A series of sulfided tertiary NiMoP/ γ Al 2O 3 catalysts with different contents of MoO 3 were prepared by using molybdophosphoric acid of Keggin structure(H 3PMo 12 O 40 ) and nickel nitrate as origins of active pha...A series of sulfided tertiary NiMoP/ γ Al 2O 3 catalysts with different contents of MoO 3 were prepared by using molybdophosphoric acid of Keggin structure(H 3PMo 12 O 40 ) and nickel nitrate as origins of active phase components of molybdenum, phosphorus and nickel, and characterized by TPR technique, with their HDS activity being investigated with thiophene as a model substrate. For the sulfided Mo 0 catalyst containing no nickel as promoter, the only hydrogen sulfide evolution peak Ⅰ is observed at 462 K and attributed to the hydrogenation of the so called edge sulfur atoms chemisorbed on coordinatively unsaturated(cus) Mo x+ sites on the MoS 2 phase(MoS 2 slab). With the introduction of nickel into the active phase of the sulfided Mo 0 catalyst and with the increase of the molybdenum loading, a new hydrogen sulfide evolution peak Ⅱ gradually develops at the low temperature side of the peak Ⅰ, at the same time accompanied by both the increase of the area ratio of the peak Ⅱ to the peak Ⅰ and the shift of the hydrogen sulfide evolution maximum rate to lower temperatures, which may imply the existence of two kinds of active centers related to molybdenum and nickel respectively and the synergic action between the two centers above. It should be noted that for the sulfided NiMoP/ γ Al 2O 3 catalysts, the thiophene HDS rate and the quantity of hydrogen sulfide evolved during TPR process increase monotonously with the atomic ratio of molybdenum to nickel in the form of [ n (Ni)+ n (Mo)]/ n (Ni). On the basis of the results here, the conclusion may be reached that the two kinds of vacancies can be formed on the edge of Ni Mo S slab due to the loss of S during TPR process and vacancies or sites related to the H 2S evolution peak II should be regarded as the mainly active reaction centers of thiophene HDS.展开更多
针对复杂决策环境下的决策者倾向于使用定性评价数据和现实环境中数据信息通常存在正态分布规律的问题,构建了基于犹豫正态语言有序加权平均(hesitant normal linguistic ordered weighted average,HNLOWA)算子的决策模型。将正态模糊...针对复杂决策环境下的决策者倾向于使用定性评价数据和现实环境中数据信息通常存在正态分布规律的问题,构建了基于犹豫正态语言有序加权平均(hesitant normal linguistic ordered weighted average,HNLOWA)算子的决策模型。将正态模糊数和犹豫模糊语言元相结合,引入了犹豫正态语言元(hesitant normal linguistic element,HNLE)的概念,其不仅能够运用语言变量来描述决策信息,还能传递出语言决策信息的分布情况;定义了HNLE之间的基本运算法则和大小判别准则,并设计HNLOWA算子用于对HNLE进行信息融合,同时探究了HNLOWA算子的相关性质;构建了基于HNLOWA集成算子的多属性决策方法,并运用推荐系统选择评估案例进行了模型的验证分析。展开更多
文摘A series of sulfided tertiary NiMoP/ γ Al 2O 3 catalysts with different contents of MoO 3 were prepared by using molybdophosphoric acid of Keggin structure(H 3PMo 12 O 40 ) and nickel nitrate as origins of active phase components of molybdenum, phosphorus and nickel, and characterized by TPR technique, with their HDS activity being investigated with thiophene as a model substrate. For the sulfided Mo 0 catalyst containing no nickel as promoter, the only hydrogen sulfide evolution peak Ⅰ is observed at 462 K and attributed to the hydrogenation of the so called edge sulfur atoms chemisorbed on coordinatively unsaturated(cus) Mo x+ sites on the MoS 2 phase(MoS 2 slab). With the introduction of nickel into the active phase of the sulfided Mo 0 catalyst and with the increase of the molybdenum loading, a new hydrogen sulfide evolution peak Ⅱ gradually develops at the low temperature side of the peak Ⅰ, at the same time accompanied by both the increase of the area ratio of the peak Ⅱ to the peak Ⅰ and the shift of the hydrogen sulfide evolution maximum rate to lower temperatures, which may imply the existence of two kinds of active centers related to molybdenum and nickel respectively and the synergic action between the two centers above. It should be noted that for the sulfided NiMoP/ γ Al 2O 3 catalysts, the thiophene HDS rate and the quantity of hydrogen sulfide evolved during TPR process increase monotonously with the atomic ratio of molybdenum to nickel in the form of [ n (Ni)+ n (Mo)]/ n (Ni). On the basis of the results here, the conclusion may be reached that the two kinds of vacancies can be formed on the edge of Ni Mo S slab due to the loss of S during TPR process and vacancies or sites related to the H 2S evolution peak II should be regarded as the mainly active reaction centers of thiophene HDS.
文摘针对复杂决策环境下的决策者倾向于使用定性评价数据和现实环境中数据信息通常存在正态分布规律的问题,构建了基于犹豫正态语言有序加权平均(hesitant normal linguistic ordered weighted average,HNLOWA)算子的决策模型。将正态模糊数和犹豫模糊语言元相结合,引入了犹豫正态语言元(hesitant normal linguistic element,HNLE)的概念,其不仅能够运用语言变量来描述决策信息,还能传递出语言决策信息的分布情况;定义了HNLE之间的基本运算法则和大小判别准则,并设计HNLOWA算子用于对HNLE进行信息融合,同时探究了HNLOWA算子的相关性质;构建了基于HNLOWA集成算子的多属性决策方法,并运用推荐系统选择评估案例进行了模型的验证分析。
