carbon formation. The better performance of y = 0.1 catalyst could be attributed to the minor proportion of segregated phases,thus a controlled expulsion of Ni is successfully reached.展开更多
Steam reforming of methanol was carried out on the copper-silica aerogel catalyst.The effects of reaction temperature,feed rate,water to methanol molar ratio and carrier gas flowrate on the H_2 production rate and CO ...Steam reforming of methanol was carried out on the copper-silica aerogel catalyst.The effects of reaction temperature,feed rate,water to methanol molar ratio and carrier gas flowrate on the H_2 production rate and CO selectivity were investigated.M ethanol conversion was increased considerably in the range of about 240-300,after which it increased at a slightly lower rate.The used feed flowrate,steam to methanol molar ratio and carrier gas flowwere 1.2-9.0 m L/h,1.2-5.0 and 20-80 m L/min,respectively.Reducing the feed flowrate increased the H_2 production rate.It was found that an increase in the water to methanol ratio and decreasing the carrier gas flowrate slightly increases the H2production rate.Increasing the water to methanol ratio causes the lowest temperature in which CO formation was observed to rise,so that for the ratio of 5.0 no CO formation was detected in temperatures lower than 375℃.In all conditions,by approaching the complete conversion,increasing the main product concentration,increasing the temperature and contact time,and decreasing the steam to methanol ratio,the CO selectivity was increased.These results suggested that CO was formed as a secondary product through reverse water-gas shift reaction and did not participate in the methanol steam reforming reaction mechanism.展开更多
Ni/TiO_(2) catalyst is widely employed for photo-driven DRM reaction while the influence of crystal structure of TiO_(2) remains unclear.In this work,the rutile/anatase ratio in supports was successfully controlled by...Ni/TiO_(2) catalyst is widely employed for photo-driven DRM reaction while the influence of crystal structure of TiO_(2) remains unclear.In this work,the rutile/anatase ratio in supports was successfully controlled by varying the calcination temperature of anatase-TiO_(2).Structural characterizations revealed that a distinct TiO_(x) coating on the Ni nanoparticles(NPs)was evident for Ni/TiO_(2)-700 catalyst due to strong metal-support interaction.It is observed that the TiOx overlayer gradually disappeared as the ratio of rutile/anatase increased,thereby enhancing the exposure of Ni active sites.The exposed Ni sites enhanced visible light absorption and boosted the dissociation capability of CH4,which led to the much elevated catalytic activity for Ni/TiO_(2)-950 in which rutile dominated.Therefore,the catalytic activity of solar-driven DRM reaction was significantly influenced by the rutile/anatase ratio.Ni/TiO_(2)-950,characterized by a predominant rutile phase,exhibited the highest DRM reactivity,with remarkable H_(2) and CO production rates reaching as high as 87.4 and 220.2 mmol/(g·h),respectively.These rates were approximately 257 and 130 times higher,respectively,compared to those obtained on Ni/TiO_(2)-700 with anatase.This study suggests that the optimization of crystal structure of TiO_(2) support can effectively enhance the performance of photothermal DRM reaction.展开更多
Roof disaster has always been an important factor restricting coal mine safety production.Acidic effect can reform the rock mass structure to weaken the macroscopic strength characteristics,which is an effective way t...Roof disaster has always been an important factor restricting coal mine safety production.Acidic effect can reform the rock mass structure to weaken the macroscopic strength characteristics,which is an effective way to control the hard limestone roof.In this study,the effects of various factors on the reaction characteristics and mechanical properties of limestone were analyzed.The results show that the acid with stronger hydrogen production capacity after ionization(pK_(a)<0)has more prominent damage to the mineral grains of limestone.When pKa increases from−8.00 to 15.70,uniaxial compressive strength and elastic modulus of limestone increase by 117.22%and 75.98%.The influence of acid concentration is manifested in the dissolution behavior of mineral crystals,the crystal defects caused by large-scale acid action will lead to the deterioration of limestone strength,and the strength after 15%concentration reformation can be reduced by 59.42%.The effect of acidification time on limestone has stages and is the most obvious in the initial metathesis reaction stage(within 60 min).The key to the strength damage of acidified limestone is the participation of hydrogen ions in the reaction system.Based on the analytic hierarchy process method,the influence weights of acid type,acid concentration and acidification time on strength are 24.30%,59.54% and 16.16%,respectively.The research results provide theoretical support for the acidification control of hard limestone roofs in coal mines.展开更多
In this paper, we present a real decision support system applied to China's macroeconomic management. The structure, design and functions of the system are discussed, and the problems occurring in designing and ma...In this paper, we present a real decision support system applied to China's macroeconomic management. The structure, design and functions of the system are discussed, and the problems occurring in designing and making the system are also studied. A case study for China's petroleum price reform is given at the end of the paper.展开更多
The social and economic development level of rural areas, the productivity of agriculture and the life quality of farmers were always the greatest concerns of Chinese Central Government. Therefore, the research relate...The social and economic development level of rural areas, the productivity of agriculture and the life quality of farmers were always the greatest concerns of Chinese Central Government. Therefore, the research related to rural areas, agriculture and farmers had remained as the prominent parts for a long period and would continue to be prominent in the future to build China into a moderately prosperous nation in an all-round way. Chinese rural area had constantly experienced three significant system reforms since 1978, namely the reform of rural management system, the rural tax and fee reform and the rural comprehensive reform. This paper attempted to analyze the theoretic framework and the content structure of the comprehensive rural reform since it was the higher stage of rural institutional vicissitude, which had changed the governance and operation system and thus promoted the great changes to fundamental social and economic system in rural areas. The theoretic framework of comprehensive rural reform covered three aspects in its content, namely the rural governance theory, the government function theory and the public finance theory. The comprehensive rural reform was a complicated system engineering with multiple dimensions and targets mainly including rural political restructuring, rural economic restructuring and rural public products allocation restructuring. The reform had focused on enhancing the vitality of agricultural and rural development, breaking through the urban and rural binary system, and further reducing the disparity between cities and countrysides, so as to realize the urban-rural integration. It was necessary to clarify and understand the key mechanism and intrinsic logic of the rural comprehensive reform, which was helpful to establish the foundation constituted by scientific methodology to implement the reform and evaluation criterion to judge the reform performance.展开更多
The changing of flow conditions caused by construction of hydro-projects will result in river's refor-mation and development of channel pattern.In this paper,the development of channel pattem in the process ofrefo...The changing of flow conditions caused by construction of hydro-projects will result in river's refor-mation and development of channel pattern.In this paper,the development of channel pattem in the process ofreformation is studied by means of flume experiments.Influence of slope,grain size,angle-of-inflow,dis-charge and discharge process are comprehensively analyzed according to the experimental data.It was foundthat the channel would be widened as the river slope or discharge increased and grain size decreased.If theangle-of-inflow was not zero,under certain conditions of grain size and discharge,a most suitable slope exist-ed,for which the river would develop into a pattem of meandering.Different discharge process would imposeon the change of river morphology,even caused transformation of channel patterns.Diversity in the capacity ofshaping rivers of different discharges especially the flood duration cast a light on the change of channel pattern.展开更多
As a systematic project, Chinese rural comprehensive reform （hereinafter referred to as ＂the reform＂） involved multiple dimensions such as rural governance, economy, culture, society and ecology, which laid a soli...As a systematic project, Chinese rural comprehensive reform （hereinafter referred to as ＂the reform＂） involved multiple dimensions such as rural governance, economy, culture, society and ecology, which laid a solid foundation for the overall reform in China. Western rural development theory had been proved to be insufficient to support Chinese rural reform. Therefore, theoretical innovation became urgent in the fields of rural governance, government functions, public finance and rural-urban integration etc. In recent years, Chinese rural comprehensive reform had been adjusting itself to the requirements of the ＂new normal＂. And during the process of agricultural modernization, the bottlenecks included the contradictory relationships between reform, development and overall stability, agricultural simplification and industrial diversification, economic development and environmental protection, rapid development of urban areas and slow progress of rural areas, grassroots governance and democratic supervision etc. Proper countermeasures would help to settle the above contradictions.展开更多
Coal pyrolysis integrated with dry reforming of low-carbon alkane(CP-DRA)is an effective way to improve tar yield.Ni/La_(2)O_(3)-ZrO_(2) with a La/Zr ratio of 4 was a good catalyst for DRA to inhibit carbon deposition...Coal pyrolysis integrated with dry reforming of low-carbon alkane(CP-DRA)is an effective way to improve tar yield.Ni/La_(2)O_(3)-ZrO_(2) with a La/Zr ratio of 4 was a good catalyst for DRA to inhibit carbon deposition and obtain high tar yield in CP-DRA.In this study,the fraction distribution and component of tars from CP-DRA and coal pyrolysis in N_(2) atmosphere(CP-N_(2))were characterized by using several methods to understand the effect of DRA on coal pyrolysis.The isotope trace method was also used to discuss the role of low-carbon alkane in CP-DRA.The results showed that the tar from CP-N_(2)is mainly composed of aliphatic compounds with more C_(al),H_(al) and CH+CH_(2),and the tar from CP-DRA contains more Car,Har,and CH_(3),and has lower weight-average molecular weight and more light tar content than CP-N_(2).A small amount of C_(2)H_(6) addition in CP-DRA will raise the ratio of H_(β) and CH+CH_(2).Electron paramagnetic resonance(EPR)analysis shows that the tar from CP-DRA has a higher radical concentration while the corresponding char has a lower radical concentration.The isotope trace experiment showed that alkanes provide·H,·CH_(3),etc.to stabilize the radicals from coal pyrolysis and result in more alkyl aromatic compounds during CP-DRA.展开更多
India's economic reform started from the realm of finance, which is within the category of soft power of a country. The wax and wane of the overall power of a country is largely determined by the interplay of hard...India's economic reform started from the realm of finance, which is within the category of soft power of a country. The wax and wane of the overall power of a country is largely determined by the interplay of hard and soft pwers in question. India's soft power has its own characteristics and advantages, which chiefly manifest in its culture, parliamentary democracy, education and finance. In the 21st century, these advantages will continue to have significant play.展开更多
In the current study simultaneous reactions of hydrodesulfurization(HDS) of dibenzothiophene(DBT) and reforming of methanol in a micro-autoclave reactor were studied over bi-metallic(Co-Mo/Al2O3 and Ni-Mo/Al2O3) and t...In the current study simultaneous reactions of hydrodesulfurization(HDS) of dibenzothiophene(DBT) and reforming of methanol in a micro-autoclave reactor were studied over bi-metallic(Co-Mo/Al2O3 and Ni-Mo/Al2O3) and tri-metallic(Pd-Co-Mo/Al2O3 and Pd-Ni-Mo/Al2O3) catalyst systems which were prepared by incipient impregnation method.In situ hydrogen utilization and low Pd loadings were the major targets of this study.For comparison purpose,catalytic activity was separately determined for both the methanol reforming and HDS of DBT reactions as well.Ni based catalysts were confirmed with better activity than Co ones for both the reactions with Pd promoted ones ranking at the top i.e.Pd-Ni-Mo/Al2O3 > Ni-Mo/Al2O3 > Pd-Co-Mo/Al2O3 > Co-Mo/Al2O3 where Pd-Ni-Mo/Al2O3 showed 91% DBT conversion at 380 ℃ and 12 h reaction time.Some of the selected organic additives on catalytic activity were tested for their effect toward HDS reaction which was unique with close relation to their chemical nature.Reaction products were quantitatively and qualitatively analyzed via HPLC and GC-MS techniques respectively which helped in elucidating reaction mechanism.展开更多
The effect of oxidation pretreatment temperature(500 ~ 1 000 ℃) on the catalytic activity of Kovar applied on hydrocarbon CO2reforming was examined. Catalytic performance evaluation using tetradecane at 800 ℃ with ...The effect of oxidation pretreatment temperature(500 ~ 1 000 ℃) on the catalytic activity of Kovar applied on hydrocarbon CO2reforming was examined. Catalytic performance evaluation using tetradecane at 800 ℃ with 70 μmol/s CO2revealed 700 and 1 000 ℃ as the best pre-oxidation temperature in producing CO and H2,respectively. XRD and SEM-EDX analyses showed that a separate metal oxide layer composed of iron oxide(Fe2O3and F3O4),nickel,cobalt,and possibly their respective oxides started to form when oxidation was conducted at 700 ℃ or higher.The presence of iron enhanced the stability of nickel in the structure while the compact structure of Fe3O4resulted into the formation of a thick and rigid metal oxide layer on the surface of the Kovar tube. The strong physical bond between the metal oxide layer and Kovar tube provided the catalyst good mechanical strength and consequently good catalytic activity.展开更多
With the accelerated reform of the state-owned industry,deregulation and competition continues,but integrated layout and regulation reconstruction are more and more expected.Through analyzing power,telecom,and tobacco...With the accelerated reform of the state-owned industry,deregulation and competition continues,but integrated layout and regulation reconstruction are more and more expected.Through analyzing power,telecom,and tobacco industry’s reform model,this paper advances a general model of deepening monopoly reform,which applies regulation reconstruction to industry restricting and monitoring regulation improvement,promoting the harmonious development of the central and local industries and promoting the vitality,influence,control force as well as anti-risk capability of the state-owned economy comprehensively.展开更多
基金Supported by Innovation Capability Support Program of Shaanxi(2024RS-CXTD-53,2024ZC-KJXX-096)the Key R&D Program of Shaanxi Province(2022QCY-LL-69)Xi’an Science and Technology Project(24GXFW0089)。
文摘Under the backdrop of“Carbon Peak and Carbon Neutrality”(dual carbon)goal in China,the methane-carbon dioxide reforming reaction has attracted considerable attention due to its environmental benefits of converting two greenhouse gases(methane and carbon dioxide)into syngas and its promising industrial applications.Nickel(Ni)-based catalysts,with high catalytic activity,low cost,and abundant resources,are considered ideal candidates for industrial applications.In this article,three reaction kinetic models were briefly introduced,namely the Power-Law(PL)model,the Eley-Rideal(ER)model,and the Langmuir-Hinshelwood-Hougen-Watson(LHHW)model.Based on the LHHW model,the reaction kinetics and mechanisms of different catalytic systems were systematically discussed,including the properties of supports,the doping of noble metals and transition metals,the role of promoters,and the influence of the geometric and electronic structures of Ni on the reaction mechanism.Furthermore,the kinetics of carbon deposition and elimination on various catalysts were analyzed.Based on the reaction rate expressions for carbon elimination,the reasons for the high activity of transition metal iron(Fe)-doped catalysts and core-shell structured catalysts in carbon elimination were explained.Based on the detailed collation and comparative analysis of the reaction mechanisms and kinetic characteristics across diverse Ni-based catalytic systems,a theoretical guidance for the designing of high-performance catalysts was provided in this work.
基金supported by the Natural Science Foundation of Shanxi Province(202203021221155)the Foundation of National Key Laboratory of High Efficiency and Low Carbon Utilization of Coal(J23-24-902)。
文摘With ongoing global warming and increasing energy demands,the CH_(4)-CO_(2)reforming reaction(dry reforming of methane,DRM)has garnered significant attention as a promising carbon capture and utilization technology.Nickel-based catalysts are renowned for their outstanding activity and selectivity in this process.The impact of metal-support interaction(MSI),on Ni-based catalyst performance has been extensively researched and debated recently.This paper reviews the recent research progress of MSI on Ni-based catalysts and their characterization and modulation strategies in catalytic reactions.From the perspective of MSI,the effects of different carriers(metal oxides,carbon materials and molecular sieves,etc.)are introduced on the dispersion and surface structure of Ni active metal particles,and the effect of MSI on the activity and stability of DRM reactions on Ni-based catalysts is discussed in detail.Future research should focus on better understanding and controlling MSI to improve the performance and durability of nickel-based catalysts in CH_(4)-CO_(2)reforming,advancing cleaner energy technologies.
文摘CeO_(2) based semiconductor are widely used in solar-driven photothermal catalytic dry reforming of methane(DRM)reaction,but still suffer from low activity and low light utilization efficiency.This study developed graphite-CeO_(2) interfaces to enhance solar-driven photothermal catalytic DRM.Compared with carbon nanotubes-modified CeO_(2)(CeO_(2)-CNT),graphite-modified CeO_(2)(CeO_(2)-GRA)constructed graphite-CeO_(2) interfaces with distortion in CeO_(2),leading to the formation abundant oxygen vacancies.These graphite-CeO_(2) interfaces with oxygen vacancies enhanced optical absorption and promoted the generation and separation of photogenerated carriers.The high endothermic capacity of graphite elevated the catalyst surface temperature from 592.1−691.3℃,boosting light-to-thermal conversion.The synergy between photogenerated carriers and localized heat enabled Ni/CeO_(2)-GRA to achieve a CO production rate of 9985.6 mmol/(g·h)(vs 7192.4 mmol/(g·h)for Ni/CeO_(2))and a light-to-fuel efficiency of 21.8%(vs 13.8%for Ni/CeO_(2)).This work provides insights for designing graphite-semiconductor interfaces to advance photothermal catalytic efficiency.
基金supported by the Scientific Research Foundation for High-level Talents of Anhui University of Science and Technology(2023yjrc51)the National Natural Science Foundation of China(22172184)+2 种基金the Foundation of State Key Laboratory of Coal Conversion(J24-25-603)the Fundamental Research Project of ICC-CAS(SCJC-DT-2023-01)Weiqiao-UCAS Special Projects on Low-Carbon Technology Development(GYY-DTFZ-2022-015)。
文摘This study explores the controllable synthesis of CuAlO_(2) using copper hydroxide and pseudo-boehmite powders as raw materials via a simple solid-phase ball milling method,along with its catalytic performance investigation in methanol steam reforming(MSR).Various catalysts were prepared under different conditions,such as calcination temperature,calcination atmosphere,and heating rate.Characterization techniques including BET,XRD,XPS,SEM and H2-TPR were employed to analyze the samples.The results revealed significant effects of calcination temperature on the phase compositions,specific surface area,reduction performance,and surface properties of the CA-T catalysts.Based on the findings,a synthesis route of CuAlO_(2) via the solid-phase method was proposed,highlighting the importance of high calcination temperature,nitrogen atmosphere,and low heating rate for CuAlO_(2) formation.Catalytic evaluation data demonstrated that CuAlO_(2) could catalyze MSR without pre-reduction,with the catalytic performance of CA-T catalysts being notably influenced by calcination temperature.Among the prepared catalysts,the CA-1100 catalyst exhibited the highest catalytic activity and stability.The findings of this study might be useful for the further study of the catalytic material for sustained release catalysis,including the synthesis of catalytic materials and the regulation of sustained release catalytic performance.
文摘Perovskites as host structures of cations were used in order to generate in situ active and stable catalysts for ethanol steam reforming. For this purpose,La_(1-x)Mg_xAl_(1-y)Ni_yO_3(x = 0.1; y = 0,0.1,0.2,0.3) perovskites were synthetized by the citrate method.Ni segregation is evident for a substitution level higher than 0. 2. The segregation of Ni as NiO generated species interacts with different metal-support after the reduction step. The y = 0.1 catalyst presents the highest H_2 yield value about 85% during reaction time,with low mean values of CH_4 and CO selectivities of 3.4% and 11%,respectively and a low carbon formation. The better performance of y = 0.1 catalyst could be attributed to the minor proportion of segregated phases,thus a controlled expulsion of Ni is successfully reached.
文摘Steam reforming of methanol was carried out on the copper-silica aerogel catalyst.The effects of reaction temperature,feed rate,water to methanol molar ratio and carrier gas flowrate on the H_2 production rate and CO selectivity were investigated.M ethanol conversion was increased considerably in the range of about 240-300,after which it increased at a slightly lower rate.The used feed flowrate,steam to methanol molar ratio and carrier gas flowwere 1.2-9.0 m L/h,1.2-5.0 and 20-80 m L/min,respectively.Reducing the feed flowrate increased the H_2 production rate.It was found that an increase in the water to methanol ratio and decreasing the carrier gas flowrate slightly increases the H2production rate.Increasing the water to methanol ratio causes the lowest temperature in which CO formation was observed to rise,so that for the ratio of 5.0 no CO formation was detected in temperatures lower than 375℃.In all conditions,by approaching the complete conversion,increasing the main product concentration,increasing the temperature and contact time,and decreasing the steam to methanol ratio,the CO selectivity was increased.These results suggested that CO was formed as a secondary product through reverse water-gas shift reaction and did not participate in the methanol steam reforming reaction mechanism.
基金The project was supported by the National Key R&D Program of China(2021YFF0500702)Natural Science Foundation of Shanghai(22JC1404200)+3 种基金Program of Shanghai Academic/Technology Research Leader(20XD1404000)Natural Science Foundation of China(U22B20136,22293023)Science and Technology Major Project of Inner Mongolia(2021ZD0042)the Youth Innovation Promotion Association of CAS。
文摘Ni/TiO_(2) catalyst is widely employed for photo-driven DRM reaction while the influence of crystal structure of TiO_(2) remains unclear.In this work,the rutile/anatase ratio in supports was successfully controlled by varying the calcination temperature of anatase-TiO_(2).Structural characterizations revealed that a distinct TiO_(x) coating on the Ni nanoparticles(NPs)was evident for Ni/TiO_(2)-700 catalyst due to strong metal-support interaction.It is observed that the TiOx overlayer gradually disappeared as the ratio of rutile/anatase increased,thereby enhancing the exposure of Ni active sites.The exposed Ni sites enhanced visible light absorption and boosted the dissociation capability of CH4,which led to the much elevated catalytic activity for Ni/TiO_(2)-950 in which rutile dominated.Therefore,the catalytic activity of solar-driven DRM reaction was significantly influenced by the rutile/anatase ratio.Ni/TiO_(2)-950,characterized by a predominant rutile phase,exhibited the highest DRM reactivity,with remarkable H_(2) and CO production rates reaching as high as 87.4 and 220.2 mmol/(g·h),respectively.These rates were approximately 257 and 130 times higher,respectively,compared to those obtained on Ni/TiO_(2)-700 with anatase.This study suggests that the optimization of crystal structure of TiO_(2) support can effectively enhance the performance of photothermal DRM reaction.
基金Project(2021YFC2902102)supported by the National Key Research and Development Program of ChinaProject(52374142)supported by the National Natural Science Foundation of ChinaProject(JSTU-2022-066)supported by the Young Talent Support Project of Jiangsu Association for Science and Technology,China。
文摘Roof disaster has always been an important factor restricting coal mine safety production.Acidic effect can reform the rock mass structure to weaken the macroscopic strength characteristics,which is an effective way to control the hard limestone roof.In this study,the effects of various factors on the reaction characteristics and mechanical properties of limestone were analyzed.The results show that the acid with stronger hydrogen production capacity after ionization(pK_(a)<0)has more prominent damage to the mineral grains of limestone.When pKa increases from−8.00 to 15.70,uniaxial compressive strength and elastic modulus of limestone increase by 117.22%and 75.98%.The influence of acid concentration is manifested in the dissolution behavior of mineral crystals,the crystal defects caused by large-scale acid action will lead to the deterioration of limestone strength,and the strength after 15%concentration reformation can be reduced by 59.42%.The effect of acidification time on limestone has stages and is the most obvious in the initial metathesis reaction stage(within 60 min).The key to the strength damage of acidified limestone is the participation of hydrogen ions in the reaction system.Based on the analytic hierarchy process method,the influence weights of acid type,acid concentration and acidification time on strength are 24.30%,59.54% and 16.16%,respectively.The research results provide theoretical support for the acidification control of hard limestone roofs in coal mines.
基金This Project is partly supported by World Bank and National Science Foundation of China.And this is a team work,Prof. Deng Shuhui and Dr.Wu jianzhong also play an important role in the project
文摘In this paper, we present a real decision support system applied to China's macroeconomic management. The structure, design and functions of the system are discussed, and the problems occurring in designing and making the system are also studied. A case study for China's petroleum price reform is given at the end of the paper.
基金Supported by the Funding from the Doctoral Research Foundation of Zhaoqing University(2013)
文摘The social and economic development level of rural areas, the productivity of agriculture and the life quality of farmers were always the greatest concerns of Chinese Central Government. Therefore, the research related to rural areas, agriculture and farmers had remained as the prominent parts for a long period and would continue to be prominent in the future to build China into a moderately prosperous nation in an all-round way. Chinese rural area had constantly experienced three significant system reforms since 1978, namely the reform of rural management system, the rural tax and fee reform and the rural comprehensive reform. This paper attempted to analyze the theoretic framework and the content structure of the comprehensive rural reform since it was the higher stage of rural institutional vicissitude, which had changed the governance and operation system and thus promoted the great changes to fundamental social and economic system in rural areas. The theoretic framework of comprehensive rural reform covered three aspects in its content, namely the rural governance theory, the government function theory and the public finance theory. The comprehensive rural reform was a complicated system engineering with multiple dimensions and targets mainly including rural political restructuring, rural economic restructuring and rural public products allocation restructuring. The reform had focused on enhancing the vitality of agricultural and rural development, breaking through the urban and rural binary system, and further reducing the disparity between cities and countrysides, so as to realize the urban-rural integration. It was necessary to clarify and understand the key mechanism and intrinsic logic of the rural comprehensive reform, which was helpful to establish the foundation constituted by scientific methodology to implement the reform and evaluation criterion to judge the reform performance.
基金Supported by National Key Basic Research and Development Program(973 Program)(2003CB415205)the National Natural Science Foundation of China(50479036)
文摘The changing of flow conditions caused by construction of hydro-projects will result in river's refor-mation and development of channel pattern.In this paper,the development of channel pattem in the process ofreformation is studied by means of flume experiments.Influence of slope,grain size,angle-of-inflow,dis-charge and discharge process are comprehensively analyzed according to the experimental data.It was foundthat the channel would be widened as the river slope or discharge increased and grain size decreased.If theangle-of-inflow was not zero,under certain conditions of grain size and discharge,a most suitable slope exist-ed,for which the river would develop into a pattem of meandering.Different discharge process would imposeon the change of river morphology,even caused transformation of channel patterns.Diversity in the capacity ofshaping rivers of different discharges especially the flood duration cast a light on the change of channel pattern.
基金Supported by the Funding from the Doctoral Research of Zhaoqing University(2013)
文摘As a systematic project, Chinese rural comprehensive reform （hereinafter referred to as ＂the reform＂） involved multiple dimensions such as rural governance, economy, culture, society and ecology, which laid a solid foundation for the overall reform in China. Western rural development theory had been proved to be insufficient to support Chinese rural reform. Therefore, theoretical innovation became urgent in the fields of rural governance, government functions, public finance and rural-urban integration etc. In recent years, Chinese rural comprehensive reform had been adjusting itself to the requirements of the ＂new normal＂. And during the process of agricultural modernization, the bottlenecks included the contradictory relationships between reform, development and overall stability, agricultural simplification and industrial diversification, economic development and environmental protection, rapid development of urban areas and slow progress of rural areas, grassroots governance and democratic supervision etc. Proper countermeasures would help to settle the above contradictions.
基金supported by the National Natural Science Foundation of China(21576046)the Innovation Team Support Program in Key Areas of the Dalian Science and Technology Bureau(2019RT10).
文摘Coal pyrolysis integrated with dry reforming of low-carbon alkane(CP-DRA)is an effective way to improve tar yield.Ni/La_(2)O_(3)-ZrO_(2) with a La/Zr ratio of 4 was a good catalyst for DRA to inhibit carbon deposition and obtain high tar yield in CP-DRA.In this study,the fraction distribution and component of tars from CP-DRA and coal pyrolysis in N_(2) atmosphere(CP-N_(2))were characterized by using several methods to understand the effect of DRA on coal pyrolysis.The isotope trace method was also used to discuss the role of low-carbon alkane in CP-DRA.The results showed that the tar from CP-N_(2)is mainly composed of aliphatic compounds with more C_(al),H_(al) and CH+CH_(2),and the tar from CP-DRA contains more Car,Har,and CH_(3),and has lower weight-average molecular weight and more light tar content than CP-N_(2).A small amount of C_(2)H_(6) addition in CP-DRA will raise the ratio of H_(β) and CH+CH_(2).Electron paramagnetic resonance(EPR)analysis shows that the tar from CP-DRA has a higher radical concentration while the corresponding char has a lower radical concentration.The isotope trace experiment showed that alkanes provide·H,·CH_(3),etc.to stabilize the radicals from coal pyrolysis and result in more alkyl aromatic compounds during CP-DRA.
文摘India's economic reform started from the realm of finance, which is within the category of soft power of a country. The wax and wane of the overall power of a country is largely determined by the interplay of hard and soft pwers in question. India's soft power has its own characteristics and advantages, which chiefly manifest in its culture, parliamentary democracy, education and finance. In the 21st century, these advantages will continue to have significant play.
基金Fundamental Research Foundation of Sinopec(X505015)
文摘In the current study simultaneous reactions of hydrodesulfurization(HDS) of dibenzothiophene(DBT) and reforming of methanol in a micro-autoclave reactor were studied over bi-metallic(Co-Mo/Al2O3 and Ni-Mo/Al2O3) and tri-metallic(Pd-Co-Mo/Al2O3 and Pd-Ni-Mo/Al2O3) catalyst systems which were prepared by incipient impregnation method.In situ hydrogen utilization and low Pd loadings were the major targets of this study.For comparison purpose,catalytic activity was separately determined for both the methanol reforming and HDS of DBT reactions as well.Ni based catalysts were confirmed with better activity than Co ones for both the reactions with Pd promoted ones ranking at the top i.e.Pd-Ni-Mo/Al2O3 > Ni-Mo/Al2O3 > Pd-Co-Mo/Al2O3 > Co-Mo/Al2O3 where Pd-Ni-Mo/Al2O3 showed 91% DBT conversion at 380 ℃ and 12 h reaction time.Some of the selected organic additives on catalytic activity were tested for their effect toward HDS reaction which was unique with close relation to their chemical nature.Reaction products were quantitatively and qualitatively analyzed via HPLC and GC-MS techniques respectively which helped in elucidating reaction mechanism.
基金Supported by a research grant(K2106)from the Ministry of Environment of Japan
文摘The effect of oxidation pretreatment temperature(500 ~ 1 000 ℃) on the catalytic activity of Kovar applied on hydrocarbon CO2reforming was examined. Catalytic performance evaluation using tetradecane at 800 ℃ with 70 μmol/s CO2revealed 700 and 1 000 ℃ as the best pre-oxidation temperature in producing CO and H2,respectively. XRD and SEM-EDX analyses showed that a separate metal oxide layer composed of iron oxide(Fe2O3and F3O4),nickel,cobalt,and possibly their respective oxides started to form when oxidation was conducted at 700 ℃ or higher.The presence of iron enhanced the stability of nickel in the structure while the compact structure of Fe3O4resulted into the formation of a thick and rigid metal oxide layer on the surface of the Kovar tube. The strong physical bond between the metal oxide layer and Kovar tube provided the catalyst good mechanical strength and consequently good catalytic activity.
基金the staged achievement of the key project of soft science of the Science and Technology Agency of Sichuan-On the Risk Identification and Risk Management System of the International Operation of China’s Petroleum Enterprises(2014ZR0075)
文摘With the accelerated reform of the state-owned industry,deregulation and competition continues,but integrated layout and regulation reconstruction are more and more expected.Through analyzing power,telecom,and tobacco industry’s reform model,this paper advances a general model of deepening monopoly reform,which applies regulation reconstruction to industry restricting and monitoring regulation improvement,promoting the harmonious development of the central and local industries and promoting the vitality,influence,control force as well as anti-risk capability of the state-owned economy comprehensively.
