焙烧温度对Ni/CaO-Al2O3结构及其催化重整性能的影响

采用共沉淀法制备了一系列具有类水滑石结构前驱体的Ni/CaO-Al₂O₃复合催化剂，考察了制备过程中焙烧温度对复合催化剂结构及性能的影响。结果表明，焙烧温度可调控活性组分Ni与载体之间的相互作用力，进而调变复合催化剂的比表面积、活性组分Ni的颗粒粒径。当焙烧温度为700 ℃时，Ni与载体之间相互作用力适宜，复合催化剂具有最大的比表面积（21.42 m²/g）和最小的Ni颗粒粒径（19.51 nm）；该复合催化剂在CO₂吸附强化CH₄/H₂O重整制氢过程中可得到98.31%的H₂浓度和94.87%的CH₄转化率，循环10次后，H₂浓度仍能保持在97.35%以上。这是因为大的比表面积为反应提供了更多的活性位点，利于CO₂吸附过程的强化，而小的Ni颗粒粒径提高了复合催化剂的抗烧结能力。

Influence of calcination temperature on the structure and catalytic reforming performance of Ni/CaO-Al2O3 catalyst

Considering the tunable structure of hydrotalcite-like compounds, co-precipitation method was employed to synthesize Ni/CaO-Al₂O₃ composite catalysts. The influence of calcination temperature on the structure and catalytic reforming performance of Ni/CaO-Al₂O₃ catalyst investigated. The results showed that the specific surface area and Ni particle size of the as-synthesized composite catalysts were greatly affected by the calcination temperature of the precursor, which derived from the variable interaction between the Ni and the support. When the calcination temperature was 700°C, the composite catalyst obtained a specific surface area of 21.42 m²/g and Ni particle size of 19.51 nm. The catalytic evaluation showed that the composite catalyst possessed a H₂ concentration of 98.31% and a CH₄ conversion of 94.87%, and H₂ concentration exceeded 97.35% even after 10 cyclic runs. The high catalytic activity was ascribed to the higher specific surface area, which provided more active sites and enhanced CO₂ sorption. The smaller Ni particle size improved the anti-sintering capacity of the composite catalyst, endowing the composite catalyst superior stability.