检索结果-南通市图书馆

molybdenum carbide as catalyst in biomass derivatives conversion

Journal of Energy Chemistry 2022年第10期31卷 68-87,I0003页

作者： Xiangze Du Rui Zhang Dan Li Changwei Hu Hermenegildo Garcia Key Laboratory of Green Chemistry and Technology Ministry of EducationCollege of ChemistrySichuan UniversityChengdu 610064SichuanChina Instituto Universitario de Tecnología Química Consejo Superior de Investigaciones Científicas.-Universitat Politecnica de ValenciaUniversitat Politecnica de ValenciaAv.De los Naranjos s/nValencia 46022Spain Department of Chemistry University of HelsinkiA.I.Virtasen Aukio 1P.O.Box 5500014Finland

The present energy dilemma in conjunction with the adverse environmental impacts caused by fossil fuel combustion motivates researchers to seek for new renewable energy with minimal CO_(2)*** a practice pathway,it is of significance to produce biofuel and platform chemicals from sustainable biomass ***,the research and development of high-efficiency catalysts remain one key scientific *** the catalysts developed,transition metal carbides,especially molybdenum carbide,show promising performances on biomass-based *** efforts have been made in past few decades on tuning the structure and electronic property of molybdenum carbide via controlling particle size and morphology,metal and nonmetal doping and vacancies,*** review summarizes recent developments of molybdenum carbide as catalysts in converting biomass into fuel,mainly focused on the preparation methods,the structure-dependent effects and the electronic *** controllable selective cleavage of C-C,C-O and C-H bonds over modified molybdenum carbides that has been demonstrated in the conversion of biomass feedstocks is then *** addition,the possible deactivation mechanisms of molybdenum carbide are also presented in the *** review provides systematic and fundamental information for the further design and development of molybdenum carbide for the conversion of biomass resources.

关键词： molybdenum carbide Synthesis Modification Hydrogenation Biomass Selective cleavage

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Thermodynamic study and methanothermal temperature-programmed reaction synthesis of molybdenum carbide

引用

International Journal of Minerals,Metallurgy and Materials 2016年第3期23卷 339-347页

作者： Parham Roohi Reza Alizadeh Esmaeil Fatehifar Chemical Engineering Faculty Sahand University of Technology

Nanostructured molybdenum carbide （Mo2C） was successfully prepared from molybdenum trioxide （MoO3） using methanothermal temperature-programmed reaction. Thermodynamic analysis indicated that in presence of methane, the formation of Mo2C from MoO3 occurs through the path of MoO3 → MoO2→ Mo2C. The carburized MoO3 was characterized using X-ray diffraction （XRD）, CHNS/O analysis, Brunauer-Emmett-Teller （BET） analysis, and field-emission scanning electron microscopy （FESEM）. At final carburization temperatures of 700 and 800℃ and at methane contents ranging from 5vol% to 20vol%, Mo2C was the only solid product observed in the XRD patterns. The re- suits indicated that the effect of methane content on the formation of the carbide phase is substantial compared with the effect of carburization time. Elemental analysis showed that at a final temperature of 700℃, the carbon content of carburized MoO3 is very close to the theoretical carbon mass percentage in Mo2C. At higher carburization temperatures, excess carbon was deposited onto the surface of Mo2C. High-surface-area Mo2C was obtained at extremely low heating rates; this high-surface-area material is a potential electrocatalyst.

关键词： molybdenum carbide thermodynamic analysis temperature programmed reaction methane

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Synergistic Effect of Nitrogen/Phosphorus Co-Doping and molybdenum carbide Induced Electron Redistribution of Carbon Layer to Boost Hydrogen Evolution Reaction

引用

Chinese Journal of Chemistry 2024年第1期42卷 55-60页

作者： Jiamin Xiao Peng Li Yanyan Sun Heng Liu Javid Khan Handong Zhang Han Zhou Yaqiong Su Shuangyin Wang Lei Han College of Materials Science and Engineering Hunan Joint International Laboratory of Advanced Materials and Technology for Clean EnergyHunan UniversityChangshaHunan 410082China School of Chemistry Engineering Research Center of Energy Storage Materials and Devices Ministry of EducationXi'an Key Laboratory of Sustainable Energy Materials ChemistryState Key Laboratory of Electrical Insulation and Power EquipmentXi'an Jiaotong UniversityXi'anShaanxi 710049China School of Materials Science and Engineering Central South UniversityChangshaHunan 410083China state Key Laboratory of Chem/Bio-Sensingand Chemometrics College of Chemistry and Chemical EngineeringHunan University ChangshaHunan 410082China Laboratory of Inorganic Materials and Catalysis Department of Chemical Engineering and ChemistryEindhoven University of Technology P.O.Box5135600 MB EindhovenThe Netherlands

The development of highly efficient non-precious-metal-based electrocatalysts for the hydrogen evolution reaction is imperative for promoting the large-scale application of electrochemical water ***,nitrogen/phosphorus co-doped carbon nanorods encapsulated Mo_(2)C nanoparticles(Mo_(2)C@PNc)have been prepared by pre-phosphating treatment in combination of the coordination with polydopamine and the subsequent *** phosphating temperature has a significant effect on the content of phosphorus within the resultant Mo_(2)C@PNC,and the optimal catalyst delivers superior HER activity with the low overpotential of 104 mV at a current density of 10 mAcm^(-2) and good stability for 8 h,which has been theoretically demonstrated to originate from the synergistic effect between P doping and Mo_(2)C induced electron redistribution of nitrogen-doped carbon layer.

关键词： molybdenum carbide N/P co-doped carbon Hydrogen evolution Synergistic effect Electron redistribution Comprehensive

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Multiscale confinement nitridation in molybdenum carbide for efficient hydrogen production

引用

Journal of Energy Chemistry 2024年第7期94卷 61-69页

作者： Liming Dai Chenchen Fang Xiaoyuan Zhang Xuefeng Xu Xuanxuan Chen Xinyue Zong Xueming Hu Wenyao Zhang Liang Xue Pan Xiong Yongsheng Fu Jingwen Sun Junwu Zhu Key Laboratory for Soft Chemistry and Functional Materials Ministry of EducationNanjing University of Science and TechnologyNanjing 210094JiangsuChina

The molybdenum carbide(Mo_(2)C)has been regarded as one of the most cost-efficient and stable electrocatalyst for the hydrogen evolution reaction(HER)by the virtue of its Pt-like electronic ***,the inherent limitation of high density of empty valence band significantly reduces its catalytic reactivity by reason of strong hydrogen desorption ***,we propose a multiscale confinement synthesis method to design the nitrogen-rich Mo_(2)C for modulating the band structure via decomposing the pre-coordination bonded polymer in a pressure-tight tube sealing ***-bonded c/N-Mo in the coordination precursor constructs a micro-confinement space,enabling the homogeneous nitrogenization in-situ happened during the formation of Mo_(2)***,the evolved gases from the precursor decomposition in tube sealing system establish a macro-confinement environment,preventing the lattice N escape and further endowing a continuous *** the multiscale confinement effects,the nitrogen-rich Mo2C displays as high as 25%N-Mo concentration in carbide lattice,leading to a satisfactory band ***,the constructed nitrogen-rich Mo_(2)C reveals an adorable catalytic activity for HER in both alkaline and acid *** is anticipated that the multiscale confinement synthesis strategy presents guideline for the rational design of electrocatalysts and beyond.

关键词： molybdenum carbide Hydrogen evolution reaction Multiscale confinement synthesis Valence band modulation Nitrogen doping

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Preparation of ultramicro molybdenum carbide powders and study on wear properties of their coating

引用

Rare Metals 2011年第3期30卷 262-266页

作者： AN Geng LIU Gaojie Technical Center Jinduicheng Molybdenum Co. Ltd Xi＇an 710077 China School of Material Science and Engineering Xi＇an Jiaotong University Xi＇an 710049 China

Using specially designed mechanochemical ball-mill equipment, ultramicro molybdenum carbide （MoC） powders were prepared by high-energy ball milling from pure molybdenum powders in civil coal gas atmosphere at room temperature. The structure and the particle size of the powders were investigated by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and Transmission Electron micros-copy （TEM）. The results showed that after milling for 30 h, the MoC powders of hexagonal structure were obtained, and their average parti-cle size was around 100 nm. It was found that chemisorption of CO in coal gas onto the fresh molybdenum surfaces created by milling was the predominant processes during the solid-gas reaction, and the energy input due to the introduction of highly dense grain boundaries and lattice defects provided the activation energy for the transition from Mo-C chemisorption to MoC. A coating was formed on the 40Cr steel base using plasma spray by mixing Ni60 alloy powders and ultramicro MoC powders of 5 wt.%, 10 wt.%, and 15 wt.%, respectively. Coat-ing abrasion tests under the condition of dry-grinding, 2 h wear time, and 300 N load showed that the wear resistance property of the coating added with ultramicro MoC powders could be improved greatly, and the wear resistance property of the coating increased with the increase of ultramicro MoC content. The wear mechanisms of ultramicro MoC coating is mainly plough wear and flaking wear assisted. In the abra-sion process, the evenly distributed ultramicro MoC particles play a dispersion strengthening and self-lubricating role in the coating.

关键词： powders molybdenum carbide coatings wear resistance ball milling

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Investigation on the Performance of Supported molybdenum carbide for the Partial Oxidation of Methane

引用

Journal of Natural Gas Chemistry 2003年第1期12卷 23-30页

作者： Quanli Zhu, Jian Yang, Jiaxin Wang, Shengfu Ji, Hanqing WangState Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical Physics Chinese Academy of Sciences

The performance of supported and unsupported molybdenum carbide for thepartial oxidation of methane (POM) to syngas was investigated. An evaluation of the catalystsindicates that bulk molybdenum carbide has a higher methane conversion during the initial stage buta lower selectivity to CO and H_2/CO ratio in the products. The rapid deactivation of the catalystis also a significant problem. However, the supported molybdenum carbide catalyst shows a muchhigher methane conversion, increased selectivity and significantly improved catalytic stability. Thecharacterization by XRD and BET specific area measurements depict an improved dispersion ofmolybdenum carbide when using alumina as a carrier. The bulk or the supported molybdenum carbideexists in the β-MO_2C phase, while it is transformed into molybdenum dioxide postcatalysis which isan important cause of molybdenum carbide deactivation.

关键词： molybdenum carbide molybdenum oxide partial oxidation of methane syngas deactivation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Coupled cobalt-doped molybdenum carbide@N-doped carbon nanosheets/nanotubes supported on nickel foam as a binder-free electrode for overall water splitting

引用

Chinese Journal of Catalysis 2019年第9期40卷 1352-1359页

作者： Jiangnan Xing Fei Lin Liutao Huang Yuchang Si Yijing Wang Lifang Jiao Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) Renewable Energy Conversion and Storage CenterCollege of ChemistryNankai UniversityTianjin 300071China Logistics University of People's Armed Police Force Tianjin 300309China

In an attempt to develop low-cost,non-noble-metal bifunctional electrocatalysts for water electrolysis in alkaline media,cobalt-doped molybdenum carbide@N-doped carbon nanosheets/nanotubes were fabricated by using C3N4 as the carbon source on a 3D porous nickel foam *** from the optimized electronic structure and enhanced mass and charge transport,as well as the 3D conducting pathway,MoxCoy@N-CNSs/CNTs shows superior performance towards both the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)in an alkaline *** optimal electrocatalyst is Mo2Co1@N-CNSs/CNTs,which reveals a current density of 10 mA cm^-2 at the low overpotentials of 99 mV and 300 mV for the HER and OER,respectively,and a relatively low cell voltage(1.63 V)for the overall water *** method of optimizing the composition and nanostructure of a material provides a new avenue for the development and utilization of high-performance electrocatalysts.

关键词： molybdenum carbide Cobalt doping Self-supported electrode Overall water splitting

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

XPS study of potassium-promoted molybdenum carbides for mixed alcohols synthesis via CO hydrogenation

引用

Journal of Natural Gas Chemistry 2010年第2期19卷 151-155页

作者： Minglin Xiang Debao Li Juan Zou Wenhuai Li Yuhan Sun Xichun She Hunan Changling Petrochemical S＆T Developing Co. Ltd. Yueyang 414012 Hunan China State Key Laboratory of Coal Conversion Shanxi Institute of Coal Chemistry Chinese Academy of Sciences Taiyuan 030001 Shanxi China

The X-ray photoelectron spectroscopy （XPS） was used to investigate the surface characteristic of potassium-promoted or un-promoted both β-Mo2C and α-MoC1-x pretreated by syngas at different temperatures,and the promotional effect of potassium on the catalytic performance was also *** results revealed that the content of surface Mo and its valence distribution between β-Mo2C and α-MoC1-x were quite *** by potassium,the remarkable changes were observed for surface composition and valence of Mo distribution over β-*** had strong electronic effect on β-Mo2C,which led to a higher Mo4＋ *** the contrary,potassium had little electronic effect on α-MoC1-x,and K-Mo interaction was ***,Mo0 and Mo2＋ became the dominant species on the catalyst surface,and the Mo4＋ content showed almost no increase as the pretreatment temperature *** terms of catalytic performance of molybdenum carbides,the increase in Mo0 most likely explained the increase in hydrocarbon selectivity,yet Mo4＋ might be responsible for the alcohols synthesis.

关键词： molybdenum carbide potassium-promoted CO hydrogenation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effects of carbide Formation in Graphene Growth

引用

Chinese Journal of Chemical Physics 2015年第1期28卷 65-69,I0002页

作者：王准准罗其全张文华李震宇中国科学技术大学合肥微尺度国家实验室合肥230026

Besides carbon solubility, the carbide formation possibility is another important factor to differentiate various substrate materials in graphene growth. A recent experiment indicates that the formation of transition metal carbides （TMCs） can suppress carbon precipitation. In this study, Mo2C, a representative of TMCs, is used to study the effects of carbide formation in graphene growth from first principles. Carbon diffusion in Mo2C bulk turns out to be very difficult and it becomes much easier on the Mo2C（001） surface. Therefore, carbon precipitation suppression and graphene growth can be realized simultaneously. A direction depended diffusion behavior is observed on the Mo2C（101） surface, which makes it less favorable for graphene growth compared to the （001） surface.

关键词： molybdenum carbide Diffusion Density functional theory

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Study on reduction of MoS_2 powders with activated carbon to produce Mo_2C under vacuum conditions

引用

International Journal of Minerals,Metallurgy and Materials 2018年第4期25卷 405-412页

作者： Guo-hua Zhang He-qiang Chang Lu Wang Kuo-chih Chou State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing

A method of preparing Mo2C via vacuum carbothermic reduction of MoS2 in the temperature range of 1350–1550°C was proposed. The effects of MoS2-to-C molar ratio（a, a = 1：1, 1：1.5, and 1：2.5） and reaction temperature（1350 to 1550°C） on the reaction were studied in detail. The phase transition, morphological evolution, and residual sulfur content of the products were analyzed by X-ray diffraction, field-emission scanning electron microscopy, and carbon–sulfur analysis, respectively. The results showed that the complete decomposition of MoS2 under vacuum is difficult, whereas activated carbon can react with MoS2 under vacuum to generate Mo2C. Meanwhile, higher temperatures and the addition of more carbon accelerated the rate of carbothermic reduction reaction and further decreased the residual sulfur content. From the experimental results, the optimum molar ratio α was concluded to be 1：1.5.

关键词： vacuum treatment carbon thermoreduction molybdenum minerals molybdenum carbide microstructure

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：