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用稳定态活性测试法研究了一系列不同载钠量Ni/Al_2O_3催化剂上的CO_2加氢甲烷化行为,并对它们进行了XRD和程序升温还原表征。实验结果表明,在所用钠量范围内,于Ni/Al_2O_3上的CO_2加氢生成甲烷的活性随Na加入量的改变而变化,这与催化剂上Ni物种的分配有关,673K附近还原出的Ni物种可能是良好的CO_2加氢甲烷化活性中心。Na助剂的作用主要是改变Ni物种的分配。通过Na助剂的加入,可获得在化学剂量CO_2/H_2比下使CO_2几乎完全转化为甲烷的低镍催化剂。
The steady-state activity test was used to study the CO_2 hydromethanation behavior of a series of Ni / Al 2 O 3 catalysts with different loadings of sodium. The catalysts were characterized by XRD and temperature programmed reduction. The experimental results show that the activity of hydrogenation of CO_2 on Ni / Al_2O_3 over Ni / Al_2O_3 in the range of sodium used varies with the addition of Na, which is related to the distribution of Ni species on the catalyst. The Ni species reduced near 673K It may be a good CO 2 hydromethanation activity center. The role of Na auxiliaries is mainly to change the distribution of Ni species. Through the addition of Na promoter, a low-nickel catalyst that can almost completely convert CO 2 to methane at a chemical CO 2 / H 2 ratio can be obtained.