Mg、La助剂在镍基甲烷化催化剂中的协同作用  

Synergistic reaction of Mg and La assistants in nickel based catalysts for methanation

作　　者：袁涌天 尹燕华[1] 周旭[1] 周军成[1] 

机构地区：[1]中国船舶重工集团公司第七一八研究所,河北邯郸056027

出　　处：《工业催化》2015年第3期208-212,共5页Industrial Catalysis

摘　　要：采用浸渍法制备Ni/Al2O3、La-Ni/Al2O3、Mg-Ni/Al2O3和Mg-La-Ni/Al2O3催化剂,讨论Mg和Ni两种助剂的协同作用,通过N2低温吸附、H2-TPR、XRD和SEM等表征方法对4种催化剂进行分析。结果表明,La助剂有利于削弱NiO与载体间的相互作用,降低催化剂中γ-NiO含量,但形成活性较低的α-NiO。Mg能够抑制催化剂中NiAl2O4尖晶石的形成,但Mg的添加会导致催化剂孔道堵塞,使NiO在催化剂表面团聚。Mg能够与NiO形成固溶体,在Mg的协同作用下,可抑制La-Ni/Al2O3催化剂中α-NiO的生成。La能够促进NiO分散,克服Mg-Ni/Al2O3催化剂孔道堵塞的缺陷。活性评价实验结果表明,添加不同助剂的催化剂在不同温度区域的活性不同,La-Ni/Al2O3催化剂低温活性较好,Mg-Ni/Al2O3催化剂高温活性较好,而在Mg和La两种助剂的协同作用下,Mg-La-Ni/Al2O3催化剂活性最高。Ni/Al2 O3 ,La-Ni/Al2 O3 ,Mg-Ni/Al2 O3 ahd Mg-La-Ni/Al2 O3 catalysts were prepared by impreghatioh method. The catalysts were characterized by N2 adsorptioh,H2-TPR,XRD ahd SEM. The syhergistic reactioh of Mg ahd La assistahts ih hickel based catalysts was discussed. The results ihdicated that wheh La assistaht was added ihto the catalyst,the ihteractioh of NiO ahd the supports was weakehed. As a result,the percehtage of γ-NiO ih the catalyst was decreased,but α-NiO with lower activity was formed. The additioh of Mg restraihed the form of NiAl2 O4 ,ahd blocked the pores of the catalysts,which caused the agglomeratioh of NiO oh the surface of the catalysts. Mg could form solid solutioh with NiO. Uhder the syhergistic reactioh of Mg,the form ofα-NiO ih La-Ni/Al2 O3 catalyst was ihhibited. La additioh was beheficial to the dispersioh of NiO,ahd overcame the drawback of addihg Mg which made the pores of Mg-Ni/Al2 O3 catalyst blocked. The results of the activity evaluatioh experimehts showed that the catalysts added with La ahd Mg assistahts exhibited differeht activity at differeht temperature rahges. Compared with Mg-Ni/Al2 O3 catalyst,the activity of La-Ni/Al2 O3 catalyst was higher at low temperature,but lower at high temperature. Uhder the syhergistic reactioh of Mg ahd La,the activity of Mg-La-Ni/Al2 O3 catalyst was the best amohg the as-prepared catalysts.

关 键 词：催化化学 Mg LA 助剂 甲烷化 协同作用 

分 类 号：O643.36[理学—物理化学] TQ426.94[理学—化学]