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采用共浸渍法制备了不同Ni含量的Cu/γ-Al2O3催化剂,在固定床反应器上考察了该催化剂在含硫(SO2,0.01%,体积分数)气氛中对低浓度甲烷(3%)的催化燃烧活性及抗硫中毒稳定性。结果表明,SO2会使Cu/γ-Al2O3催化剂发生硫中毒,Ni的加入可增强其抗硫性能,而且随着Ni含量的增加,其抗硫性改善效果越明显。在Ni含量为10%的Cu/γ-Al2O3催化剂上反应10 h后,甲烷转化率仍可保持在96%以上。SEM、XRD和TPD表征结果显示,Ni的加入促使Cu/γ-Al2O3催化剂表面生成NiAl2O4尖晶石相,提高了催化剂的稳定性。随着Ni含量的增加,催化剂表面Lewis酸性降低,吸附SO2的能力减弱,可延缓催化剂硫中毒,同时也缩短了CO2分子在催化剂表面的停留时间,从而提高了甲烷催化燃烧效率。
The Cu / γ-Al2O3 catalysts with different Ni contents were prepared by co-impregnation method. The catalysts were characterized on low-concentration methane (3%) in the presence of sulfur (SO2, 0.01% Catalytic combustion activity and anti-sulfur poisoning stability. The results show that SO2 can cause sulfur poisoning on Cu / γ-Al2O3 catalyst. Adding Ni can enhance its sulfur resistance, and its anti-sulfur effect is more obvious with the increase of Ni content. Methane conversion can still be maintained above 96% after 10 h reaction on Cu / γ-Al2O3 catalyst with Ni content of 10%. The results of SEM, XRD and TPD showed that Ni addition promoted the formation of NiAl2O4 spinel on the surface of Cu / γ-Al2O3 catalyst and improved the stability of the catalyst. With the increase of Ni content, the Lewis acidity of catalyst surface decreased and the ability of adsorbing SO2 decreased, which could delay the sulfur poisoning of catalyst and shorten the residence time of CO2 molecules on the catalyst surface, thus increasing the methane catalytic combustion efficiency.