Ni/Al_2O_3催化剂的CO_2-TPD表征

Ni/Al_2O_3催化剂是甲烷二氧化碳重整反应制取合成气研究最多、最具应用潜力的一种催化剂。通过对催化剂进行CO_2-TPD研究,考察还原态Ni/Al_2O_3催化剂的CO_2脱附特性。结果表明,浸渍法制备的Ni/Al_2O_3催化剂CO_2脱附曲线呈现双峰,分别在(60~65)℃和(350~380)℃出现高低温两个活性位;高温CO_2吸附量为3.0 cm~3·g~(-1),低温CO_2吸附量为24.0 cm~3·g~(-1)。催化剂的CO_2吸附量与其Ni含量无关。考察选用不同载体的CO_2脱附行为,发现以Al_2O_3为载体的催化剂CO_2吸附量是MgO和SiO_2为载体催化剂的2~4倍,以TiO_2为载体的催化剂几乎不吸附CO_2。

CO2-TPD characterization of Ni/Al2O3 catalyst

Ni/Al₂O₃ catalyst is one of the most used and the most promising catalysts for the synthesis of syngas from methane and carbon dioxide reforming.The performance of the reduced Ni/Al₂O₃ catalysts for CO₂ desorption was investigated by CO₂-TPD characterization.The results showed that CO₂ desorption curve over Ni/Al₂O₃ catalyst prepared by impregnation method was bimodal,and two active sites of high and low temperature appeared in (60-65) ℃ and (350-380) ℃,respectively.At the temperature of (60-65) ℃,CO₂ adsorption amount was 24.0 cm³·g^-1, at the temperature of (350-380) ℃, the amount of CO₂ adsorption was 3.0 cm³·g^-1.The adsorption amount of CO₂ over the catalyst was independent of Ni content of the catalyst.CO₂ desorption behaviors of the catalysts with different carriers were investigated.It was found that CO₂ adsorption amount over the catalyst using Al₂O₃ as the support was 2-4 times of that over the catalysts using MgO and SiO₂ as the supports.The catalysts with TiO₂ as the support hardly adsorbed CO₂.