氧化铈和铈锆固溶体对Pd催化剂抗硫性能影响的研究

采用等体积浸渍法制备了质量分数为1%Pd/γ－Al₂O₃、1%Pd/10%CeO₂/γ-Al₂O₃以及1% Pd/10%Ce_0.6Zr_0.4O₂ /γ－Al₂O₃催化剂，研究了CeO₂和Ce_0.6Zr_0.4O₂ 固溶体对Pd催化剂抗硫性能的影响。利用XRD和XPS技术表征了催化剂的固相结构、表面元素组成和反应后催化剂中硫物种（或表面硫酸盐）的存在形态。利用SO₂-TPD研究了SO₂在催化剂上的吸附和脱附行为。实验结果表明，在催化剂载体中引入CeO₂和Ce_0.6Zr_0.4O₂ 降低了催化剂起燃活性；SO₂ 在Pd/Ce_0.6Zr_0.4O₂ /γ－Al₂O₃催化剂表面上发生化学反应生成Zr(SO₄)₂，其热稳定性大于在Pd/γ－Al₂O₃和Pd/CeO₂/γ－Al₂O₃催化剂表面上的硫酸盐或硫酸盐物种。

Effect of CeO2 and Ce0.6Zr0.4O2 solid solution on the sulfur tolerance of Pd-based catalysts

1%Pd/γ-Al₂O₃,1%Pd/10%CeO₂/γ-Al₂O₃ and 1%Pd/10%Ce_0.6Zr_0.4O₂/γ-Al₂O₃ catalysts were prepared by incipient wetness impregnation method. Effects of CeO₂ and Ce_0.6Zr_0.4O₂ solid solution on tolerance to sulfur of Pd-based catalyst were investigated. The solid structure, surface elemental composition and state of sulfur species(or surface sulfates) in the catalysts after reaction were characterized using X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). adsorption/desorption of SO₂ on the catalysts were studied using SO₂ temperature-programmed desorption (SO₂-TPD). The results showed that doping of CeO₂ and Ce_0.6Zr_0.4O₂lowered the combustion-initiating temperature; Zr(SO₄)₂ formed on 1%Pd/10%Ce_0.6Zr_0.4O₂γ-Al₂O₃ catalyst, whose thermal stability was higher than sulfates formed on 1%Pd/10%CeO2/γ-Al₂O₃ and 1% Pd/10 % Ce_0.6Zr_0.4O₂/γ-Al₂O₃.