采用沉淀法制备了Zr、Cr掺杂的CeO2/Al2O3催化剂,利用BET,XRD,SEM,H2-TPR等技术手段对催化剂进行了表征,考察了CO2气氛下改性催化剂的乙苯氧化脱氢性能.表征结果显示,Cr改性后,催化剂的比表面积明显降低,团聚现象严重,反应后催化剂的积碳率较高,催化剂失活较快;Zr改性后,Zr进入Ce晶格中形成CeO2-ZrO2固溶体,改善了催化剂的烧结现象,催化剂的比表面积和还原性稍有降低,但热稳定性增强,对抑制积碳有积极作用.实验结果表明,Cr最佳负载量为3%(w), Zr最佳负载量为10%(w),Zr改性的催化剂在长时间的反应中具有更好的催化性能.%Zr and Cr doped CeO2/Al2O3catalysts were prepared by a precipitation method. The catalysts were characterized by technical means such as BET,XRD,SEM and H2-TPR,and the performance of the modified catalysts in oxidative dehydrogenation of ethylbenzene with CO2was evaluated. The characterization results showed that the Cr modified catalyst had significantly decreased specific surface area and become seriously agglomerated,and after reaction,the catalyst was relatively high in coke deposition rate,relatively fast in deactivation. Moreover,after modification with Zr,the Zr would enter into Ce lattices to form CeO2-ZrO2solid solution,thereby improving the sintering of the catalyst. Additionally,the catalyst had slightly reduced specific surface area and reducibility and enhanced thermal stability,thus playing a positive role in inhibiting coke deposition. The experimental results showed that the optimal loadings of Zr and Cr were 10%(w) and 3%(w),respectively,and the Zr modified catalyst had better catalytic performance in long-term reaction.
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