A series of carbon nanotubes-supported K-Co-Mo catalysts were prepared by a sol-gel method combined with incipient wetness impregnation. The catalyst structures were characterized by X-ray diffraction, N2 adsorption-d...A series of carbon nanotubes-supported K-Co-Mo catalysts were prepared by a sol-gel method combined with incipient wetness impregnation. The catalyst structures were characterized by X-ray diffraction, N2 adsorption-desorption, transmission electron microscopy and H2-TPD, and its catalytic performance toward the synthesis of higher alcohols from syngas was investigated. The as-prepared catalyst particles had a low crystallization degree and high dispersion on the outer and inner surface of CNTs. The uniform mesoporous structure of CNTs increased the diffusion rate of reactants and products, thus promoting the reaction conversion. Furthermore, the incorporation of CNTs support led to a high capability of hydrogen absorption and spillover and promoted the formation of alkyl group, which served as the key intermediate for the alcohol formation and carbon chain growth. Benefiting from these characteristics, the CNTs supported Mo-based catalyst showed the excellent catalytic performance for the higher alcohols synthesis as compared to the unsupported catalyst and activated carbon supported catalyst.展开更多
Activated carbon supported Mo-based catalysts were prepared and reduced under different activation atmospheres, including pure H2, syngas （H2/CO=2/1）, and pure CO. The cat- alysts structures were characterized by X-...Activated carbon supported Mo-based catalysts were prepared and reduced under different activation atmospheres, including pure H2, syngas （H2/CO=2/1）, and pure CO. The cat- alysts structures were characterized by X-ray diffraction , X-ray absorption fine structure, and in situ diffuse reflectance infrared Fourier transform spectroscopy. The catalytic per- formance for the higher alcohol synthesis from syngas was tested. The pure H2 treatment showed a high reduction capacity. The presence of a large amount of metallic CoO and low valence state Mo^φ＋ （0〈φ〈2） on the surface suggested a super activity for the CO dissoci- ation and hydrogenation, which promoted hydrocarbons formation and reduced the alcohol selectivity. In contrast, the pure CO-reduced catalyst had a low reduction degree. The Mo and Co species at the catalyst mainly existed in the form of Mo^4＋ and Co^2＋. The syngas- reduced catalyst showed the highest activity and selectivity for the higher alcohols synthesis. We suggest that the syngas treatment had an appropriate reduction capacity that is between those of pure H2 and pure CO and led to the coexistence of multivalent Co species as well as the enrichment of Mo~＋ on the catalyst＇s surface. The synergistic effects between these active species provided a better cooperativity and equilibrium between the CO dissociation, hydrogenation and CO insertion and thus contributed beneficially to the formation of higher alcohols.展开更多
2012 年至今,我国集成电路企业逐步从高速增长向高质量发展阶段转变,产业结构不断升级,涌现了一批核心技术企业。但是,即使许多中国集成电路企业已经实施了 ISO9001,仍无法与欧美和日韩竞争。建立了多元线性回归模型,探索了 ISO 9001 ...2012 年至今,我国集成电路企业逐步从高速增长向高质量发展阶段转变,产业结构不断升级,涌现了一批核心技术企业。但是,即使许多中国集成电路企业已经实施了 ISO9001,仍无法与欧美和日韩竞争。建立了多元线性回归模型,探索了 ISO 9001 与我国集成电路企业的非财务绩效和财务绩效之间的关系。并指出了该模型存在的局限性和下一步改进方向,对于集成电路企业的短期绩效提升和长期可持续发展具有重要意义。基于多元回归探索 ISO 9001 与集成电路展开更多
基金This work was supported by National Natural Science Foundation of China （No.21673214）.
文摘A series of carbon nanotubes-supported K-Co-Mo catalysts were prepared by a sol-gel method combined with incipient wetness impregnation. The catalyst structures were characterized by X-ray diffraction, N2 adsorption-desorption, transmission electron microscopy and H2-TPD, and its catalytic performance toward the synthesis of higher alcohols from syngas was investigated. The as-prepared catalyst particles had a low crystallization degree and high dispersion on the outer and inner surface of CNTs. The uniform mesoporous structure of CNTs increased the diffusion rate of reactants and products, thus promoting the reaction conversion. Furthermore, the incorporation of CNTs support led to a high capability of hydrogen absorption and spillover and promoted the formation of alkyl group, which served as the key intermediate for the alcohol formation and carbon chain growth. Benefiting from these characteristics, the CNTs supported Mo-based catalyst showed the excellent catalytic performance for the higher alcohols synthesis as compared to the unsupported catalyst and activated carbon supported catalyst.
文摘Activated carbon supported Mo-based catalysts were prepared and reduced under different activation atmospheres, including pure H2, syngas （H2/CO=2/1）, and pure CO. The cat- alysts structures were characterized by X-ray diffraction , X-ray absorption fine structure, and in situ diffuse reflectance infrared Fourier transform spectroscopy. The catalytic per- formance for the higher alcohol synthesis from syngas was tested. The pure H2 treatment showed a high reduction capacity. The presence of a large amount of metallic CoO and low valence state Mo^φ＋ （0〈φ〈2） on the surface suggested a super activity for the CO dissoci- ation and hydrogenation, which promoted hydrocarbons formation and reduced the alcohol selectivity. In contrast, the pure CO-reduced catalyst had a low reduction degree. The Mo and Co species at the catalyst mainly existed in the form of Mo^4＋ and Co^2＋. The syngas- reduced catalyst showed the highest activity and selectivity for the higher alcohols synthesis. We suggest that the syngas treatment had an appropriate reduction capacity that is between those of pure H2 and pure CO and led to the coexistence of multivalent Co species as well as the enrichment of Mo~＋ on the catalyst＇s surface. The synergistic effects between these active species provided a better cooperativity and equilibrium between the CO dissociation, hydrogenation and CO insertion and thus contributed beneficially to the formation of higher alcohols.
文摘2012 年至今,我国集成电路企业逐步从高速增长向高质量发展阶段转变,产业结构不断升级,涌现了一批核心技术企业。但是,即使许多中国集成电路企业已经实施了 ISO9001,仍无法与欧美和日韩竞争。建立了多元线性回归模型,探索了 ISO 9001 与我国集成电路企业的非财务绩效和财务绩效之间的关系。并指出了该模型存在的局限性和下一步改进方向,对于集成电路企业的短期绩效提升和长期可持续发展具有重要意义。基于多元回归探索 ISO 9001 与集成电路
