氧化铝负载Co-Mo双金属氧化物的共沉淀制备

采用双溶剂体系(硝酸铝和硝酸钴的乙醇溶液与钼酸铵的碳酸铵水溶液)共沉淀制备了氧化铝负载Co-Mo双金属氧化物。研究了双溶剂体系中乙醇和水的体积比对共沉淀的影响,考察了老化时间对氧化物结构参数的影响,研究了焙烧温度对氧化物还原性能的影响。结果表明:乙醇和水体积比对钼酸根离子的沉淀有重要影响,为了保证钼酸根离子的完全沉淀,乙醇的体积要随着MoO3负载量的增加而提高;随着老化时间的增加,氧化物的比表面积先增加后下降,6 h老化的样品具有最大的比表面积;低温焙烧制得的氧化物较容易还原。

Preparation of Cobalt-Molybdenum bimetallic oxides supported on alumina by Co-precipitation method

Cobalt-molybdenum bimetallic oxides supported on alumina were prepared by co-precipitation method with ethanol-water binary solvent system,which is composed of ethanol solution of aluminium nitrate and cobalt nitrate,and aqueous solution of ammonium carbonate and ammonium molybdate.The effects of ethanol/water volume ratio and MoO3 loading on the coprecipitation were invesitigated.X-ray diffraction(XRD),N2 physical adsorption and temperature programmed reduction(TPR) were employed to characterize the oxides.Results show that the precipitation of Mo7O6-24 ions was affected by the ethanol/water volume ratio and MoO3 loading.The volume of ethanol to guarantee the precipitation of Mo7O6-24 ions should be increased with the increase of MoO3 loading.The specific surface area firstly increased then decreased with the increase of aging time.The oxide with aging time of 6 h has the largest specific surface area.The oxides calcined at low temperature are reduced more easily than that calcined at high temperature.