用均匀沉淀法制备了片状复合氧化镍 NiMO（M = Li，Sr，Y，Fe，La）催化剂，并研究了其对乙烷氧化脱氢制乙烯的催化性能.采用 X 射线衍射（XRD）、扫描电子显微镜（SEM）、程序升温还原（H2-TPR）和程序升温脱附（O2-TPD）等方法对镍基...用均匀沉淀法制备了片状复合氧化镍 NiMO（M = Li，Sr，Y，Fe，La）催化剂，并研究了其对乙烷氧化脱氢制乙烯的催化性能.采用 X 射线衍射（XRD）、扫描电子显微镜（SEM）、程序升温还原（H2-TPR）和程序升温脱附（O2-TPD）等方法对镍基催化剂进行了表征. X 射线衍射和扫描电子显微镜检测结果表明：助剂的加入对催化剂的形貌影响不大，仍为片状结构；平均粒径为5~10 nm.程序升温还原和脱附表征结果表明：助剂 Li，Sr并未进入 NiO 晶格；而助剂 Y，Fe，La 与 Ni 之间具有相互作用，因而影响催化剂的理化性质和催化活性.其中， Fe 掺杂的片状氧化镍催化剂对乙烯的选择性和收率均有所改善，340℃时 NiFeO 催化剂上的乙烯收率可达18.2%.展开更多
LiCl-promoted superbase catalysts were found to be stable and highly selective to ethene for oxidative dehydrogenation of ethane,giving 84%ethane conversion and 74%ethene yield at 923 K.Results indicated that the stro...LiCl-promoted superbase catalysts were found to be stable and highly selective to ethene for oxidative dehydrogenation of ethane,giving 84%ethane conversion and 74%ethene yield at 923 K.Results indicated that the stronger the basicity of LiC1-based catalysts,the better the catalytic performance.展开更多
An integrated approach combining the development of an innovative catalyst and the research of a set of adequate operating conditions for the propane oxidative dehydrogenation （ODH） is described.The experimental set...An integrated approach combining the development of an innovative catalyst and the research of a set of adequate operating conditions for the propane oxidative dehydrogenation （ODH） is described.The experimental set-up,specially designed for steady-state and transient studies is presented.The preparation method,the characterization and the performances in steady-state and transient regimes of catalysts based on V2W4O194-Lindqvist isopolyanion used as a precursor and supported on alumina are reported.The influence of the preparation method of the catalyst and the role of water in the feed gas are more particularly discussed.展开更多
In the oxygen diffusion hardened condition,untreated and laser surface melted pure titanium alloy (TA4) by Nd:YAG pulsed laser,are hardened at temperatures of 650 to 700℃ with the end result being a passive,mechanica...In the oxygen diffusion hardened condition,untreated and laser surface melted pure titanium alloy (TA4) by Nd:YAG pulsed laser,are hardened at temperatures of 650 to 700℃ with the end result being a passive,mechanically stable,abrasion resistant oxide ceramic rutile surface layer.The thickness of this surface layer depends on the time,temperature,and the microstructure of the Ti substrate.This paper describes the results of x-ray diffraction analysis,scanning electron microscope (SEM),microhardness measurements,and corrosion resistance measurements of hardened pure and laser treated Ti substrate.The oxygen diffusion hardened titanium alloy after laser surface melted samples (L-TA4) had a more pronounced grain structure and significantly higher roughness values than the untreated pure TA4 (U-TA4)samples.The L-TA4 samples also exhibited at least equivalent corrosion behavior and a definite increase in surface hardness compared to the U-TA4 samples.The results of this work suggest that laser surface melting plays a key role for effective oxygen diffusion hardening at 650-700℃ for pure and laser treated pure Ti alloys.展开更多
文摘用均匀沉淀法制备了片状复合氧化镍 NiMO（M = Li，Sr，Y，Fe，La）催化剂，并研究了其对乙烷氧化脱氢制乙烯的催化性能.采用 X 射线衍射（XRD）、扫描电子显微镜（SEM）、程序升温还原（H2-TPR）和程序升温脱附（O2-TPD）等方法对镍基催化剂进行了表征. X 射线衍射和扫描电子显微镜检测结果表明：助剂的加入对催化剂的形貌影响不大，仍为片状结构；平均粒径为5~10 nm.程序升温还原和脱附表征结果表明：助剂 Li，Sr并未进入 NiO 晶格；而助剂 Y，Fe，La 与 Ni 之间具有相互作用，因而影响催化剂的理化性质和催化活性.其中， Fe 掺杂的片状氧化镍催化剂对乙烯的选择性和收率均有所改善，340℃时 NiFeO 催化剂上的乙烯收率可达18.2%.
基金supported by the Ministry of Science and Technology of China(No.2005CB221408)the Science and Technology Projects of Hunan Province(No.2007FJ4151)
文摘LiCl-promoted superbase catalysts were found to be stable and highly selective to ethene for oxidative dehydrogenation of ethane,giving 84%ethane conversion and 74%ethene yield at 923 K.Results indicated that the stronger the basicity of LiC1-based catalysts,the better the catalytic performance.
基金supported by CNRS standing for Centre National de la Recherche Scientifique (France),CAPES standing for Coordenao de Aperfeioamento de Pessoal de Nível Superior (Brazil),CNPq standing for Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brazil) and FINEP standing for Financiadora de Estudos e Projetos (Brazil)
文摘An integrated approach combining the development of an innovative catalyst and the research of a set of adequate operating conditions for the propane oxidative dehydrogenation （ODH） is described.The experimental set-up,specially designed for steady-state and transient studies is presented.The preparation method,the characterization and the performances in steady-state and transient regimes of catalysts based on V2W4O194-Lindqvist isopolyanion used as a precursor and supported on alumina are reported.The influence of the preparation method of the catalyst and the role of water in the feed gas are more particularly discussed.
基金supported by the Zhejiang Provincial Natural Science Foundation of China(No.LZ13B060004)the Program for Zhejiang Leading Team of S&T Innovation(No.2013TD07)the National Natural Science Foundation of China(No.U1362102)
基金Foundation item:National Nature Science Foundation of China(50801050)
文摘In the oxygen diffusion hardened condition,untreated and laser surface melted pure titanium alloy (TA4) by Nd:YAG pulsed laser,are hardened at temperatures of 650 to 700℃ with the end result being a passive,mechanically stable,abrasion resistant oxide ceramic rutile surface layer.The thickness of this surface layer depends on the time,temperature,and the microstructure of the Ti substrate.This paper describes the results of x-ray diffraction analysis,scanning electron microscope (SEM),microhardness measurements,and corrosion resistance measurements of hardened pure and laser treated Ti substrate.The oxygen diffusion hardened titanium alloy after laser surface melted samples (L-TA4) had a more pronounced grain structure and significantly higher roughness values than the untreated pure TA4 (U-TA4)samples.The L-TA4 samples also exhibited at least equivalent corrosion behavior and a definite increase in surface hardness compared to the U-TA4 samples.The results of this work suggest that laser surface melting plays a key role for effective oxygen diffusion hardening at 650-700℃ for pure and laser treated pure Ti alloys.
