碱土金属对甲烷与空气制合成气Ni/CaO-Al_2O_3催化剂性能的影响

EFFECT OF BASE-EARTH METAL PROMOTER ON BEHAVIORS OF Ni/CaO-Al_2O_3 CATALYST FOR OXIDATION OF METHANE WITH AIR

考察了添加在镍基催化剂中的碱土金属助剂对甲烷与空气制合成气的催化反应性能的影响。并对催化剂用TPO、TPR、CO2 TPD、XPS及CO脉冲色谱对催化剂进行了表征。实验表明 ,碱土金属助剂对降低催化剂结炭有一定的作用 ,催化剂抗积炭顺序为Ni BaO CaO Al2 O3>Ni SrO CaO Al2 O3>Ni MgO CaO Al2 O3>Ni CaO Al2 O3。而且 ,添加了碱土金属催化剂的Ni晶粒减小、结合能负位移和催化剂吸附CO2 的能力变化顺序都与积炭量减少顺序一致。其中尤以Ni BaO CaO Al2 O3 催化剂既有较高的活性 。

This article mainly concerns the influence of base earth metal promoter in Ni base catalyst for catalytic oxidation of methane with air to syngas These catalysts promoted by base earth metals were investigated by using TPR, TPO, CO 2 TPD, XPS and CO pulse chromatograph It was found that the base earth metal promoter is effective in the suppression of carbon deposition on catalyst The abilities of resistance to carbon deposition are ordered as below: Ni BaO/CaO Al 2O 3>Ni SrO/CaO Al 2O 3>Ni MgO/CaO Al 2O 3>Ni/CaO Al 2O 3 Especially, the catalyst Ni BaO/CaO Al 2O 3 has not only higher activity and selectivity, but also better resistance to carbon deposition Meanwhile, it is found that, the activities of the catalysts promoted by base earth metals all decreased somewhat below 800?℃ except for the Ni BaO/CaO Al 2O 3 It was also found that the addition of base earth metals resulted in decreasing of the size of nickel grain, the negative displace of the electron binding energies and the increasing of the amount of CO 2 adsorption Moreover, the orders of these changes are all in accordance with the results of carbon deposition It is assumed that these changes contributed to the improvement of the ability of resistance to carbon deposition on the catalyst