Al的加入对CeZr固溶体催化剂结构及其乙苯脱氢活性的影响

摘要

For improving the oxygen storage/release capacity of ceria-zirconia solid solution, Ce0. 5 Zr0. 5 O2-Al2 O3 mixed oxides were prepared by a co-precipitation method and applied in the oxidative dehydrogenation of ethylbenzene to styrene with carbon dioxide. Ce0. 5 Zr0. 5 O2-Al2 O3 mixed oxides were characterized by powder X-ray diffraction, Raman spectroscopy, N2-sorption, H2 temperature-programmed reduction, and X-ray photoelectron spectroscopy. Results show that Al2 O3 acts as a diffusion barrier. The addition of Al prevents the growth of Ce0. 5 Zr0. 5 O2 crystallite size, increases the specific surface area and oxygen storage capacity of Ce0. 5 Zr0. 5 O2-Al2 O3 mixed oxides. The specific surface area and oxygen storage capacity of Ce0. 5 Zr0. 5 O2-Al2 O3 mixed oxides are 51. 8 m2/g higher and 69. 4 μmol/g more than those of Ce0. 5 Zr0. 5 O2 mixed oxides. The ethylbenzene conversion over Ce0. 5 Zr0. 5 O2-Al2 O3 mixed oxides is about 10% higher than that over Ce0. 5 Zr0. 5 O2 mixed oxides after 5 h reaction.%为进一步提高铈锆固溶体储放氧性能,增强乙苯二氧化碳氧化脱氢反应性能,采用共沉淀法合成出氧化铝质量比为50%的铈锆铝氧化物催化剂。通过现代仪器分析表征技术,研究了Al加入对铈锆固溶体复合氧化物晶体结构、储放氧能力的影响。结果表明,Al的加入可起到“扩散阻碍”作用,且有效抑制铈锆固溶体晶粒长大,使得铈锆铝氧化物催化剂比表面积较铈锆固溶体增加了51.8 m2/g,储放氧性OSC值提高了69.4μmol/g,将铈锆铝氧化物催化剂用在乙苯氧化脱氢5 h反应中,发现乙苯转化率提高了10%。