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Gold/Mg-Al mixed oxides catalysts for oxidative esterification of methacrolein:Effects of support size and composition on gold loading 被引量:1
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作者 Wangtao Li Qiancheng Zheng +2 位作者 Huayu Zhang Yunsheng Dai Zhengbao Wang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第12期128-138,共11页
Gold catalysts supported on Mg-Al mixed oxides for oxidative esterification of methacrolein are prepared by impregnation.Effects of the support particle size,concentration of HAuCl4 solution and Mg/Al ratio on gold lo... Gold catalysts supported on Mg-Al mixed oxides for oxidative esterification of methacrolein are prepared by impregnation.Effects of the support particle size,concentration of HAuCl4 solution and Mg/Al ratio on gold loading and catalytic properties are investigated.The catalysts are characterized by CO_(2)-TPD,EDS,XPS,STEM and XRD techniques.Catalysts with smaller support particle size show more uniform gold distribution and higher gold dispersion,resulting in a higher catalytic performance,and the uniformity of gold and the activity of the catalysts with larger support particle size can be improved by decreasing the concentration of HAuCl4 solution.The Mg/Al molar ratio has significant effect on the uniformity of gold and the activity of the catalyst,and the optimum Mg/Al molar ratio is 0.1–0.2.This study underlines the importance of engineering support particle size,concentration of HAuCl4 solution and density of adsorption sites for efficient gold loading on support by impregnation. 展开更多
关键词 Gold catalysts Oxidative esterification Support particle size effect Mass transfer DISTRIBUTIONS Optimization
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Controlled synthesis of monodispersed spherical ruthenium powders
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作者 Feng-Shuo Xu Hao Cui +7 位作者 Man-Men Liu Jia-Lin Chen Ming Wen Chuan-Jun Wang Wei Wang Song Li Xu-Dong Sun Shao-Hong Liu 《Rare Metals》 SCIE EI CAS CSCD 2023年第12期4246-4254,共9页
Monodispersed spherical Ru powders are essential for fabricating high-performance Ru sputtering targets,which have applications in very-large-scale integration circuits and magnetic recording devices.However,the synth... Monodispersed spherical Ru powders are essential for fabricating high-performance Ru sputtering targets,which have applications in very-large-scale integration circuits and magnetic recording devices.However,the synthesis of such powders remains a major challenge.Here,we reported the synthesis of monodispersed spherical Ru powders through controlling the molar ratio of SO_(4)^(2-)to Ru^(3+)in urea homogeneous precipitation solution and the annealing conditions.Without the addition of(NH4)2SO_(4)into the reaction solution,only gel-like precipitation particles were obtained.Once introducing(NH_(4))_(2)SO_(4) into the reaction solution and controlling the molar ratio of SO_(4)^(2-)to Ru3+between 0.50 and 1.00,monodispersed spherical precursor powders were obtained.The nucleation and growth of monodispersed spherical precursor particles in solution were found to conform to LaMer's model.Through controlled annealing at 450℃in a hydrogen atmosphere,the obtained metallic Ru powder with an average particle size of 135 nm inherited the spherical morphology and excellent dispersity from the monodispersed spherical precursor powders.These results and findings would deepen the understanding of the preparation of monodispersed Ru and Ru-like powders. 展开更多
关键词 RUTHENIUM Sputtering target Spherical powder Integration circuits Magnetic recording
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Elaborating strengthen mechanism of Pt-Ir solid solution superalloy at finite temperature
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作者 Wei Yu Xiao-Yu Chong +9 位作者 Yun-Xuan Zhou Meng-Di Gan Ying-Xue Liang Yan Wei Ai-Min Zhang Chang-Yi Hu Xing-Yu Gao Li Chen Hai-Feng Song Jing Feng 《Rare Metals》 SCIE EI CAS CSCD 2024年第3期1243-1256,共14页
Pt-Ir alloy is potential superalloys used above 1300℃because of their high strength and creep resistance.However,the ductility of Pt-Ir alloy has rapidly deteriorated with the increase of Ir,resulting in poor machina... Pt-Ir alloy is potential superalloys used above 1300℃because of their high strength and creep resistance.However,the ductility of Pt-Ir alloy has rapidly deteriorated with the increase of Ir,resulting in poor machinability.This work quantitatively evaluated the solid solution strengthening(SSS)and grain refinement strengthening(GRS)of Pt-Ir alloy using first-principles calculations combined with experimental characterization.Here,the stretching force constants in the second nearest neighbor region(SFC^(2nd))of pure Ir(193.7 eV·nm^(-2))are 3.40 times that of pure Pt(57.0 eV·nm^(-2)),i.e.,the interatomic interaction is greatly enhanced with the increase of Ir content,which leads to the decrease of ductility,and modulus misfit plays a dominant role in SSS.Then,the physical mechanisms responsible for the hardness(H_(V))of Pt-Ir alloy,using the power-law-scaled function of electron work function coupled SSS and GRS,are attributed to the electron redistribution caused by different Ir content.Furthermore,a thorough assessment of the thermodynamic characteristics of Pt-Ir binary alloy was conducted,culminating in development of a mapping model that effectively relates enmposition,temperature and strength.The results revealed that the compressive strength incrcases with the Ir content,and the highest strength was observed in Pt_(0.25)Ir_(0.75).This study provides valuable insights into the Pt-Ir alloy system. 展开更多
关键词 Elastic properties PHONON Solid solution strengthen Force constants CALPHAD
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Molecular dynamics for electrocatalysis:Mechanism explanation and performance prediction 被引量:3
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作者 Yue Wang Haodong Shao +5 位作者 Chengxu Zhang Feng Liu Jianqiang Zhao Sanyuan Zhu Michael K.H.Leung Jue Hu 《Energy Reviews》 2023年第3期1-22,共22页
Designing low-cost,high-performing electrocatalysts is key to green energy development,yet relying solely on the"synthesis-characterization"catalyst screening model is time-consuming and costly.There are two... Designing low-cost,high-performing electrocatalysts is key to green energy development,yet relying solely on the"synthesis-characterization"catalyst screening model is time-consuming and costly.There are two main applications for Molecular dynamics(MD)simulations in electrochemical reactions:explaining mechanisms and predicting performance,which play important roles in fabricating robust electrocatalysts.MD simulations of electrocatalysis include the adsorption and desorption of reactants,intermediates,and products in this review.The structural changes in active centers under various electric field states,the effects of alkali metal cations,common anions,and pH effects in the electrolyte on the electrocatalytic process are also discussed to reveal the reaction mechanism.Then the prediction of the catalysts performance in specific reaction using MD simulations are introduced.Finally,the optimization and challenges of MD techniques are discussed. 展开更多
关键词 Molecular dynamics simulations ELECTROCATALYSIS Electrolyte solution Explain the mechanism Predictive performance
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