Influence of preparation method on the properties and catalytic performance of Ni/La2O3/Al2O3 catalyst for dry reforming of methane
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摘要: 采用浸渍法及蒸发法制备了Ni/La2O3/Al2O3催化剂,考察了制备方法对其结构及甲烷干重整催化性能的影响。通过XRD、H2TPR、BET、TEM、TG-DSC等方法对催化剂进行了表征。结果表明,浸渍法制备的催化剂具有较好的Ni分散性、更均匀的粒径分布,较大的比表面积及更优的孔结构,从而具有更好的Ni抗烧结能力及抗积炭性。浸渍法制备的催化剂平均积炭速率很低,约为0.6737mg/(gcat·h),相当于蒸发法制备催化剂的21%。活性测试结果表明,浸渍法制备的催化剂上CH4、CO2转化率及H2、CO选择性比蒸发法制备的催化剂分别高约5%、10%及4%、3%,具有更好的稳定性。Abstract: Ni/La2O3/Al2O3 catalysts were prepared by the methods of incipient wetness impregnation and evaporation. The influence of preparation method on the physicochemical properties and catalytic performance for the dry reforming of methane was investigated. The catalysts were characterized by X-ray diffraction (XRD), temperatureprogrammed reduction (H2-TPR), BET surface area, transmission electron microscopy (TEM), and thermogravimetry and differential scanning calorimetry (TG-DSC). The catalyst prepared by incipient wetness impregnation exhibited better Ni dispersion, more symmetrical distribution of particle diameter, larger specific surface area and more rational pore structure than that prepared by evaporation. As a result, the catalyst prepared by the incipient wetness impregnation possessed better resistance to Ni sintering and coking; its average coking rate was about 0.6737 mg/(gcat·h), only equivalent to 21% of the value of the catalyst prepared by evaporation. Moreover, the catalysts prepared by wetness impregnation exhibited much higher conversions of CH4 and CO2, higher selectivities of H2 and CO, as well as better stability for methane dry reforming than the catalyst prepared by evaporation.
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Key words:
- preparation method /
- dry reforming of methane /
- lanthanum oxide /
- nickel /
- alumina /
- catalyst structure
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