An effective method for the regeneration of thermally deactivated commercial monolith SCR catalysts was investigated. Two types of regenerated solutions, namely NH4C1 （l mol/L） and dilute H2SO4 （0.5 tool/L）, were ...An effective method for the regeneration of thermally deactivated commercial monolith SCR catalysts was investigated. Two types of regenerated solutions, namely NH4C1 （l mol/L） and dilute H2SO4 （0.5 tool/L）, were employed to treat the used catalyst. The effects of temperature and the regeneration process on the structural and textural properties of the catalysts were determined by X-ray diffraction, scanning electron microscopy, N2 adsorption/desorption, elemental analysis and Fourier transform infrared spectroscopy. The results suggest that the anatase phase of the used catalyst is maintained after exposure to high temperatures. Some of the catalytic activity was restored after regeneration. The catalyst regenerated by aqueous NH4C1 had a higher activity than that of the catalyst treated by dilute H2SO4. The main reason is that the NH3 generated from the decomposition of NH4C1 at high temperatures can be adsorbed onto the catalyst which promotes the reaction. The aggregated V205 were partially re-dispersed during the regeneration process, and the intrinsic oxidation of ammonia with high concentrations of O2 is a factorthat suppresses the catalytic activity.展开更多
By using Moire′ pattern formed by the double diffraction of precipitated V_4C_3 and matrix of γ-phase,the nature of the structure of the interface between precipitated V_4C_3 and matrix as well as the retarding effe...By using Moire′ pattern formed by the double diffraction of precipitated V_4C_3 and matrix of γ-phase,the nature of the structure of the interface between precipitated V_4C_3 and matrix as well as the retarding effect of V4C3 particles on the development of deformation twins have been investigated.It is shown that partially coherent interfaces exist between V_4C_3 and ma- trix.Twinning dislocations may transform into interfacial dislocations under external stress, and may move continuously through bypassing or cross-sliping.展开更多
The inheritance phenomenon of precipitated V_4C_3 in martensitic transformation has been in- vestigated by means of electron diffraction and matrix analysis.A crystallographic orientation relation among austenite,mart...The inheritance phenomenon of precipitated V_4C_3 in martensitic transformation has been in- vestigated by means of electron diffraction and matrix analysis.A crystallographic orientation relation among austenite,martensite and V_4C_3 carbide was found to be. (010)_A∥( 10)_M∥(010)_(v_4c_3), [10 ]∥[11 ]_M [10 ]_(v_4c_3) The V_4C_3 first precipitated in austenite,and then was inherited to martensite.Although cer- tain orientation relation was kept between V_4C_3 and martensite,the interfacial structural ana- lysis pointed out that the biphase interfacial energy is higher than that determined by Baker-Nutting relation,thus it is metastable.Because the V_4C_3 precipitated along the crystalline defects in austenite,they could be inherited to martensite.展开更多
用乙炔碳作为碳源,采用机械活化辅助碳热还原两步法合成xLi_3V_2(PO_4)_3·LiVPO_4F/C复合正极材料。采用XRD、SEM、TEM等技术对样品的晶体结构和微观形貌进行了表征,采用循环伏安法和恒流充放电等测试方法对合成样品的电化学性能...用乙炔碳作为碳源,采用机械活化辅助碳热还原两步法合成xLi_3V_2(PO_4)_3·LiVPO_4F/C复合正极材料。采用XRD、SEM、TEM等技术对样品的晶体结构和微观形貌进行了表征,采用循环伏安法和恒流充放电等测试方法对合成样品的电化学性能进行分析研究。结果表明:xLi_3V_2(PO_4)_3·LiVPO_4F/C复合正极材料兼备了Li_3V_2(PO_4)_3的循环稳定性好、倍率性能佳的优点和LiVPO_4F能量密度高的优势,此外还弥补了Li_3V_2(PO_4)_3在3～4.7 V电压范围充放电时放电电压平台缺失的缺陷。该材料在3～4.7 V之间的循环稳定性较好,在1C倍率下最高放电比容量为119.7 m A·h/g,循环300圈后为97.5 m A·h/g。其倍率性能较好,在0.1C倍率下充放电可获得高达152 m A·h/g的放电比容量,倍率升高到8C时仍能保持100 mA·h/g的放电比容量。展开更多
文摘An effective method for the regeneration of thermally deactivated commercial monolith SCR catalysts was investigated. Two types of regenerated solutions, namely NH4C1 （l mol/L） and dilute H2SO4 （0.5 tool/L）, were employed to treat the used catalyst. The effects of temperature and the regeneration process on the structural and textural properties of the catalysts were determined by X-ray diffraction, scanning electron microscopy, N2 adsorption/desorption, elemental analysis and Fourier transform infrared spectroscopy. The results suggest that the anatase phase of the used catalyst is maintained after exposure to high temperatures. Some of the catalytic activity was restored after regeneration. The catalyst regenerated by aqueous NH4C1 had a higher activity than that of the catalyst treated by dilute H2SO4. The main reason is that the NH3 generated from the decomposition of NH4C1 at high temperatures can be adsorbed onto the catalyst which promotes the reaction. The aggregated V205 were partially re-dispersed during the regeneration process, and the intrinsic oxidation of ammonia with high concentrations of O2 is a factorthat suppresses the catalytic activity.
文摘By using Moire′ pattern formed by the double diffraction of precipitated V_4C_3 and matrix of γ-phase,the nature of the structure of the interface between precipitated V_4C_3 and matrix as well as the retarding effect of V4C3 particles on the development of deformation twins have been investigated.It is shown that partially coherent interfaces exist between V_4C_3 and ma- trix.Twinning dislocations may transform into interfacial dislocations under external stress, and may move continuously through bypassing or cross-sliping.
文摘The inheritance phenomenon of precipitated V_4C_3 in martensitic transformation has been in- vestigated by means of electron diffraction and matrix analysis.A crystallographic orientation relation among austenite,martensite and V_4C_3 carbide was found to be. (010)_A∥( 10)_M∥(010)_(v_4c_3), [10 ]∥[11 ]_M [10 ]_(v_4c_3) The V_4C_3 first precipitated in austenite,and then was inherited to martensite.Although cer- tain orientation relation was kept between V_4C_3 and martensite,the interfacial structural ana- lysis pointed out that the biphase interfacial energy is higher than that determined by Baker-Nutting relation,thus it is metastable.Because the V_4C_3 precipitated along the crystalline defects in austenite,they could be inherited to martensite.
文摘用乙炔碳作为碳源,采用机械活化辅助碳热还原两步法合成xLi_3V_2(PO_4)_3·LiVPO_4F/C复合正极材料。采用XRD、SEM、TEM等技术对样品的晶体结构和微观形貌进行了表征,采用循环伏安法和恒流充放电等测试方法对合成样品的电化学性能进行分析研究。结果表明:xLi_3V_2(PO_4)_3·LiVPO_4F/C复合正极材料兼备了Li_3V_2(PO_4)_3的循环稳定性好、倍率性能佳的优点和LiVPO_4F能量密度高的优势,此外还弥补了Li_3V_2(PO_4)_3在3～4.7 V电压范围充放电时放电电压平台缺失的缺陷。该材料在3～4.7 V之间的循环稳定性较好,在1C倍率下最高放电比容量为119.7 m A·h/g,循环300圈后为97.5 m A·h/g。其倍率性能较好,在0.1C倍率下充放电可获得高达152 m A·h/g的放电比容量,倍率升高到8C时仍能保持100 mA·h/g的放电比容量。
