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Adsorption of HCN on Ni/Pt(111)Bimetallic Surfaces Investigated with Density Functional Theory Method
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作者 黄攀 史晓琪 +3 位作者 冯晓宁 刘建治 李奕 章永凡 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2016年第10期1491-1500,共10页
We applied periodic density-functional theory to investigate the adsorption of HCN on x Ni@Pt(111) bimetallic surfaces(x = 1~4). The results have been compared with those obtained on pure Ni(111) and Pt(111) s... We applied periodic density-functional theory to investigate the adsorption of HCN on x Ni@Pt(111) bimetallic surfaces(x = 1~4). The results have been compared with those obtained on pure Ni(111) and Pt(111) surfaces. For all bimetallic surfaces,HCN is preferentially tilted with the CN bond parallel to the surface,and adsorption energies increase with an increasing number of layer Ni atoms on the surface. The adsorption energies of HCN on all bimetallic surfaces are larger than that on the Pt(111) surface,whereas the adsorption energies of HCN on 3Ni@Pt(111) and 4Ni@Pt(111) are larger than that on the Ni(111) surface,indicating that the introduction of Ni to the Pt catalyst could increase the activity of bimetallic catalyst in the hydrogenation reaction for nitriles. Larger adsorption energy of HCN leads to a longer C–N bond length and a smaller CN vibrational frequency. The analysis of Bader charge and vibrational frequencies showed obvious weakening of the adsorbed C–N bond and an indication of sp2 hybridization of both carbon and nitrogen atoms. 展开更多
关键词 hydrogen cyanide ni/Pt(111) bimetallic surfaces density functional theory
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Characteristics of La-modified Ni-Al_2O_3 and Ni-SiO_2 catalysts for CO_x-free hydrogen production by catalytic decomposition of methane 被引量:3
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作者 Chatla Anjaneyulu Velisoju Vijay Kumar +1 位作者 Suresh K.Bhargava Akula Venugopal 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2013年第6期853-860,共8页
Hydrotalcite precursors of La modified Ni-Al2O3 and Ni-SiO2 catalysts prepared by co-precipitation method and the catalytic activities were examined for the production of COx-free H2 by CH4 decomposition. Physico-chem... Hydrotalcite precursors of La modified Ni-Al2O3 and Ni-SiO2 catalysts prepared by co-precipitation method and the catalytic activities were examined for the production of COx-free H2 by CH4 decomposition. Physico-chemical characteristics of fresh, reduced and used catalysts were evaluated by XRD, TPR and O2 pulse chemisorptions, TEM and BET-SA techniques. XRD studies showed phases due to hydrotalcite-like precursors in oven dried form produced dispersed NiO species upon calcination in static air above 450 C. Raman spectra of deactivated samples revealed the presence of both ordered and disordered forms of carbon. Ni-La-Al2O3catalyst with a mole ratio of Ni : La : Al = 2 : 0.1 : 0.9 exhibited tremendously high longevity with a hydrogen production rate of 1300 molH2 mol 1 Ni. A direct relationship between Ni metal surface area and hydrogen yields was established. 展开更多
关键词 CH4 decomposition ni-La-Al hydrotalcite ni metal surface area COx-free H2
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Microstructure of Ni /WC Surface Composite Layer on Gray Iron Substrate 被引量:2
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作者 杨贵荣 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2011年第5期861-866,共6页
The surface infiltrated composite (Ni/WC) layers on gray iron substrate were fabricated through a vacuum infiltration casting technique (VICT) using Ni-based composite powder with different WC particles content as... The surface infiltrated composite (Ni/WC) layers on gray iron substrate were fabricated through a vacuum infiltration casting technique (VICT) using Ni-based composite powder with different WC particles content as raw materials.The microstructures of surface infiltrated composite layer,the interface structures between surface composite layer and the substrate,the changes of macro-hardness with the increasing of WC content and the micro-hardness distribution are investigated.The infiltrated composite layer includes a surface composite layer and a transition layer,and the thickness of the transition layer decreases with the increasing content of WC.The thickness of transition layer with 20%WC content in the surface infiltrated composite layer was 170 μm which was the thickest for all transition layers with different WC content.The surface composite layer was mainly composed of WC,W2C,FeB and NiB,along with Ni-Cr-Fe,Ni (Cr) solid solution,Ni (Si) solid solution and Ni (Fe) solid solution.The transition layer was composed of Ni (Cr) solid solution,Ni (Fe) solid solution,Ni (Si) solid solution,Fe (Ni) solid solution and eutectic.The surface macro-hardness and micro-hardness of the infiltrated layer had been evaluated.The macro-hardness of the surface composite layer decreases with the WC content increasing,and the average macro-hardness is HRC60.The distribution of micro-hardness presents gradient change.The average micro-hardness of the infiltrated layer is about HV1000. 展开更多
关键词 ni/WC surface composite layer vacuum infiltration casting technique gray iron substrate MICROSTRUCTURE hardness of the infiltrated composite layer
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Preparation of highly active MCM-41 supported Ni_2P catalysts and its dibenzothiophene HDS performance 被引量:1
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作者 Hua Song Qi Yu +2 位作者 Yanguang Chen Yuanyuan Wang Ruixia Niu 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第3期540-544,共5页
Highly active MCM-41 supported nickel phosphide catalysts for hydrodesulfurization (HDS) were synthesized by two different phosphorus sources, in which the surface of Ni2P catalysts were modified by air instead of b... Highly active MCM-41 supported nickel phosphide catalysts for hydrodesulfurization (HDS) were synthesized by two different phosphorus sources, in which the surface of Ni2P catalysts were modified by air instead of being passivated by O2/N2 mixture. In addition, the catalysts need not be activated with flowing H2 (30 ml·min^-1) at 500℃ for 2 h prior to reaction as traditional method. X-ray diffraction (XRD), X-ray photoelectro spectroscopy (XPS), N2-adsorption specific surface area measurements and CO chemisorption were used to characterize the resulting catalysts. The effect of modification with air on the surface of the catalysts for HDS performance was investigated. Results showed that the surface modification with air can promote the formation of smaller Ni2P particles and more active Ni sites on surface of catalysts. At 3.0 MPa and 613 K, the dibenzothiophene (DBT) conversion of the catalysts modified with air was 98.7%, which was 7.1% higher than that of catalyst passivated by O2/N2 mixture. The higher activities of Ni2P(x)/M41-O catalysts can be attributed to the smaller Ni2P particles sizes and the increased hydrogen dissociation activity due to the surface modification. 展开更多
关键词 ni2P Hydrodesulfurization Passivation Surface modification Dibenzothiophene
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MOLECULAR BEAM STUDIES ON ADSORPTION-DESORPTION KINETICS OF CO AND H_2 ON Ni SURFACE
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作者 Guang Kang XI Jian LIU Sheng Lin LI Tian Xi HE Department of Electron Science, Nankai University, Tianjin 300071 《Chinese Chemical Letters》 SCIE CAS CSCD 1993年第11期965-968,共4页
Adsorption-desorption kinetics of CO and H_2 on Ni surface were studied with molecular beam relaxation spectrometry. It is found that there are two adsorbed states in the substrate temperature range 330K<T<480K ... Adsorption-desorption kinetics of CO and H_2 on Ni surface were studied with molecular beam relaxation spectrometry. It is found that there are two adsorbed states in the substrate temperature range 330K<T<480K and 720K<T<900K respectively for CO/Ni system. These results can be explained by a precursor state model. Their kinetic parameters: E_(aα)=14.6kJ/mol, E_(dx)=49.3kJ/mol; E_(aβ)= 68.6kJ/mol, E_(dβ)=200.6kJ/mol. It is shown that there are two adsorbed states in the low (350K<T<430K) and high (550K<T<625K) temperature range respectively for H_2/Ni system. These results can be explained by a direct dissociative model. Their kinetic parameters:E_(dl)=26.3kJ/mol, E_(dh)=103.7kJ/mol. 展开更多
关键词 MOLECULAR BEAM STUDIES ON ADSORPTION-DESORPTION KINETICS OF CO AND H2 ON ni SURFACE HIGH CO ni
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A MOLECULAR BEAM INVESTIGATION ON ACTIVATED CHEMISORPTION OF N_2 ON Ni SURFACE AND La FILM
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作者 Shumin Shao, Guangkang Xi, Junrong Wang, Shenglin Li Xuezhu Yang, Jinhe Wang, Tianxi He, Baoxia Yu Department of Electron Science, Nankai University, 300071 Tianjin, China 《真空科学与技术学报》 EI CAS CSCD 1992年第Z1期263-266,共4页
The activated chemisorption of N<sub>2</sub> on Ni (poly) and La film was performed on a molecular beam—surface scattering apparatus. Experimental results indicate that the initial sticking probability ... The activated chemisorption of N<sub>2</sub> on Ni (poly) and La film was performed on a molecular beam—surface scattering apparatus. Experimental results indicate that the initial sticking probability s<sub>o</sub> increases linearly from 0 to 0.03 as normal component of translational energy of the molecuar beam E<sub>n</sub> increases from 11.00 to 19.91 kcal/mol for N<sub>2</sub>/Ni system and S<sub>0</sub> from 0 to 0. 10 as E<sub>n</sub> from 10. 40 to 19.91 kcal/mol for N<sub>2</sub>/La system. The apparent activation energy △E are 6.16 kcal/mol and 5.30 kcal/mol for N<sub>2</sub>/Ni and N<sub>2</sub>/La systems respectively. 展开更多
关键词 PRO A MOLECULAR BEAM INVESTIGATION ON ACTIVATED CHEMISORPTION OF N2 ON ni SURFACE AND La FILM LA ni
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A Density Functional Theory Study on the Adsorption of CN on Ni(111) Surface
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作者 LIYi HUJian-Ming LIJun-Qian 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2005年第4期387-394,共8页
The interaction of cyanide (CN) with different sites on Ni(111) surface is studied by using density functional theory (DFT). Ni19 cluster is used to simulate the surface. The present calculations show that the end-o... The interaction of cyanide (CN) with different sites on Ni(111) surface is studied by using density functional theory (DFT). Ni19 cluster is used to simulate the surface. The present calculations show that the end-on bonded (through C atom) configuration is much more preferable than the side-on bonded CN or other configurations on the same adsorption site. For all adsorption modes, adsorption energies at the top, bridge, and three-fold sites on Ni(111) are comparable, with the bridge site of the end-on bonded CN (through C atom) more favorable than other adsorption sites. CN vibrational frequencies are red-shifted at all cases, except that the end-on CN bonded (through C atom) on the top site is blue-shifted. The bonding of CN on the Ni(111) surface is large- ly ionic. 展开更多
关键词 density functional theory ADSORPTION CYAniDE ni(111) surface
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Investigation on Cracking in the Surfacing Welding Layer of Ni_3Al Based Alloy
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作者 Guangwei HAN Di FENG and Wujun YE (Dept.5, Central Iron and Steel Research Institute, Beijing, 100081, China)(To whom correspondence should be addressed) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1994年第5期347-350,共4页
Investigation has been made into the causes of cracking in the Surfacing welding layer of Ni3Al based alloy by analysing both the liqu id-to-solid transformation in the molten pool and the distribution of thermal stre... Investigation has been made into the causes of cracking in the Surfacing welding layer of Ni3Al based alloy by analysing both the liqu id-to-solid transformation in the molten pool and the distribution of thermal stress within the surfacing welding layer. The results show that cracking in the surfacing welding layer is directly related to the producing of eutectic phase β' (NiAl) in the interdendritic region and high thermal stress within the surfacing welding layer. When the process of electric arc surfacing welding is changed from along straight line to along' Z' pattern, cracking in the surfacing welding layer of Ni3Al based alloy is prevented due to being reduced of both the cooling rate of liquid in the molten pool and the moving speed of the heat source. Reducing the melting volume of the substrate material by lowering the output power of electric arc welding would make the content of iron atoms in the molten pool decrease. and this also can reduce the trend of the eutectic reaction in the interdendfitic region and is helpful to Suppress cracking in the surfacing welding layer. 展开更多
关键词 Al Investigation on Cracking in the Surfacing Welding Layer of ni3Al Based Alloy ni
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Co and Ni single sites on the(111)n surface ofγ-Al2O3–a periodic boundary DFT study
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作者 Jiande Gu Jing Wang Jerzy Leszczynski 《Industrial Chemistry & Materials》 2023年第1期117-128,共12页
The influences of increasing the number of d-electrons in the single metal(Fe-like)substituted(111)n surface ofγ-Al2O3 on its possible catalytic effects were explored.The energetic properties,local structures,and in-... The influences of increasing the number of d-electrons in the single metal(Fe-like)substituted(111)n surface ofγ-Al2O3 on its possible catalytic effects were explored.The energetic properties,local structures,and in-site electron configurations of the most active tri-coordinated Co and Ni single-site(111)n surface ofγ-Al2O3 have been studied using the density functional theory(DFT)approach under periodic boundary conditions.The replacement of Al by a Co or Ni atom on the I position of the(111)n surface leads to significant elongations of metal–O distances.The energy released from the substitution process on the AlI site of the(111)n surface follows the sequence NiI(164.85 kcal mol−1)>CoI(113.17 kcal mol−1)>FeI(44.30 kcal mol−1).The triplet and quintet(ground state)of the CoI substituted complex are energy degenerate.Also,the doublet and quartet(ground state)of the NiI substituted complex have the same stable energy.This energy degeneracy comes from theα–βelectron flipping on the p-orbital of the neighboring O that is next to the substituted CoI or NiI site on the(111)n surface ofγ-Al2O3.Different from the FeI substituted single-site(111)n surface,in which the electron configuration of FeI varies according to its spin-multiplicity state,substituted NiI has a unique d8 electron configuration in all three spin states,and similarly,CoI has a unique d7 electron configuration in all three open shell spin states.An increase of the population of d-electrons in the single metal substituted(111)n surface ofγ-Al2O3 is likely to provide a more stable electron configuration in the metal catalytic center. 展开更多
关键词 Co substituted surface ofγ-Al2O3 ni substituted surface ofγ-Al2O3 (111)n surface Periodic boundary DFT approach Metal catalytic center
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