Integrated CO_(2)capture and utilization(ICCU)technology requires dual functional materials(DFMs)to carry out the process in a single reaction system.The influence of the calcination atmosphere on efficiency of 4%Ru-8...Integrated CO_(2)capture and utilization(ICCU)technology requires dual functional materials(DFMs)to carry out the process in a single reaction system.The influence of the calcination atmosphere on efficiency of 4%Ru-8%Na_(2)CO_(3)-8%CaO/γ-Al_(2)O_(3)DFM is studied.The adsorbent precursors are first co-impregnated onto alumina and calcined in air.Then,Ru precursor is impregnated and four aliquotes are subjected to different calcination protocols:static air in muffle or under different mixtures(10%H_(2)/N_(2),50%H_(2)/N_(2)and N_(2))streams.Samples are characterized by XRD,N_(2)adsorption-desorption,H_(2)chemisorption,TEM,XPS,H_(2)-TPD,H_(2)-TPR,CO_(2)-TPD and TPSR.The catalytic behavior is evaluated,in cycles of CO_(2)adsorption and hydrogenation to CH_(4),and temporal evolution of reactants and products concentrations is analyzed.The calcination atmosphere influences the physicochemical properties and,ultimately,activity of DFMs.Characterization data and catalytic performance discover the acccomodation of Ru nanoparticles disposition and basic sites is mostly influencing the catalytic activity.DFM calcined under N_(2)flow(RuNaCa-N_(2))shows the highest CH_(4)production(449μmol/g at 370℃),because a well-controlled decomposition of precursors which favors the better accomodation of adsorbent and Ru phases,maximizing the specific surface area,the Ru-basic sites interface and the participation of different basic sites in the CO_(2)methanation reaction.Thus,the calcination in a N_(2)flow is revealed as the optimal calcination protocol to achieve highly efficient DFM for integrated CO_(2)adsorption and hydrogenation applications.展开更多
The phase composition, phase transition and phase structure transformation of the wire-cut section of functionally graded WC-Co cemented carbide with dual phase structure were investigated by XRD phase analysis. It is...The phase composition, phase transition and phase structure transformation of the wire-cut section of functionally graded WC-Co cemented carbide with dual phase structure were investigated by XRD phase analysis. It is shown that the composition of η phase in the core zone is Co_3W_3C (M_6 C type). The structure of cobalt based solid solution binder phase is fcc type. At the cooling stage of the sintering process, the phase transition of η phase, i.e. M_6C→M_12C and the martensitic phase transition of the cobalt based solid solution binder phase, i.e. fcc→hcp are suppressed, which facilitates the strengthening of the alloy. Because the instantaneous temperature of the discharge channel is as high as 10 000 ℃ during the wire cutting process, the processed surface is oxidized. Nevertheless, the oxide layer thickness is in micro grade. In the oxide film, η phase is decomposed into W_2C and CoO, and cobalt based solid solution binder is selectively oxidized, while WC remains stable due to the existence of carbon containing liquid organic cutting medium.展开更多
The behavior of two parallel symmetry permeable cracks in functionally graded piezoelectric materials subjected to an anti-plane shear loading was investigated. To make the analysis tractable, it was assumed that the ...The behavior of two parallel symmetry permeable cracks in functionally graded piezoelectric materials subjected to an anti-plane shear loading was investigated. To make the analysis tractable, it was assumed that the material properties varied exponentially with coordinate vertical to the crack. By using the Fourier transform, the problem could be solved with the help of two pairs of dual integral equations, in which the unknown variables were the jumps of the displacements across the crack surfaces. To solve the dual integral equations, the displacement on the crack surfaces was expanded in a series of Jacobi polynomials. The normalized stress and electrical displacement intensity factors were determined for different geometric and property parameters for permeable electric boundary conditions. Numerical examples were provided to show the effect of the geometry of the interacting cracks and the functionally graded material parameter upon the stress intensity factors of cracks.展开更多
开发与应用CO_(2)捕集-加氢转化一体化技术是应对当前全球气候变化危机、实现“双碳”目标的重要途径之一。其中具有吸附和催化组分的双功能材料研发与优化是技术核心。系统总结了国内外主要科研机构对应用于CO_(2)捕集原位甲烷化和原...开发与应用CO_(2)捕集-加氢转化一体化技术是应对当前全球气候变化危机、实现“双碳”目标的重要途径之一。其中具有吸附和催化组分的双功能材料研发与优化是技术核心。系统总结了国内外主要科研机构对应用于CO_(2)捕集原位甲烷化和原位逆水煤气变换这2类主要CO_(2)捕集-加氢转化一体化技术双功能材料的主要工作,包括合成方法、吸附性能、反应动力学、促进机理、失活机理和应用模式等方面,并详细介绍了国内外主要科研机构在CO_(2)捕集-加氢转化一体化方面取得的最新进展。DFM是兼具催化和吸附组分的复合材料,在催化组分选择上,贵金属催化剂虽然活性高,但成本昂贵,Ni基催化剂成本较低,但还原性较差、在含氧气氛下易失活;在吸附组分选择上,金属氧化物(如CaO、MgO)和碱金属碳酸盐(如Na 2 CO 3、K 2 CO 3)是具有潜力的吸附组分,特别是MgO和CaO因其理论吸附量高而被视为最有前景的吸附组分,尽管面临实际吸附量不理想和循环稳定性差的挑战。目前研究主要通过碱金属熔盐掺杂提升MgO实际吸附量,通过掺杂金属助剂(如La、Co、Fe等)提高CaO吸附剂的循环性能和抗烧结能力。动力学研究表明反应速率高度依赖于H 2分压,通过调节吸附和催化的时间可提高CH 4平均产量。ICCU技术展现出广阔的应用前景,尤其是在钢铁、能源、化工等关键领域。然而,全面评估技术的环境影响,特别是从生命周期评估(LCA)角度,对于全面理解ICCU技术的环境可持续性及其在碳减排中的贡献至关重要。未来,通过持续研究和技术创新,解决现有挑战,ICCU技术有望在工业化应用中取得显著成果,为全球碳减排做出重要贡献。展开更多
基金supported by Ministry of Science and InnovationNational Research Agency(Project PID2019-105960RBC21)+1 种基金by the Basque Government(Project IT1509-2022)One of the authors(JAOC)acknowledges the post-doctoral research grant(DOCREC20/49)provided by the University of the Basque Country。
文摘Integrated CO_(2)capture and utilization(ICCU)technology requires dual functional materials(DFMs)to carry out the process in a single reaction system.The influence of the calcination atmosphere on efficiency of 4%Ru-8%Na_(2)CO_(3)-8%CaO/γ-Al_(2)O_(3)DFM is studied.The adsorbent precursors are first co-impregnated onto alumina and calcined in air.Then,Ru precursor is impregnated and four aliquotes are subjected to different calcination protocols:static air in muffle or under different mixtures(10%H_(2)/N_(2),50%H_(2)/N_(2)and N_(2))streams.Samples are characterized by XRD,N_(2)adsorption-desorption,H_(2)chemisorption,TEM,XPS,H_(2)-TPD,H_(2)-TPR,CO_(2)-TPD and TPSR.The catalytic behavior is evaluated,in cycles of CO_(2)adsorption and hydrogenation to CH_(4),and temporal evolution of reactants and products concentrations is analyzed.The calcination atmosphere influences the physicochemical properties and,ultimately,activity of DFMs.Characterization data and catalytic performance discover the acccomodation of Ru nanoparticles disposition and basic sites is mostly influencing the catalytic activity.DFM calcined under N_(2)flow(RuNaCa-N_(2))shows the highest CH_(4)production(449μmol/g at 370℃),because a well-controlled decomposition of precursors which favors the better accomodation of adsorbent and Ru phases,maximizing the specific surface area,the Ru-basic sites interface and the participation of different basic sites in the CO_(2)methanation reaction.Thus,the calcination in a N_(2)flow is revealed as the optimal calcination protocol to achieve highly efficient DFM for integrated CO_(2)adsorption and hydrogenation applications.
基金Projects(50323008, 50574104) supported by the National Natural Science Foundation of ChinaProject (04JJ3084) supported by the Natural Science Foundation of Hunan Province, China
文摘The phase composition, phase transition and phase structure transformation of the wire-cut section of functionally graded WC-Co cemented carbide with dual phase structure were investigated by XRD phase analysis. It is shown that the composition of η phase in the core zone is Co_3W_3C (M_6 C type). The structure of cobalt based solid solution binder phase is fcc type. At the cooling stage of the sintering process, the phase transition of η phase, i.e. M_6C→M_12C and the martensitic phase transition of the cobalt based solid solution binder phase, i.e. fcc→hcp are suppressed, which facilitates the strengthening of the alloy. Because the instantaneous temperature of the discharge channel is as high as 10 000 ℃ during the wire cutting process, the processed surface is oxidized. Nevertheless, the oxide layer thickness is in micro grade. In the oxide film, η phase is decomposed into W_2C and CoO, and cobalt based solid solution binder is selectively oxidized, while WC remains stable due to the existence of carbon containing liquid organic cutting medium.
基金Sponsred by the Natural Science Foundation with Excellent Young Investigators of Heilongjiang Province(Grant No.JC04 -08)the Natural Science Foundation of Heilongjiang Province(Grant No.A0301)+1 种基金the National Science Foundation with Excellent Young Investigators (Grant No.10325208)the National Natural Science Key Item Foundation of China (Grant No.10432030).
文摘The behavior of two parallel symmetry permeable cracks in functionally graded piezoelectric materials subjected to an anti-plane shear loading was investigated. To make the analysis tractable, it was assumed that the material properties varied exponentially with coordinate vertical to the crack. By using the Fourier transform, the problem could be solved with the help of two pairs of dual integral equations, in which the unknown variables were the jumps of the displacements across the crack surfaces. To solve the dual integral equations, the displacement on the crack surfaces was expanded in a series of Jacobi polynomials. The normalized stress and electrical displacement intensity factors were determined for different geometric and property parameters for permeable electric boundary conditions. Numerical examples were provided to show the effect of the geometry of the interacting cracks and the functionally graded material parameter upon the stress intensity factors of cracks.
文摘开发与应用CO_(2)捕集-加氢转化一体化技术是应对当前全球气候变化危机、实现“双碳”目标的重要途径之一。其中具有吸附和催化组分的双功能材料研发与优化是技术核心。系统总结了国内外主要科研机构对应用于CO_(2)捕集原位甲烷化和原位逆水煤气变换这2类主要CO_(2)捕集-加氢转化一体化技术双功能材料的主要工作,包括合成方法、吸附性能、反应动力学、促进机理、失活机理和应用模式等方面,并详细介绍了国内外主要科研机构在CO_(2)捕集-加氢转化一体化方面取得的最新进展。DFM是兼具催化和吸附组分的复合材料,在催化组分选择上,贵金属催化剂虽然活性高,但成本昂贵,Ni基催化剂成本较低,但还原性较差、在含氧气氛下易失活;在吸附组分选择上,金属氧化物(如CaO、MgO)和碱金属碳酸盐(如Na 2 CO 3、K 2 CO 3)是具有潜力的吸附组分,特别是MgO和CaO因其理论吸附量高而被视为最有前景的吸附组分,尽管面临实际吸附量不理想和循环稳定性差的挑战。目前研究主要通过碱金属熔盐掺杂提升MgO实际吸附量,通过掺杂金属助剂(如La、Co、Fe等)提高CaO吸附剂的循环性能和抗烧结能力。动力学研究表明反应速率高度依赖于H 2分压,通过调节吸附和催化的时间可提高CH 4平均产量。ICCU技术展现出广阔的应用前景,尤其是在钢铁、能源、化工等关键领域。然而,全面评估技术的环境影响,特别是从生命周期评估(LCA)角度,对于全面理解ICCU技术的环境可持续性及其在碳减排中的贡献至关重要。未来,通过持续研究和技术创新,解决现有挑战,ICCU技术有望在工业化应用中取得显著成果,为全球碳减排做出重要贡献。
