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Carbon dots regulate the interface electron transfer and catalytic kinetics of Pt-based alloys catalyst for highly efficient hydrogen oxidation 被引量:5
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作者 Jie Wu Yunjie Zhou +6 位作者 Haodong Nie Kaiqiang Wei Hui Huang Fan Liao Yang Liu Mingwang Shao Zhenhui Kang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2022年第3期61-67,I0003,共8页
The regulation of interface electron-transfer and catalytic kinetics is very important to design the efficient electrocatalyst for alkaline hydrogen oxidation reaction(HOR).Here,we show the Pt-Ni alloy nanoparticles(P... The regulation of interface electron-transfer and catalytic kinetics is very important to design the efficient electrocatalyst for alkaline hydrogen oxidation reaction(HOR).Here,we show the Pt-Ni alloy nanoparticles(PtNi_(2))have an enhanced HOR activity compared with single component Pt catalyst.While,the interface electron-transfer kinetics of PtNi_(2)catalyst exhibits a very wide electron-transfer speed distribution.When combined with carbon dots(CDs),the interface charge transfer of PtNi_(2)-CDs composite is optimized,and then the PtNi_(2)-5 mg CDs exhibits about 2.67 times and 4.04 times higher mass and specific activity in 0.1 M KOH than that of 20%commercial Pt/C.In this system,CDs also contribute to trapping H^(+)and H_(2)O generated during HOR,tuning hydrogen binding energy(HBE),and regulating interface electron transfer.This work provides a deep understanding of the interface catalytic kinetics of Pt-based alloys towards highly efficient HOR catalysts design. 展开更多
关键词 pt-based alloys Carbon dots Interface electron transfer Interface catalytic kinetics Hydrogen oxidation reaction
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Hydrogenation of 2‐ethylanthraquinone with bimetallic monolithic catalysts: An experimental and DFT study 被引量:7
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作者 Yanyan Guo Chengna Dai Zhigang Lei 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2018年第6期1070-1080,共11页
We studied the hydrogenation of 2‐ethylanthraquinone(eAQ) over Pd/SiO2/COR(COR = cordierite) monometallic and Pd‐M/SiO2/COR(M = Ni, Fe, Mn, and Cu) bimetallic monolithic catalysts, which were prepared by the c... We studied the hydrogenation of 2‐ethylanthraquinone(eAQ) over Pd/SiO2/COR(COR = cordierite) monometallic and Pd‐M/SiO2/COR(M = Ni, Fe, Mn, and Cu) bimetallic monolithic catalysts, which were prepared by the co‐impregnation method. Detailed investigations showed that the particle sizes and structures of the Pd‐M(M = Ni, Fe, Mn, and Cu) bimetallic monolithic catalysts were great‐ly affected by the second metal M and the mass ratio of Pd to the second metal M. By virtue of the small particle size and the strong interaction between Pd and Ni of Pd‐Ni alloy, Pd‐Ni bimetallic monolithic catalysts with the mass ratio of Pd/Ni = 2 achieved the highest H2O2 yield(7.5 g/L) and selectivity(95.3%). Moreover, density functional theory calculations were performed for eAQ ad‐sorption to gain a better mechanistic understanding of the molecule‐surface interactions between eAQ and the Pd(1 1 1) or PdM(1 1 1)(M = Ni, Fe, Mn, and Cu) surfaces. It was found that the high activity of the bimetallic Pd‐Ni catalyst was a result of strong chemisorption between Pd3Ni1(1 1 1) and the carbonyl group of eAQ. 展开更多
关键词 bimetallic MONOLITHIC CATALYST Alloy 2‐Ethylanthraquinone hydrogenationDFT CALCULATION SYNERGISTIC effect
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Efficient electrocatalytic reduction of carbon dioxide to ethylene on copper–antimony bimetallic alloy catalyst 被引量:7
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作者 Shuaiqiang Jia Qinggong Zhu +6 位作者 Haihong Wu Meng’en Chu Shitao Han Ruting Feng Jinghui Tu Jianxin Zhai Buxing Han 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2020年第7期1091-1098,共8页
The exploration of efficient electrocatalysts for the reduction of CO2 to C2H4 is of significant importance but is also a challenging subject.Cu-based bimetallic catalysts are extremely promising for efficient CO2 red... The exploration of efficient electrocatalysts for the reduction of CO2 to C2H4 is of significant importance but is also a challenging subject.Cu-based bimetallic catalysts are extremely promising for efficient CO2 reduction.In this work,we synthesize a series of porous bimetallic Cu–Sb alloys with different compositions for the catalytic reduction of CO2 to C2H4.It is demonstrated that the alloy catalysts are much more efficient than the pure Cu catalyst.The performance of the alloy catalysts depended strongly on the composition.Further,the alloy with a Cu:Sb ratio of 10:1 yielded the best results;it exhibited a high C2H4 Faradaic efficiency of 49.7%and a high current density of 28.5 mA cm?2 at?1.19 V vs.a reversible hydrogen electrode(RHE)in 0.1 M KCl solution.To the best of our knowledge,the electrocatalytic reduction of CO2 to C2H4 using Cu–Sb alloys as catalysts has not been reported.The excellent performance of the porous alloy catalyst is attributed to its favorable electronic configuration,large surface area,high CO2 adsorption rate,and fast charge transfer rate. 展开更多
关键词 Carbon dioxide reduction Ethyene ELECTROCATALYST Copper-antimony bimetallic alloy Synergistic effect
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Predicting and controlling interfacial microstructure of magnesium/aluminum bimetallic structures for improved interfacial bonding 被引量:7
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作者 Ziang Zhu Renhai Shi +2 位作者 Andrew D.Klarner Alan A.Luo Yiqing Chen 《Journal of Magnesium and Alloys》 SCIE EI CAS 2020年第3期578-586,共9页
In this study,an overcasting process followed by a low-temperature(200°C)annealing schedule has been developed to bond magnesium to aluminum alloys.ProCAST software was used to optimize the process parameters dur... In this study,an overcasting process followed by a low-temperature(200°C)annealing schedule has been developed to bond magnesium to aluminum alloys.ProCAST software was used to optimize the process parameters during the overcasting process which lead to Mg/Al bimetallic structures to be successfully produced without formation of Mg-Al intermetallic phases.Detailed microstructure evolution during annealing,including the formation and growth of Al-Mg interdiffusion layer and intermetallic phases(Al12Mg17 and Al3Mg2),was experimentally observed for the first time with direct evidence,and predicted using Calculation of Phase Diagrams(CALPHAD)modeling.Maximum interfacial strength was achieved when the interdiffusion layer formed at the Mg/Al interface reached a maximum thickness the without formation of brittle intermetallic compounds.The precise diffusion modeling of the Mg/Al interface provides an efficient way to optimize and control the interfacial microstructure of Mg/Al bimetallic structures for improved interfacial bonding. 展开更多
关键词 bimetallic structure Interfacial bonding CALPHAD and diffusion modeling Aluminum alloys Magnesium alloys.
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Boosting the water gas shift reaction on Pt/CeO_(2)-based nanocatalysts by compositional modification: Support doping versus bimetallic alloying 被引量:3
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作者 Kun Yuan Xiao-Chen Sun +4 位作者 Hai-Jing Yin Liang Zhou Hai-Chao Liu Chun-Hua Yan Ya-Wen Zhang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2022年第4期241-249,共9页
The water gas shift reaction is of vital significance for the generation and transition of energy due to the application in hydrogen production and industries such as ammonia synthesis and fuel cells.The influence of ... The water gas shift reaction is of vital significance for the generation and transition of energy due to the application in hydrogen production and industries such as ammonia synthesis and fuel cells.The influence of support doping and bimetallic alloying on the catalytic performance of Pt/Ce O_(2)-based nanocatalysts in water gas shift reaction was reported in this work.Various lanthanide ions and 3d transition metals were respectively introduced into the Ce O_(2)support or Pt to form Pt/Ce O_(2):Ln(Ln=La,Nd,Gd,Tb,Yb)and Pt M/Ce O_(2)(M=Fe,Co,Ni)nanocatalysts.The sample of Pt/Ce O_(2):Tb showed the highest activity(TOF at 200℃=0.051 s^(-1))among the Pt/Ce O_(2):Ln and the undoped Pt/Ce O_(2)catalysts.Besides,the sample of Pt Fe/Ce O_(2)exhibited the highest activity(TOF at 200℃=0.12 s^(-1))among Pt M/Ce O_(2)catalysts.The results of the multiple characterizations indicated that the catalytic activity of Pt/Ce O_(2):Ln catalysts was closely correlated with the amount of oxygen vacancies in doped ceria support.However,the different activity of Pt M/Ce O_(2)bimetallic catalysts was owing to the various Pt oxidation states of the bimetals dispersed on ceria.The study of the reaction pathway indicated that both the samples of Pt/Ce O_(2)and Pt/Ce O_(2):Tb catalyzed the reaction through the formate pathway,and the enhanced activity of the latter derived from the increased concentration of oxygen vacancies along with promoted water dissociation.As for the sample of Pt Fe/Ce O_(2),its catalytic mechanism was the carboxyl route with a higher reaction rate due to the moderate valence of Pt along with improved CO activation. 展开更多
关键词 Pt/CeO_(2)catalysts Water–gas shift reaction Support doping bimetallic alloying
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Peculiarities of forming diffusion bimetallic joints of aluminum foam with a monolithic magnesium alloy 被引量:1
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作者 M.Khokhlov D.Ishchenko J.Khokhlova 《Journal of Magnesium and Alloys》 SCIE EI CAS 2016年第4期326-329,共4页
The work is carried out to determine an optimal method to obtain the welded bimetallic joints of monolithic Mg-alloy with porous Al-alloy using gallium as chemical activator and heating up to 300 ℃ by two different m... The work is carried out to determine an optimal method to obtain the welded bimetallic joints of monolithic Mg-alloy with porous Al-alloy using gallium as chemical activator and heating up to 300 ℃ by two different methods:long-term in vacuum oven and short-term without vacuum by passing of low voltage current.There is no microstructure change in Al-foam but indentation test records the negligible reduction of the mechanical properties.SEM showed the crystallization of two types of Mg_(5)Ga_(2) and Mg_(2)Ga inter-metallic phases in the wavy uneven diffusion zone on Mg-alloy side with significant increase of micro-hardness and Young’s modulus.The narrow depth of the diffusion zone takes place in joints by short-term heating,so this method is more applicable for welding of monolithic and porous alloys at chemical activation using gallium. 展开更多
关键词 DIFFUSION Welding bimetallic Aluminum foam Magnesium alloy
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Hydrodeoxygenation of Bio-Oil on Bimetallic Catalysts: From Model Compound to Real Feed 被引量:1
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作者 Thuan Minh Huynh Udo Armbruster +2 位作者 Luong Huu Nguyen Duc Anh Nguyen Andreas Martin 《Journal of Sustainable Bioenergy Systems》 2015年第4期151-160,共10页
Two series of bimetallic Ni-Co catalysts and corresponding monometallic catalysts with ca. 20 wt% metal loading were evaluated in hydrodeoxygenation (HDO) of phenol as a model compound for bio-oil. The bimetallic cata... Two series of bimetallic Ni-Co catalysts and corresponding monometallic catalysts with ca. 20 wt% metal loading were evaluated in hydrodeoxygenation (HDO) of phenol as a model compound for bio-oil. The bimetallic catalysts outperformed the corresponding monometallic catalyst in terms of conversion and cyclohexane selectivity. This could be attributed to the formation of Ni-Co alloy, which caused a decrease in metal particle size and stabilized Ni active sites in the near surface region. The balanced combination of formed Ni-Co alloy with acidity from supports allowed performing all individual steps in the reaction network toward desired products at high rate. Consequently, the two best-performing catalysts were tested in HDO of wood based bio-oil, showing that the bimetallic catalyst 10Ni10Co/HZSM-5 was more effective than 20Ni/HZSM-5 in terms of degree of deoxygenation and upgraded bio-oil yield. These findings might open an opportunity for development of a novel cheap but effective catalyst for a key step in the process chain from biomass to renewable liquid fuels. 展开更多
关键词 bimetallic Catalysts HYDRODEOXYGENATION PHENOL BIO-OIL NI-CO Alloy
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Deformation Characteristics and Mechanical Properties of Ti/Al Bimetallic Composite Materials Fabricated by Wire Plus Arc Additive Manufacturing
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作者 夏玉峰 ZHANG Xue +2 位作者 CHEN Lei JIANG Xianhong LIAO Hailong 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2023年第4期885-892,共8页
We focused on Ti/Al composite materials fabricated by wire and arc addictive manufacturing,and the microstructure and interface characteristics of them before and after hot compression deformation were compared.After ... We focused on Ti/Al composite materials fabricated by wire and arc addictive manufacturing,and the microstructure and interface characteristics of them before and after hot compression deformation were compared.After compression deformation,allαstructures of titanium were compacted with the emergence of Widmanstatten structures.Coarsened coloniesαof titanium were elongated and waved along the original growth direction,resulting in anisotropy of grains.Pores and Ti/Al intermetallic compounds of aluminum are significantly decreased after hot compression.Meanwhile,a good bonding interface between titanium and aluminum is obtained after hot compression,and the element diffusion is more intense.In addition,the mechanical properties and fracture behaviors of Ti/Al composite material with different clad ratio that is defined as the ratio of the thickness of titanium to that of the Ti/Al composite material are investigated by uniaxial tensile test.The experimental results show that the ultimate tensile strength of Ti/Al composite material is between that of single deposited titanium and aluminum,while the elongation of Ti/Al composite material with low clad ratio is lower than that of single aluminum due to the metallurgical reaction.As the clad ratio increases,the two component layers are harder to separate during deformation,which is resulted from the decrease of the inward contraction stress of three-dimensional stress caused by necking of aluminum.This work may promote the engineering application of Ti/Al bimetallic structures. 展开更多
关键词 wire plus arc additive manufacturing aluminium alloy titanium alloy bimetallic composite materials deformation mechanical properties
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An examination of active sites on Au-Ag bimetallic catalysts based on CO oxidation over Au/Ag_2O and a comparison to Ag-contaminated Au powder
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作者 Yasuo Iizuka Yasuhiro Hiragi +1 位作者 Hikaru Yakushiji Takumi Miura 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2016年第10期1712-1720,共9页
There are two theories regarding the origin of the remarkable synergistic effect observed in Au‐Ag bimetallic catalysts when applied to various oxidative reactions. One is based on the importance of the contact inter... There are two theories regarding the origin of the remarkable synergistic effect observed in Au‐Ag bimetallic catalysts when applied to various oxidative reactions. One is based on the importance of the contact interfaces between AgOx regions and the surface of the bulk Au as active working sites, while the other holds that charge transfer from Ag to Au in a surface Au‐Ag alloy causes the catalytic activity. One key point in examining these theories and determining the origin of the synergy in‐volves determining whether or not Ag exists as an oxide or as a metallic alloy on the Au surface. To confirm that enhanced activity results from contact between Ag2O and Au nanoparticles (NPs), a comparative study of catalytic CO oxidation over Au/Ag2O and Ag2O was performed in the present work, using a closed recirculation reaction system. A reaction mixture consisting of a stoichiometric composition of CO and O2 (CO/O2=2/1) was supplied to both catalysts and the resulting pressure decrease rates were tracked, from which the amounts of gas consumed as well as the quantity of CO2 produced were determined. The steady state reactions of both Au/Ag2O and Ag2O did not lead to any meaningful difference in the rate of pressure decrease during the oxidation. The pressure decrease over both catalysts was attributed to the reduction of surface lattice O on Ag2O by CO. The results obtained for Au/Ag2O are in good agreement with previous data resulting from the use of Ag‐contaminated Au powder (Ag/Au‐b) having an oxidized surfaces. This finding suggests that the perimeters between AgOx zones and the bulk Au surface may not function as active sites during CO oxidation. A review of previous results obtained with Ag/Au‐b specimens having so‐called steady state surfaces indicates that AgOx species in such materials are reduced to the 0 state to form a Ag‐Au alloy that provides the active sites. 展开更多
关键词 Gold-silver bimetallic catalyst Synergy effect Carbon monoxide oxidation Active site Gold-silver alloy
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Rational modulation of electronic structure in PtAuCuNi alloys boosts efficient electrocatalytic ethanol oxidation assisted with energy-saving hydrogen evolution
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作者 Hu Yao Yinan Zheng +3 位作者 Xin Yu Songjie Hu Baolian Su Xiaohui Guo 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第6期557-567,I0014,共12页
Compared to conventional electrocatalytic water splitting,electrocatalytic ethanol oxidation reaction(EOR)along with hydrogen production is considered a more energy-efficient strategy.Herein,we prepared a type of nove... Compared to conventional electrocatalytic water splitting,electrocatalytic ethanol oxidation reaction(EOR)along with hydrogen production is considered a more energy-efficient strategy.Herein,we prepared a type of novel quaternary alloy catalyst(PtAuCuNi@NF)that exhibits excellent activity for EOR(0.215 V at 10 mA cm^(-2))and hydrogen evolution reaction(HER)(7 mV at 10 mA cm^(-2)).Experimental results demonstrated that both Cu and Ni modulated the electronic environment around Pt and Au.The electron-rich active center facilitates the rapid adsorption and dissociation of reactants and intermediates for both EOR and HER.Impressively,in the ethanol-assisted overall water splitting(E-OWS),a current density of 10 mA cm^(-2)was achieved at 0.28 V.Moreover,an advanced acid-base self-powered system(A-Bsps)that can achieve a self-powered voltage of 0.59 V was assembled.Accordingly,the self-driven hydrogen production with zero external power supply was realized by integrating A-Bsps with the E-OWS equipment.The interesting results can provide a feasible strategy for designing and developing advanced nanoalloy-based materials for clean energy integration and use in various fields. 展开更多
关键词 pt-based alloy Electronic structure Ethanol oxidation Self-powered system Overall water splitting
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Characteristics evolution of 6009/7050 bimetal slab prepared by direct-chill casting process 被引量:1
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作者 闫光远 毛丰 +4 位作者 陈飞 吴伟 曹志强 王同敏 李廷举 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第4期895-904,共10页
6009/7050 alloy bimetal slab was prepared by a direct-chill (DC) casting process. Homogenizing annealing, hot rolling and T6 treatment were successively performed and their effects on microstructure and properties of ... 6009/7050 alloy bimetal slab was prepared by a direct-chill (DC) casting process. Homogenizing annealing, hot rolling and T6 treatment were successively performed and their effects on microstructure and properties of the slab were studied. The results reveal that the average diffusion layer thickness of as-cast slab, determined by interdiffusion of elements Zn, Cu, Mg and Si, was about 400 μm. Excellent metallurgical bonding was achieved because all tensile samples fractured on the softer 6009 alloy side after homogenizing annealing. After homogenizing annealing plus rolling, the average diffusion layer thickness decreased to 100 μm, while the network structure of 7050 alloy side transformed to dispersive nubby structure. Furthermore, subsequent T6 treatment resulted in diffusion layer thickness up to 200 μm and an obvious increase of the Vickers hardness for both 7050 and 6009 sides. The layered structure of the as-cast 6009/7050 bimetal is retained after hot rolling and T6 treatment. 展开更多
关键词 7050 alloy bimetal slab direct-chill casting heat treatment hot rolling
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A general strategy for bimetallic Pt-based nano-branched structures as highly active and stable oxygen reduction and methanol oxidation bifunctional catalysts 被引量:8
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作者 Wenjuan Lei Menggang Li +5 位作者 Lin He Xun Meng Zijie Mu Yongsheng Yu Frances MRoss Weiwei Yang 《Nano Research》 SCIE EI CAS CSCD 2020年第3期638-645,共8页
The morphology and size of Pt-based bimetallic alloys are known to determine their electrocatalytic performance in reactions relevant to fuel cells.Here,we report a general approach for preparing Pt-M(M=Fe,Co and Ni)b... The morphology and size of Pt-based bimetallic alloys are known to determine their electrocatalytic performance in reactions relevant to fuel cells.Here,we report a general approach for preparing Pt-M(M=Fe,Co and Ni)bimetallic nano-branched structure(NBs)by a simple high temperature solution-phase synthesis.As-prepared Pt-M NBs show a polycrystalline structure and are rich in steps and kinks on the surface,which promote them favorable bifunctional catalytic properties in acidic electrolytes,specifically in terms of the oxygen reduction reaction(ORR)and methanol oxidation reaction(MOR).Specially,Pt-Co NBs/C catalyst shows 6.1 and 5.3 times higher in specific activity(SA)and mass activity(MA)for ORR than state-of-the-art commercial Pt/C catalysts,respectively.Moreover,it exhibits a loss of 4.0%in SA and 14.4%in MA after 10,000 cycles of accelerated durability tests(ADTs)compared with the initial activities.In addition,we also confirmed the superior MOR activity of Pt-Co NBs/C catalyst in acidic electrolytes.For Pt-M NBs with other alloying metals,the ORR and MOR activities are both higher than commercial catalysts and are in the sequence of Pt-Co/C>Pt-Fe/C>Pt-Ni/C>commercial Pt/C(or PtRu/C).The improved activities and durability can benefit from the morphological and compositional effects.This synthesis approach may be applied to develop bifunctional catalysts with enhanced ORR and MOR properties for future fuel cells designs. 展开更多
关键词 pt-based bimetallic alloy nano-branched structure electrocatalysts oxygen reduction reaction methanol oxidation reaction
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合金纳米颗粒原子级分散制备的双位点催化剂中单点Ag1对Pd1在炔烃双烷氧羰基化反应中的促进作用
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作者 李星局 李峥 +8 位作者 冯四全 宋宪根 严丽 母佳利 袁乔 宁丽丽 陈维苗 韩仲康 丁云杰 《Chinese Journal of Catalysis》 SCIE CAS CSCD 2024年第4期282-292,共11页
炔烃烷氧羰基化反应是一种原子经济反应,可以生成α,β-不饱和羧酸、二羧羧酸酯及其衍生物.其中,乙炔的双烷氧羰基化产物(丁烯二酸二酯)可通过两段加氢制备1,4-丁二醇,该反应路径对于生产生物可降解材料聚丁二酸丁二醇酯(PBS)具有重要意... 炔烃烷氧羰基化反应是一种原子经济反应,可以生成α,β-不饱和羧酸、二羧羧酸酯及其衍生物.其中,乙炔的双烷氧羰基化产物(丁烯二酸二酯)可通过两段加氢制备1,4-丁二醇,该反应路径对于生产生物可降解材料聚丁二酸丁二醇酯(PBS)具有重要意义.然而,目前广泛应用的均相Pd基催化体系存在催化剂分离困难、金属流失以及需要添加有机膦配体或各种磺酸助剂等问题,这不仅增加了制备成本,还可能引入不必要的杂质.此外,尽管纳米催化剂在催化领域有着广泛的应用,但大多数纳米催化剂在炔烃双烷氧基羰基化反应中仍表现出反应活性低和稳定性差的问题,这限制了其在工业生产中的应用.相比之下,多相单金属点催化剂因其100%的原子利用率和较好的催化活性而备受关注.然而,由于多相单金属点催化剂具有相对简单的结构和配位环境,其应用仍受到一定的限制.为了克服这一难题,合成具有不同金属的双位点催化剂成为了一个研究热点.双位点催化剂有望进一步释放单金属位点催化剂的潜力,提高反应活性和稳定性.然而,尽管双位点催化剂具有巨大的应用前景,但目前仍面临着制备方法的挑战.如何设计并实用可行地制备出具有高效催化性能的双位点催化剂,是当前科研领域亟待解决的问题.本文提出一种由CO/CH3I混合物诱导分散Pd-Ag合金纳米颗粒的处理方法,用于制备Pd1-Ag1/AC双位点催化剂.利用X射线衍射、X射线光电子能谱和高角环形暗场扫描透射电子显微镜等方法对分散过程进行表征.结果表明,在分散过程中,CO和CH3I与金属发生协同作用,通过配位生成一种独特的双核络合物(PdI2(CO)-I2-AgI)结构.这种络合物结构逐一从合金纳米颗粒上剥落,直至完成原子级的分散.乙炔双烷氧羰基化反应结果表明,与单金属Pd1/AC相比,在相同反应条件下,双位点Pd1-Ag1/AC催化剂上的乙炔转化率提高了2倍.同时,在保持丁烯二酸二酯选择性为98%的情况下,该催化剂循环使用10次后催化剂性能未见明显变化.炔烃底物拓展结果表明,Pd1-Ag1/AC的协同作用不仅可以提高催化活性,而且在高位阻存在的情况下可以提高产物的立体选择性,这表明双位点协同促进作用对炔烃双羰基化反应具有良好的普适性.微分吸附量热表征结果证明了通过碘配体桥连的Pd1和Ag1单金属点之间的协同效应可以增强催化剂对乙炔的吸附能力.此外,结合拓展边X射线精细结构等实验结果,对催化剂的结构变化和反应机理进行了进一步的探究.第一性原理计算得到的反应能垒和过渡态结果表明,乙炔吸附是反应的速率决定步骤.与Pd1/AC相比,Pd1-Ag1/AC催化剂在反应决速步上表现出了更低的活化能,这从热力学和动力学两个层面解释了其具有更好催化性能的原因.Bader电荷分析和投影态密度计算的结果表明,由于Ag1位点的引入,使Pd1-Ag1/AC催化剂的电荷转移能力和吸附能力均得到增强.相较于Pd1/AC,Pd1-Ag1/AC具有更低的形成能,表明Ag1位点不仅可以提升催化活性,也可以增强双位点结构的稳定性.因此,在催化反应中,Ag1位点的存在起到了重要的促进作用,使得Pd1-Ag1/AC催化剂表现出更优异的性能.综上,本文制备的双位点Pd1-Ag1/AC催化剂在乙炔双烷氧羰基化反应中表现出较好的催化活性和稳定性,证明了双位点协同效应的重要性,为高效催化剂的设计和应用提供了新的思路. 展开更多
关键词 协同促进作用 双位点催化剂 原子级分散 合金纳米颗粒 炔烃双烷氧羰基化 稳定性
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TA15/YG8复合管扩散复合工艺设计及其施压阶段的有限元模拟
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作者 胥政 何维均 +3 位作者 田宇禾 李俊杰 袁飞 蒋斌 《精密成形工程》 北大核心 2024年第10期147-155,共9页
目的以制备钛合金/硬质合金叠层复合管为目标,基于钛合金和硬质合金的性能特点,解决使异种管材相互靠近的载荷难以直接施加的问题,设计开发钛合金/硬质合金复合管的扩散复合工艺。方法借鉴颗粒介质成形的基本原理,提出一种钛合金管-硬... 目的以制备钛合金/硬质合金叠层复合管为目标,基于钛合金和硬质合金的性能特点,解决使异种管材相互靠近的载荷难以直接施加的问题,设计开发钛合金/硬质合金复合管的扩散复合工艺。方法借鉴颗粒介质成形的基本原理,提出一种钛合金管-硬质合金管扩散复合方法,并以TA15钛合金和YG8硬质合金为原材料,通过有限元模拟研究了管间间隙、固体颗粒的填充度、固体颗粒的尺寸和管坯长径比等工艺参数对扩散复合施压过程中TA15钛合金管/YG8硬质合金管界面上径向应力分布的影响。结果有限元模拟结果表明,本文设计提出的钛/硬质合金异质管制备工艺确实能将轴向压力转变为径向贴合力,并且可以通过调控下压量满足扩散复合的压力需求(最小径向应力大于10 MPa)。沿轴线方向,钛合金管与硬质合金管之间的径向应力呈不均匀分布,并且受到管间间隙、颗粒填充度、颗粒的尺寸、管坯长径比等参数的影响。管间装配精度越高、固体颗粒尺寸越小、固体颗粒的填充度越多,越有益于管坯之间的扩散复合。试验结果表明,TA15钛合金/YG8硬质合金复合管在不同部位皆实现了良好的冶金结合。结论设计开发了一种钛合金/硬质合金复合管扩散复合方法,制备出具有良好冶金结合界面的TA15钛合金/YG8硬质合金复合管。 展开更多
关键词 双金属复合管 钛合金 扩散复合 有限元模拟 复合界面
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Porous carbon polyhedrons coupled with bimetallic CoNi alloys for frequency selective wave absorption at ultralow filler loading 被引量:7
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作者 Yan-Li Wang Guang-Sheng Wang +1 位作者 Xiao-Juan Zhang Chen Gao 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2022年第8期34-41,共8页
Combining suitable microstructure and dielectric-magnetic synergy effect is conducive to achieve lightweight,broadband,and high-efficiency microwave absorbing materials within low filler loading.Herein,porous carbon p... Combining suitable microstructure and dielectric-magnetic synergy effect is conducive to achieve lightweight,broadband,and high-efficiency microwave absorbing materials within low filler loading.Herein,porous carbon polyhedrons coupled with bimetallic CoNi alloys were synthesized by using metalorganic frameworks(MOFs)as a template and subsequent pyrolysis treatment.Electromagnetic analysis indicated that the existence of metal Ni element could influence the wave attenuation capacity effectively,resulting in frequency selective wave absorption performance.Additionally,the pyrolysis temperature was also closely related to wave absorption intensity.The Co_(2)Ni_(1)/C/PVDF composites calcined at 800℃ possessed outstanding wave absorption performance at an ultra-low filler loading of 5 wt%.The minimum reflection loss value achieved-52 dB(10.8 GHz)under the matched thickness of 3 mm.Moreover,the broadest effective absorption bandwidth(RL<-10 dB)reached 6.2 dB(11.8-18 GHz)for Co/C-800/PVDF composites when the thickness turned into 2 mm.The remarkable wave attenuation ability was mainly ascribed to magnetic and dielectric loss,impedance matching as well as porous structure effect. 展开更多
关键词 Porous carbon polyhedrons bimetallic CoNi alloys Frequency selective wave
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Facile synthesis of W-Mo bimetallic oxides with high adsorption properties from secondary resources
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作者 Jia-Li Cheng Yang-Si Liu +1 位作者 Xiao-Li Xi Zuo-Ren Nie 《Tungsten》 EI CSCD 2024年第4期806-820,共15页
A simple solvothermal method was used to obtain W-Mo bimetallic oxides from W-Mo alloy scrap,and pure metal powders were also used as the raw materials to simulate scrap.The products had a sea urchin-like structure wi... A simple solvothermal method was used to obtain W-Mo bimetallic oxides from W-Mo alloy scrap,and pure metal powders were also used as the raw materials to simulate scrap.The products had a sea urchin-like structure with abundant oxygen vacancies and the products prepared at low temperatures forms a sosoloid resembling orthorhombic W_(0.4)Mo_(0.6)O_(3).The WMo bimetallic oxide prepared at the reaction temperature of 120℃exhibited excellent selective adsorption performance for methylene blue(MB),which the adsorption rate of MB reached 99%in 12 min and the adsorption rate reached 90%after6 adsorption cycles.When the W-Mo molar ratio is 1:3,the maximum adsorption capacity of sample for MB can reach1148 mg·g^(-1).The adsorption process followed the Langmuir and pseudo-second-order models,which is surface-controlled monolayer adsorption.The experimental results show the feasibility of preparing W-Mo bimetal oxide products from pure materials and scrap.The process is simple and effective,which offered a potential approach for secondary resource recycling and reusing. 展开更多
关键词 W-Mo bimetallic oxide Oxygen vacancy Selective adsorption W-Mo alloy scrap SOLVOTHERMAL
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Pt基双金属催化对硝基苯酚还原反应
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作者 夏新萍 吴飞雄 +3 位作者 朱筱庭 林乐 许嘉伟 许昊翔 《化学反应工程与工艺》 CAS 2024年第5期394-402,共9页
对硝基苯酚(4-NP)是具有一定代表性的水体污染物,使用硼氢化钠将其还原转化为对氨基苯酚,是可行的4-NP污染水体处理手段。本工作通过优化Pt基合金组分与比例,筛选出催化硼氢化钠催化还原4-NP活性高的TiO_(2)负载铂铜纳米合金(Pt_(2)Cu_(... 对硝基苯酚(4-NP)是具有一定代表性的水体污染物,使用硼氢化钠将其还原转化为对氨基苯酚,是可行的4-NP污染水体处理手段。本工作通过优化Pt基合金组分与比例,筛选出催化硼氢化钠催化还原4-NP活性高的TiO_(2)负载铂铜纳米合金(Pt_(2)Cu_(3)/TiO_(2))。通过动力学实验,把Pt_(2)Cu_(3)/TiO_(2)催化4-NP还原反应的“时间-浓度”数据转化为“反应速率-浓度”数据,证实该反应为一级反应并建立幂指数型动力学方程。依据Langmuir-Hinshelwood(L-H)吸附反应机理,回归拟合本征动力学方程式的未知参数,包括反应速率常数、反应底物吸附常数、表观活化能等热力学参数。 展开更多
关键词 对硝基苯酚还原 双金属纳米合金催化剂 催化反应动力学方程 反应器模拟与设计
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铝/铝双金属复合材料制备技术研究进展
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作者 王旭忠 李晓飞 王高松 《有色金属加工》 CAS 2024年第2期4-9,共6页
文章概述了当前铝/铝双金属复合材料制备的几种不同工艺,简述了其优缺点,并分析和展望了铝/铝双金属复合材料在未来的发展趋势。
关键词 双金属复合材料 铝合金 制备工艺
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双金属液液复合界面净化剂的研究及应用
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作者 邢万里 武洁花 +3 位作者 常连波 邢振国 白华彬 魏儒赞 《当代化工研究》 CAS 2024年第15期81-83,共3页
本文通过SEM元素分析、ICP等表征手段,揭示了净化剂的形貌和结构特征,发现硼酸和硅酸盐的含量以及配制方法对净化剂的性能影响较大。优化了净化剂产品配方,开发了双金属液液复合界面净化剂,将双液第一层金属液界面凝固时间缩短6~10 s,... 本文通过SEM元素分析、ICP等表征手段,揭示了净化剂的形貌和结构特征,发现硼酸和硅酸盐的含量以及配制方法对净化剂的性能影响较大。优化了净化剂产品配方,开发了双金属液液复合界面净化剂,将双液第一层金属液界面凝固时间缩短6~10 s,实现了快冷、防氧化和净化作用。不仅便于连续生产,同时界面扩散宽度增加49%,界面结合强度提高了41.5%,冲击韧性提高了15.6%。 展开更多
关键词 双金属 液液复合 界面 净化剂 高铬铸铁 合金钢
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ZChSnSb11-6/20号钢双金属复合材料的扩散连接 被引量:6
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作者 邹军涛 赵艳 +2 位作者 王婵 杨晓红 梁淑华 《中国有色金属学报》 EI CAS CSCD 北大核心 2016年第7期1451-1458,共8页
为了获得较高的界面结合强度,对20号钢表面采用热浸镀锡处理后,进行液固扩散连接,制备ZChSnSb11-6/20号钢双金属复合材料。采用扫描电子显微镜(SEM),X射线衍射仪(XRD)表征了ZChSnSb11-6/20号钢结合过渡区的形貌及其元素分布,并对其硬度... 为了获得较高的界面结合强度,对20号钢表面采用热浸镀锡处理后,进行液固扩散连接,制备ZChSnSb11-6/20号钢双金属复合材料。采用扫描电子显微镜(SEM),X射线衍射仪(XRD)表征了ZChSnSb11-6/20号钢结合过渡区的形貌及其元素分布,并对其硬度和界面结合强度进行检测。结果表明:通过20号钢热浸镀锡后,再进一步进行液固扩散可以制备结合面均匀稳定的ZChSnSb11-6/20号钢双金属复合材料,20号钢中Fe与Sn形成一层互扩散组织的结合过渡层,实现了20号钢与巴氏合金ZChSnSb11-6的冶金结合;结合过渡区的硬度明显高于两侧基体的,界面结合强度可达60.15MPa。 展开更多
关键词 ZChSnSb11-6合金 双金属复合材料 过渡区 热浸镀 扩散连接
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