费-托合成Co/ZrO2-Al2O3催化剂反应性能的研究

以ZrOCl2·6H2O和AlCl3为原料，采用共沉淀方法制得一系列不同ZrO2质量分数的ZrO2-Al2O3混合氧化物载体；并以该混合氧化物为载体，采用初湿浸渍法制得钴质量分数为12％的Co/ZrO2-Al2O3催化剂。XRD、NH3-TPD、TPR和原位IR等表征结果表明，随着混合载体中ZrO2质量分数的增加，载体比表面积先增加后减少，混合载体的平均孔径则小于单一氧化物ZrO2和Al2O3的平均孔径。ZrO2和Al2O3载体混合后会导致氧化物的比表面积和酸性增大并且有新的物相生成。当混合氧化物用作载体时，能够抑制载体表面金属钴的分散，改变催化剂的还原行为，降低催化剂对CO物种的吸附能力。CO加氢反应表明，与单一金属氧化物相比，钴负载ZrO2-Al2O3混合氧化物催化剂的加氢活性和重质烃选择性有所降低。

Study on reaction performance of Co/ZrO2-Al2O3 catalysts for Fischer-Tropsch synthesis

A series of ZrO2-Al2O3 mixed oxides with different ZrO2 contents were prepared using ZrOCl2·6H2O and AlCl3 as the raw material by means of co-precipitation method. The Co/ZrO2-Al2O3 catalysts with 12% cobalt loading were prepared using the incipient wetness impregnation method. XRD, NH3-TPD, TPR and in situ IR characterization results show that surface areas of the mixed oxides support are first increased and then decrease with the increase of the ZrO2 content in the mixed oxides. The average pore size of the mixed oxides is smaller than that of the single ZrO2 or Al2O3 oxides. When the mixed oxides were used as the support of the cobalt-based catalyst, the mixture of zirconia and alumina can result in the increase of the surface area and support acidity. Meanwhile, a new crystal phase could also be formed due to the interaction between alumina and zirconia. When the ZrO2-Al2O3 mixed oxides were used as the supports of the cobalt-based catalysts, the dispersion of metallic cobalt and the amount of adsorbed CO species on the surface of the catalysts are reduced and the reduction behaviors of cobalt oxides are changed. In the test of the F-T reaction, CO hydrogenation demonstrated that cobalt supported on ZrO2-Al2O3 mixed oxides have lower catalytic activity and C5+ selectivity compared with the cobalt supported on the single alumina or zirconia catalysts.