沉淀剂对CH_4-CO_2重整Ni/MgO催化剂结构和性能的影响

Study on Ni/MgO Catalysts for CH_4-CO_2 Reforming——Influences of precipitators on Physico-chemical Properties and Catalytic Performance of Catalysts

分别采用氢氧化钾和碳酸钾溶液为沉淀剂,制备了两种Ni/MgO催化剂(依次标记为NM1、NM2),用BET、XRD、TPR、TG及活性评价等方法考察了沉淀剂对Ni/MgO催化剂的物化性质和催化性能的影响。研究结果表明,两种催化剂中的镍物种虽均以镍镁固溶体形式存在,但还原性能存在明显差异,NM1中镍物种与载体具有较强的相互作用。与NM2相比,NM1具有较大的比表面和较小的镍镁固溶体晶粒度,还原后的NM1催化剂中镍晶粒也相对较小。在CH4 CO2重整反应中,NM1呈现了较高的催化活性和选择性。

Using KOH and K_2CO_3 as precipitators, two NiO/MgO catalysts, labeled as NM1 and NM2, were prepared respectively, and the effects of precipitators on the physicochemical properties and catalytic performance of the two NiO/MgO catalysts were studied by means of BET, XRD, TPR, TG and catalytic reaction activity evaluation. It was found that the nickel in both catalysts were present in form of nickel-magnesian solid solution, but there existed obvious different reductive property between the two catalysts. Compared with NM2, NM1 had higher specific surface area and smaller crystallites size of nickel-magnesian solid solution, and after reduction NM1 also had smaller size of nickel crystallites. Therefore, NM1 showed better catalytic performances for methane reforming with carbon dioxide than NM2.