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Towards the insights into the deactivation behavior of acetylene hydrogenation catalyst
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作者 Hai-Xia Su Yang Jiao +8 位作者 Jian-Gong Shi Zhi-Wei Yuan Di Zhang Xu-Peng Wang Jing Ren Dan Liu Jian-Zhou Gui Hai-Yang Gao Xiao-Li Xu 《Petroleum Science》 SCIE EI CAS CSCD 2024年第2期1405-1414,共10页
A series of model catalysts were obtained by treating commercial fresh and spent catalysts unloaded from the factory with different methods, including green oil dipping, extraction and high-temperature regeneration;fi... A series of model catalysts were obtained by treating commercial fresh and spent catalysts unloaded from the factory with different methods, including green oil dipping, extraction and high-temperature regeneration;finally, the deactivation behavior of the commercial catalyst for acetylene hydrogenation were studied. The influence of various possible deactivation factors on the catalytic performance was elucidated via detailed structural characterization, surface composition analysis, and activity evaluation.The results showed that green oil, carbon deposit and sintering of active metal were the main reasons for deactivation, among which green oil and carbon deposit led to rapid deactivation, while the activity could be recovered after regeneration by high-temperature calcination. The sintering of active metal components was attributed to the high-temperature regeneration in hydrothermal conditions, which was slow but irreversible and accounted for permanent deactivation. Thus, optimizing the regeneration is expected to extend the service life of the commercial catalyst. 展开更多
关键词 ACETYLENE HYDROGENATION Green oil carbon deposit SINTERING catalyst deactivation
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Insight into MgO promoter with low concentration for the carbon-deposition resistance of Ni-based catalysts in the CO_2 reforming of CH_4 被引量:3
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作者 Xiangdong Feng Jie Feng Wenying Li 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2018年第1期88-98,共11页
The CO2reforming of CH4is studied over MgO‐promoted Ni catalysts,which were supported on alumina prepared from hydrotalcite.This presents an improved stability compared with non‐promoted catalysts.The introduction o... The CO2reforming of CH4is studied over MgO‐promoted Ni catalysts,which were supported on alumina prepared from hydrotalcite.This presents an improved stability compared with non‐promoted catalysts.The introduction of the MgO promoter was achieved through the‘‘memory effect’’of the Ni‐Al hydrotalcite structure,and ICP‐MS confirmed that only0.42wt.%of Mg2+ions were added into the Ni‐Mg/Al catalyst.Although no differences in the Ni particle size and basicity strength were observed,the Ni‐Mg/Al catalyst showed a higher catalytic stability than the Ni/Al catalyst.A series of surface reaction experiments were used and showed that the addition of a MgO promoter with low concentration can promote CO2dissociation to form active surface oxygen arising from the formation of the Ni‐MgO interface sites.Therefore,the carbon‐resistance promotion by nature was suggested to contribute to an oxidative environment around Ni particles,which would increase the conversion of carbon residues from CH4cracking to yield CO on the Ni metal surface.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved. 展开更多
关键词 CO2 reforming of CH4 carbondeposition resistant Activation of CO2 Ni‐based catalyst Low concentration MgO promoter
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One-step floating conversion of biomass into highly graphitized and continuous carbon nanotube yarns 被引量:1
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作者 Gongxun Zhai Qianqian Wang +5 位作者 Fuyao Liu Zexu Hu Chao Jia Dengxin Li Hengxue Xiang Meifang Zhu 《Green Energy & Environment》 SCIE EI CAS CSCD 2023年第6期1711-1718,共8页
The rapid growth of the demand for carbon nanotubes(CNTs) has greatly promoted their large-scale synthesis and development. However,the continuous production of CNT fibers by floating catalyst chemical vapor depositio... The rapid growth of the demand for carbon nanotubes(CNTs) has greatly promoted their large-scale synthesis and development. However,the continuous production of CNT fibers by floating catalyst chemical vapor deposition(FCCVD) requires a large amount of non-renewable carbon sources. Here, the continuous production of highly graphitized CNT yarns from biomass tannic acid(TA) is reported. The chelation of TA and catalyst promotes the rapid cracking of biomass into carbon source gas, and the pyrolysis cracking produces the reducing gas, which solves the problems of the continuous production of CNT yarns using biomass. Through simple twisting, the mechanical strength of CNT yarn can reach 886 ± 46 MPa, and the electrical conductivity and graphitization(IG/ID) can reach 2 × 10^(5)S m^(-1)and 6.3, respectively. This work presents a promising solution for the continuous preparation of CNT yarns based on green raw material. 展开更多
关键词 carbon nanotube Tannic acid BIOMASS Pyrolysis Floating catalyst chemical vapor deposition
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Synthesis of Carbon Nanotubes using Cu-Cr-O as Catalyst by Chemical Vapor Deposition
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作者 赵腾腾 刘萍 +3 位作者 CHEN Xiaohong ZHAO Chunjing LIU Xinkuan LI Wei 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2014年第5期928-932,共5页
A novel powder catalyst Cu-Cr-O applied to the synthesis of carbon nanotubes (CNTs) was developed, which was prepared via ammonia precipitation method. Techniques of thermo-gravimetric/ differential scanning calorim... A novel powder catalyst Cu-Cr-O applied to the synthesis of carbon nanotubes (CNTs) was developed, which was prepared via ammonia precipitation method. Techniques of thermo-gravimetric/ differential scanning calorimeter (TG-DSC), X-ray diffraction (XRD) as well as scanning electron microscopy (SEM) and transmission electron microscopy (TEM) have been employed to characterize the thermal decomposition procedure, crystal phase and micro structural morphologies of the as-synthesized materials, respectively. The results show that carbon nanotubes are successfully synthesized using Cu-Cr-O as catalyst when the precursors are calcined at 400, 500, 600, and 700 ℃. The results indicate that the calcination of the Cu-Cr-O catalyst at 600 ℃ is an effective method to get MWCNT with few nano-tube defects or amorphous carbons. 展开更多
关键词 carbon nanotubes Cu-Cr-O catalyst chemical vapor deposition calcined temperature
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Synthesis of multi-walled carbon nanotubes using CoMnMgO catalysts through catalytic chemical vapor deposition
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作者 杨文 冯艳艳 +1 位作者 江成发 储伟 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第12期528-532,共5页
The Co Mg O and Co Mn Mg O catalysts are prepared by a co-precipitation method and used as the catalysts for the synthesis of carbon nanotubes(CNTs) through the catalytic chemical vapor deposition(CCVD). The effec... The Co Mg O and Co Mn Mg O catalysts are prepared by a co-precipitation method and used as the catalysts for the synthesis of carbon nanotubes(CNTs) through the catalytic chemical vapor deposition(CCVD). The effects of Mn addition on the carbon yield and structure are investigated. The catalysts are characterized by temperature programmed reduction(TPR) and X-ray diffraction(XRD) techniques, and the synthesized carbon materials are characterized by transmission electron microscopy(TEM) and thermo gravimetric analysis(TG). TEM measurement indicates that the catalyst Co Mg O enclosed completely in the produced graphite layer results in the deactivation of the catalyst. TG results suggest that the Co Mn Mg O catalyst has a higher selectivity for CNTs than Co Mg O. Meanwhile, different diameters of CNTs are synthesized by Co Mn Mg O catalysts with various amounts of Co content, and the results show that the addition of Mn avoids forming the enclosed catalyst, prevents the formation of amorphous carbon, subsequently promotes the growth of CNTs, and the catalyst with decreased Co content is favorable for the synthesis of CNTs with a narrow diameter distribution.The Co Mn Mg O catalyst with 40% Co content has superior catalytic activity for the growth of carbon nanotubes. 展开更多
关键词 Co Mn Mg O catalyst carbon nanotubes chemical vapor deposition methane decomposition
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Investigation and Mitigation of Carbon Deposition over Copper Catalyst during Electrochemical CO_(2)Reduction 被引量:2
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作者 Jing-Wen DuanMu Zhi-Zheng Wu +5 位作者 Fei-Yue Gao Peng-Peng Yang Zhuang-Zhuang Niu Yu-Cai Zhang Li-Ping Chi Min-Rui Gao 《Precision Chemistry》 2024年第4期151-160,共10页
Copper(Cu)is considered to be the most effective catalyst for electrochemical conversion of carbon dioxide(CO_(2))into value-added hydrocarbons,but its stability still faces considerable challenge.Here,we report the p... Copper(Cu)is considered to be the most effective catalyst for electrochemical conversion of carbon dioxide(CO_(2))into value-added hydrocarbons,but its stability still faces considerable challenge.Here,we report the poisoning effect of carbon deposition during CO_(2)reduction on the active sites of Cu electrodea critical deactivation factor that is often overlooked.We find that,*C,an intermediate toward methane formation,could desorb on the electrode surface to form carbon species.We reveal a strong correlation between the formation of methane and the carbon deposition,and the reaction conditions favoring methane production result in more carbon deposition.The deposited carbon blocks the active sites and consequently causes rapid deterioration of the catalytic performance.We further demonstrate that the carbon deposition can be mitigated by increasing the roughness of the electrode and increasing the pH of the electrolyte.This work offers a new guidance for designing more stable catalysts for CO_(2)reduction. 展开更多
关键词 carbon deposition ROUGHNESS in situ spectrum CO_(2)electroreduction copper catalyst
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Study on Diameter Controlled Growth of Carbon Nanotubes by LaAl_(1-x)Fe_xO_3 Catalysts 被引量:2
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作者 PENGFeng WANGHong-juan 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2005年第1期4-7,共4页
A series of LaAl 1-xFe xO 3 catalysts prepared with lanthanum nitrate, aluminium nitrate and iron nitrate was investigated in catalytical syntheses of carbon nanotubes with high yields and purity. The properties ... A series of LaAl 1-xFe xO 3 catalysts prepared with lanthanum nitrate, aluminium nitrate and iron nitrate was investigated in catalytical syntheses of carbon nanotubes with high yields and purity. The properties of carbon nanotubes prepared by the method of CVD(chemical vapor deposition) with n-hexane as the carbon resource were studied and it was shown that the diameter of carbon nanotubes can be controlled by the molar ratio of iron to aluminum in the catalysts and that the diameter of carbon nanotubes changes a little with the decrease of the iron content in the catalysts. From the TEM pictures of carbon nanotubes, it can be found that the LaAl 1-xFe xO 3 catalysts have a significant influence on the wall thickness of the carbon nanotubes, whereas they have little influence on the inner diameter of the carbon nanotubes. 展开更多
关键词 carbon nanotube LaAl1-xFexO3 Chemical vapor deposition Diameter controlled catalyst
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Growth of carbon nanotubes on the novel FeCo-Al_2O_3 catalyst prepared by ultrasonic coprecipitation 被引量:2
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作者 Jie Wen Wei Chu +1 位作者 Chengfa Jiang Dongge Tong 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2010年第2期156-160,共5页
FeCo-Al2O3 catalyst was prepared by an ultrasonic coprecipitation (UC) method for the growth of carbon nanotubes (CNTs) from catalytic decomposition of methane.Its catalytic performance was compared with that of t... FeCo-Al2O3 catalyst was prepared by an ultrasonic coprecipitation (UC) method for the growth of carbon nanotubes (CNTs) from catalytic decomposition of methane.Its catalytic performance was compared with that of the FeCo-Al2O3 catalyst counterparts prepared by stepwise impregnation (I) and conventional coprecipitation (C) methods,respectively.The structure and properties of the catalysts and the CNTs as produced thereon were investigated by means of XRD,XPS,TEM and N2 adsorption techniques.It was found that the catalyst prepared by the ultrasonic coprecipitation method was more active,and the yield and purity of the synthesized CNTs were promoted evidently.The XPS results revealed that there were more active components on the surface of the catalyst prepared by the ultrasonic coprecipitation method.On the other hand,N2 adsorption demonstrated that the catalyst prepared by the ultrasonic coprecipitation method conferred larger specific surface area,which was beneficial to dispersion of active components.TEM images further confirmed its higher dispersion.These factors could be responsible for its higher activity for the growth of CNTs from catalytic decomposition of methane. 展开更多
关键词 carbon nanotubes ultrasonic coprecipitation FeCo-Al2O3 catalyst chemical vapor deposition (CVD)
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Platelet carbon nanofibers as support of Pt-CoO electrocatalyst for superior hydrogen evolution 被引量:2
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作者 Jie Gan Zikun Huang +5 位作者 Wei Luo Wenyao Chen Yueqiang Cao Gang Qian Xinggui Zhou Xuezhi Duan 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2021年第1期33-40,I0002,共9页
Exploration of cost-effective Pt/C catalysts has been a significant issue for electrochemical hydrogen evolution reaction(HER) toward sustainable energy conversion and storage.Herein,we report a fabrication strategy b... Exploration of cost-effective Pt/C catalysts has been a significant issue for electrochemical hydrogen evolution reaction(HER) toward sustainable energy conversion and storage.Herein,we report a fabrication strategy by employing platelet carbon nanofibers(p-CNF) as the support to immobilize Pt-CoO HER electrocatalyst using atomic layer deposition method.The edge-rich p-CNF support is found to act as the anchoring sites of Pt nanoparticles and favorably capture electrons from Pt to yield electron-deficient Pt surfaces for the boosted HER.Additionally,the sequential growth of CoO onto the Pt/p-CNF catalyst elaborately constructs the Pt-CoO interface and facilitates the electron transfer from Pt to CoO,which further enhances the HER activity.These advantages endow the fabricated Pt-CoO/p-CNF catalyst with the superior HER activity,e.g.,a very low overpotential of 26 mV at the current density of 10 mA·cm-2 and a mass activity of 4.42 A·mgPt-1at the overpotential of 30 mV,18.8 times higher than that of the commercial20 wt% Pt/C catalyst.The insights reported here could shed light on for the fabrication of cost-effective Pt-based composite HER catalysts. 展开更多
关键词 Hydrogen evolution ELECTROcatalystS Platelet carbon nanofibers Pt-CoO catalyst Atomic layer deposition
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Highly selective synthesis of single-walled carbon nanotubes from methane in a coupled Downer-turbulent fluidized-bed reactor 被引量:1
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作者 Song Yun Weizhong Qian +5 位作者 Chaojie Cui Yuntao Yu Chao Zheng Yi Liu Qiang Zhang Fei Wei 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2013年第4期567-572,共6页
For the synthesis of single-walled carbon nanotubes (SWCNTs) from CH4 over a Fe/MgO catalyst, we proposed a coupled Downer-turbulent fluidized-bed (TFB) reactor to enhance the selectivity and yield (or production... For the synthesis of single-walled carbon nanotubes (SWCNTs) from CH4 over a Fe/MgO catalyst, we proposed a coupled Downer-turbulent fluidized-bed (TFB) reactor to enhance the selectivity and yield (or production rate) of SWCNTs. By controlling a very short catalyst residence time (1-3 s) in the Downer, only part of Fe oxides can be reduced to form Fe nano particles (NPs) available for the growth of SWCNTs. The percentage of unreduced Fe oxides increased and the yield of SWCNTs decreased accordingly with the increase of catalyst feeding rate in Downer. SWCNTs were preferentially grown on the catalyst surface and inhibited the sintering of the Fe crystallites which would be formed thereafter in the downstream TFB, evidenced by TEM, Raman and TGA. The coupled Downer-turbulent fluidized-bed reactor technology allowed higher selectivity and higher production rate of SWCNTs as compared to TFB alone. 展开更多
关键词 carbon nanotube chemical vapor deposition METHANE FLUIDIZED-BED catalyst
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Controlling the Diameter of Single-Walled Carbon Nanotubes by Improving the Dispersion of the Uniform Catalyst Nanoparticles on Substrate 被引量:1
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作者 Junjun Chen Xiangju Xu +1 位作者 Lijie Zhang Shaoming Huang 《Nano-Micro Letters》 SCIE EI CAS 2015年第4期353-359,共7页
To have uniform nanoparticles individually dispersed on substrate before single-walled carbon nanotubes(SWNTs)growth at high temperature is the key for controlling the diameter of the SWNTs.In this letter,a facile app... To have uniform nanoparticles individually dispersed on substrate before single-walled carbon nanotubes(SWNTs)growth at high temperature is the key for controlling the diameter of the SWNTs.In this letter,a facile approach to control the diameter and distribution of the SWNTs by improving the dispersion of the uniform Fe/Mo nanoparticles on silicon wafers with silica layer chemically modified by 1,1,1,3,3,3-hexamethyldisilazane under different conditions is reported.It is found that the dispersion of the catalyst nanoparticles on Si wafer surface can be improved greatly from hydrophilic to hydrophobic,and the diameter and distribution of the SWNTs depend strongly on the dispersion of the catalyst on the substrate surface.Well dispersion of the catalyst results in relatively smaller diameter and narrower distribution of the SWNTs due to the decrease of aggregation and enhancement of dispersion of the catalyst nanoparticles before growth.It is also found that the diameter of the superlong aligned SWNTs is smaller with more narrow distribution than that of random nanotubes. 展开更多
关键词 Single-walled carbon nanotube Diameter control Chemical modification Chemical vapor deposition catalyst nanoparticles
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Growth of straight carbon nanotubes by simple thermal chemical vapor deposition 被引量:1
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作者 邹小平 H.ABE +4 位作者 T.SHIMIZU A.ANDO H.TOKUMOTO 朱申敏 周豪慎 《中国有色金属学会会刊:英文版》 CSCD 2006年第B02期689-691,共3页
Straight carbon nanotubes (CNTs) were achieved by simple thermal chemical vapor deposition(STCVD) catalyzed by Mo-Fe alloy catalyst on silica supporting substrate at 700℃. High-resolution transmission electron micros... Straight carbon nanotubes (CNTs) were achieved by simple thermal chemical vapor deposition(STCVD) catalyzed by Mo-Fe alloy catalyst on silica supporting substrate at 700℃. High-resolution transmission electron microscopy images show that the straight CNTs are well graphitized with no attached amorphous carbon. Mo-Fe alloy catalyst particles play a very crucial role in the growth of straight CNTs. The straight carbon nanotubes contain much less defects than the curved nanotubes and might have potential applications for nanoelectrical devices in the future. The simple synthesis of straight CNTs may have benefit for large-scale productions. 展开更多
关键词 碳纳米管 直管 生长 简易热化学汽相沉积 Mo-Fe合金催化剂
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Growth of Aligned Carbon Nanotubes on Large Scale by Methane Decomposition with Deactivation Inhibitor
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作者 Hao Yu Zhili Li Cheng Zhang Feng Peng Hongjuan Wang 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2007年第4期382-388,共7页
The effects of additives containing iron or nickel during chemical vapor deposition (CVD) on the growth of carbon nanotubes (CNTs) by methane decomposition on Mo/MgO catalyst were investigated. Ferrocene and nicke... The effects of additives containing iron or nickel during chemical vapor deposition (CVD) on the growth of carbon nanotubes (CNTs) by methane decomposition on Mo/MgO catalyst were investigated. Ferrocene and nickel nitrate were introduced as deactivation inhibitors by in-situ evaporation during CVD. The precisely controlled in-situ introduction of these inhibitors increased the surface renewal of catalyst, and therefore prevented the catalyst from deactivation. Using this method, aligned multi-walled CNTs with parallel mesopores can be produced on a large scale. 展开更多
关键词 aligned carbon nanotubes chemical vapor deposition DEACTIVATION INHIBItoR methane decomposition Mo/MgO catalyst FERROCENE nickel nitrate
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In situ carbon nanotube synthesis by the reduction of NiO/γ-Al_2O_3 catalyst in methane
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作者 Dongyan Xu Haizhen Wang Qingjie Guo 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2010年第6期617-621,共5页
The synthesis of carbon nanotubes (CNTs) via chemical vapour deposition of methane on NiO/γ-Al2O3 catalyst has been investigated.The reduction behavior of NiO/γ-Al2O3 by methane was studied using thermogravimetric... The synthesis of carbon nanotubes (CNTs) via chemical vapour deposition of methane on NiO/γ-Al2O3 catalyst has been investigated.The reduction behavior of NiO/γ-Al2O3 by methane was studied using thermogravimetric (TG) and X-ray diffraction (XRD) techniques.It was found that the NiO supported on γ-Al2O3,was reduced to Ni0 in methane atmosphere in the temperature range of 710-770℃.The catalytic activity of NiO/γ-Al2O3 for CNTs synthesis by in situ chemical vapour deposition of methane during the reduction was also investigated.Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the CNTs produced at various reduction temperatures.The results indicated that the reduction temperature exhibits obvious influence on the morphology and the yield of CNTs.CNTs with the diameter of about 20 nm were obtained at reduction temperature of 750℃,and higher reduction temperature (such as 800 and 850℃) led to an increase in CNTs diameter and a decrease in CNTs yield. 展开更多
关键词 chemical vapour deposition carbon nanotubes NiO/γ-Al2O3 catalyst reduction temperature
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Influence of Deposition Temperature on the Electrical and Electrochemical Properties of Carbon-Based Coatings for Metallic Bipolar Plates, Prepared by Cathodic Arc Evaporation
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作者 Maximilian Steinhorst Maurizio Giorgio +1 位作者 Teja Roch Christoph Leyens 《Advances in Materials Physics and Chemistry》 2022年第4期47-57,共11页
Cathodic arc evaporation is a well-established physical vapor deposition technique which is characterized by a high degree of ionization and high deposition rate. So far, this technique has been mainly used for the de... Cathodic arc evaporation is a well-established physical vapor deposition technique which is characterized by a high degree of ionization and high deposition rate. So far, this technique has been mainly used for the deposition of tribological coatings. In this study, anti-corrosive and electrical conductive carbon-based coatings with a metallic interlayer were prepared on stainless steel substrates as surface modification for metallic bipolar plates. Hereby, the influence of the deposition temperature during the deposition of the carbon top layer was investigated. Raman spectroscopy revealed differences in the microstructure at 200°C compared to 300°C and 100°C. Measurements of the interfacial contact resistance showed that the deposited coatings significantly improve the electrical conductivity. There are only minor differences between the different carbon top layers. The corrosion resistance of the coatings was studied via potentiodynamic polarization at room temperature and 80°C. Experiments showed that the coating with a carbon top layer deposited at 200°C, considerably reduces the current density and thus corrosion of the substrate is suppressed. 展开更多
关键词 Bipolar Plate CORROSION Interfacial Contact resistance carbon Thin Film Physical Vapor deposition
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Effect of CeO_(2) on carbon deposition resistance of Ni/CeO_(2) catalyst supported on SiC porous ceramic for ethanol steam reforming 被引量:2
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作者 Tingting Bao Hui zhou +6 位作者 Yi Zhang Chenxu Guo Wenming Guo Hang Qin Pengzhao Gao Hanning Xiao Weixiong Liu 《Journal of Rare Earths》 SCIE EI CAS CSCD 2023年第11期1703-1713,I0002,共12页
Ni/CeO_(2) catalysts(nCeO_(2):n_(Ni)=0,1,4,7,10)supported on SiC porous ce ramics for ethanol steam reforming(ESR)were investigated with respect to hydrogen production performance and growth of carbon deposition.The o... Ni/CeO_(2) catalysts(nCeO_(2):n_(Ni)=0,1,4,7,10)supported on SiC porous ce ramics for ethanol steam reforming(ESR)were investigated with respect to hydrogen production performance and growth of carbon deposition.The oxygen released from CeO_(2) enables the oxidation of CH_(x) species to serve as carbon precursors,thus providing Ni/CeO_(2) catalysts with stronger resistance to carbon deposition compared with Ni catalysts.The Ni/CeO_(2) catalysts prepared by inverse microemulsion and impregnation methods exhibit regular semicircular spherical shape on SiC porous ceramics.Under 500℃for 25 h of ESR reaction,the ethanol conversion rate over Ni/CeO_(2) catalysts(n_(CeO_(2)):n_(Ni)=7)is sustained up to 100%and H_(2) selectivity is essentially kept at 74%.The by-product selectivity declines stepwise with increasing content of CeO_(2),which is attributed to the adsorption and oxidation of CO and of CH_(x) species as CH_4 precursor from CeO_(2).The scanning electron microscopy(SEM)and transform electron microscopy(TEM)results reveal that further loading of CeO_(2) on the surface of Ni catalysts can alleviate both migration and sintering of Ni particles.Furthermore,carbon deposition on Ni/CeO_(2) catalysts preferentially outgrow filamentous rather than amorphous carbon,with a tendency for the latter to be more deactivated. 展开更多
关键词 SiC porous CERAMIC Ni/CeO_(2)catalyst carbon deposition Ethanol steam reforming Rare earths
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Catalytic wet oxidation of aniline over Ru catalysts supported on a modified TiO_2 被引量:11
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作者 宋明光 王筠松 +4 位作者 郭耘 王丽 詹望成 郭杨龙 卢冠忠 《Chinese Journal of Catalysis》 CSCD 北大核心 2017年第7期1155-1165,共11页
The catalytic wet air oxidation of aniline over Ru catalysts supported on modified Ti 2 (Ti 2, Ti0.9Ce0.1O2, Ti0.9Zr0.1O2) is investigated. A series of characterization techniques are conducted to deter... The catalytic wet air oxidation of aniline over Ru catalysts supported on modified Ti 2 (Ti 2, Ti0.9Ce0.1O2, Ti0.9Zr0.1O2) is investigated. A series of characterization techniques are conducted to determine the relationship between the physico-chemical properties and the catalytic performance. As a result of the good metal dispersion and large number of surface oxygen species, the Ru/Ti0.9 Zr0.1O2 catalyst presents the best catalytic activity among the tested samples. The effects of the operating conditions on the reaction are investigated and the optimal reaction conditions are determined. Based on the relationship between the by-products concentration and the reaction time, the reaction path for the catalytic oxidation of aniline is established. Carbonaceous deposits on the surface of the support are known to be the main reason for catalyst deactivation. The catalysts maintain a constant activity even after three consecutive cycles. 展开更多
关键词 catalystic wet air oxidation PHYSICO-CHEMICAL Aniline removal carbon deposites
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Promotion Effects of Ceria on Fischer-Tropsch Synthesis Performance of Co/Al_2O_3 Catalyst
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作者 代小平 余长春 沈师孔 《Petroleum Science》 SCIE CAS CSCD 2004年第3期82-86,共5页
The addition of small amounts of ceria to Co/Al2O3 catalysts increases the turnover rate of the catalyst and C5+ selectivity in the Fischer-Tropsch synthesis. In this work, the amounts of ceria, the calcination tempe... The addition of small amounts of ceria to Co/Al2O3 catalysts increases the turnover rate of the catalyst and C5+ selectivity in the Fischer-Tropsch synthesis. In this work, the amounts of ceria, the calcination temperature, the temperature-programmed reduction (TPR), the temperature-programmed oxidation (TPO), and XRD are investigated. The results show that the addition of small amounts of ceria to Co/Al2O3 catalyst (Ce/Co≈1∶ 10 ~1∶ 7, atom) can increase the CO conversion and liquid yield, while the calcination temperature can control both the chain growth probability and CO conversion in a reverse trend. The TPR and TPO experiments show that small amounts of Ceria can improve the reducibility, but the amounts of carbon deposit increase, and two-type carbon deposition is found in the short-term reaction catalyst. 展开更多
关键词 Fischer-Tropsch synthesis cobalt catalyst ALUMINA CERIUM TP carbon deposition
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Ni/Al_2O_3 catalysts for CO methanation: Effect of Al_2O_3 supports calcined at different temperatures 被引量:18
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作者 Jiajian Gao Chunmiao Jia +5 位作者 Jing Li Meiju Zhang Fangna Gu Guangwen Xu Ziyi Zhong Fabing Su 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2013年第6期919-927,共9页
The correlation between phase structures and surface acidity of Al2O3 supports calcined at different temperatures and the catalytic performance of Ni/Al2O3 catalysts in the production of synthetic natural gas(SNG) via... The correlation between phase structures and surface acidity of Al2O3 supports calcined at different temperatures and the catalytic performance of Ni/Al2O3 catalysts in the production of synthetic natural gas(SNG) via CO methanation was systematically investigated. A series of 10 wt% NiO/Al2O3 catalysts were prepared by the conventional impregnation method, and the phase structures and surface acidity of Al2O3 supports were adjusted by calcining the commercial γ-Al2O3 at different temperatures(600–1200 C). CO methanation reaction was carried out in the temperature range of 300–600 C at different weight hourly space velocities(WHSV = 30000 and 120000 mL·g-1h-1) and pressures(0.1 and 3.0 MPa). It was found that high calcination temperature not only led to the growth in Ni particle size, but also weakened the interaction between Ni nanoparticles and Al2O3 supports due to the rapid decrease of the specific surface area and acidity of Al2O3 supports. Interestingly, Ni catalysts supported on Al2O3 calcined at 1200 C(Ni/Al2O3-1200) exhibited the best catalytic activity for CO methanation under different reaction conditions. Lifetime reaction tests also indicated that Ni/Al2O3-1200 was the most active and stable catalyst compared with the other three catalysts, whose supports were calcined at lower temperatures(600, 800 and 1000 C). These findings would therefore be helpful to develop Ni/Al2O3 methanation catalyst for SNG production. 展开更多
关键词 Ni catalyst ALUMINA CO methanation synthetic natural gas carbon deposition
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Correlation of Deactivation of Ni-Mo-W/Al2O3 during Ultra-Low-Sulfur Diesel Production with Surface Carbon Species 被引量:6
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作者 Ge Panzhu Zhang Le +2 位作者 Ding Shi Li Dadong Nie Hong 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2017年第2期1-7,共7页
The deactivation of a Ni-Mo-W/Al_2O_3 catalyst during ultra-low-sulfur diesel production was investigated in a pilot plant. The reasons of catalyst deactivation were analyzed by the methods of elemental analysis, BET ... The deactivation of a Ni-Mo-W/Al_2O_3 catalyst during ultra-low-sulfur diesel production was investigated in a pilot plant. The reasons of catalyst deactivation were analyzed by the methods of elemental analysis, BET and TG-MS. The results showed that the catalyst deactivation rate was notable at the beginning of run, and then gradually reached a steady state after 448 h. In the initial period the catalyst deactivation may mainly be caused by the formation of the carbon deposits. The carbon deposits blocked the catalyst pores and the accessibility of active center decreased. The TG-MS analysis identified three types of carbon species deposited on the catalysts, viz.: the low temperature carbon deposit with high H/C atomic ratio, the medium temperature carbon deposit, and the high temperature carbon with low H/C atomic ratio. The amount of high temperature carbon deposits on the catalyst determined the overall activity and, therefore the high temperature carbon was a major contributor to the deactivation of Ni-Mo-W catalyst. 展开更多
关键词 ultra-low-sulfur DIESEL carbon deposit catalyst DEACTIVATION catalyst SPECIES
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