沉淀法ZrO2载体的制备、表征及其甲烷化催化性能初探

Preparation of ZrO2 carrier by precipitation,characterization and catalytic performance for methanation

以氧氯化锆溶液为前驱体、氨水为沉淀剂,通过沉淀法合成新型多孔ZrO2载体。利用正交实验考察了氧氯化锆浓度、分散剂质量、反应时间、焙烧时间等因素对ZrO2载体比表面积的影响,并得到合成多孔ZrO2载体的最佳工艺条件:氧氯化锆溶液浓度为0.6 mol/L、分散剂PEG-6000的质量为3 g、反应时间为30 min、焙烧时间为2 h。对该条件下合成的ZrO2载体进行BET、SEM、XRD和粒度表征,结果表明,合成的ZrO2载体粒度小、晶型完美、表面疏松、比表面积大,适合做负载型催化剂的新型载体材料。通过浸渍法载镍制得Ni/ZrO2催化剂,初步检测了其甲烷化催化活性,在470℃高温条件下,CO转化率高达90%,CH4选择性达98%,表现出较高的活性。

A novel porous ZrO2 carrier is synthesized through precipitation method by using a zirconium oxychloride solution as a precursor and ammonia as a precipitant.The effects of zirconium oxychloride concentration,dispersant dosage,reaction time and roasting time on the specific surface area of ZrO2 carrier are investigated through orthogonal experiment.Via orthogonal analysis,the optimal process conditions for the synthesis of porous ZrO2 carrier are obtained as follows:the concentration of zirconium oxychloride solution is 0.6 mol·L-1,the dosage of polyethylene glycol-6000 dispersant is 3 g,the reaction lasts for 30 min,and the roasting time is 4 hours.ZrO2 carrier synthesized under the optimum conditions is characterized by BET,SEM,XRD and particle size.The results show that the synthesized ZrO2 carrier exhibits small particle size,perfect crystal form,loose surface and large specific surface area,which is suitable for a carrier to catalysts.Ni/ZrO2 catalyst is prepared by impregnation method,and its catalytic activity in methanation is preliminarily detected.It is found that the CO conversion rate reaches as high as 90%and the selectivity of CH4 can reach 98%at 470℃,representing a high activity.