以类水滑石为前驱体制备Ru基CH_4-CO_2重整催化剂

Preparation of Ru catalysts from hydrotalcite-like compounds for carbon dioxide reforming of methane

以类水滑石为前驱体,采用共沉淀法制备了不同Ru含量的xRu/Mg(Al)O催化剂(x=1,2,4),采用XRD、H2-TPR和CO脉冲吸附等表征催化剂结构和Ru金属分散度,并评价Ru含量对CH4-CO2重整反应活性与稳定性的影响。XRD与CO脉冲吸附结果表明,Ru含量增加时,还原后Ru金属颗粒的表面活性位数目增加,但分散度降低,Ru金属的粒径增大。活性测试结果表明,Ru质量分数为2%时,催化剂活性最高。Ru质量分数为1%时,催化剂具有较好的稳定性,归属于高分散Ru金属颗粒与Mg(Al)O载体之间的强相互作用。

Using hydrotalcite-like compounds as the precursor, a series of supported Ru/Mg（A1） O cata- lysts with Ru mass fractions of 1% ,2% and 4% were prepared by coprecipitation method. The catalysts were characterized by using the techniques of XRD, H2-TPR and CO chemisorptions. The influence of Ru loadings on the activity and stability of the catalysts for CH4-CO2 reforming reaction was investigated. The results of XRD and CO chemisorption indicated that the number of Ru surface active sites on Ru metal particles increased with the increase of Ru loadings, however, higher Ru loading led to lower metal disper- sion and larger metal particles. The results of activity tests showed that the highest activity was achieved on 2Ru/Mg（A1） O catalyst, and 1 Ru/Mg（A1） O catalyst exhibited higher stability at 750 ℃ for reaction time 30 h, which might be related to the strong interaction between the highly dispersed Ru metal particles and Mg （A1） O support.