不同碳链长度的表面活性剂对CeO_(2)-ZrO_(2)-Y_(2)O_(3)-La_(2)O_(3)材料性能的影响

The Effect of Surfactants with Different Carbon Chain Lengths on the Properties of CeO_(2)-ZrO_(2)-Y_(2)O_(3)-La_(2)O_(3) Materials

研究分析不同碳链长度的烷基酸表面活性剂(十酸、十二酸、十四酸、十六酸、十八酸)对CeO_(2)-ZrO_(2)-Y_(2)O_(3)-La_(2)O(3 CZ)材料性能的影响规律,揭示表面活性剂在构筑高性能CZ材料中的作用机制。N2-吸/脱附、OSC、H2-TPR和催化剂三效活性等测试结果表明,在纳米晶成核阶段加入不同碳链长度的表面活性剂均可在一定程度上增大纳米晶的初始晶粒尺寸,由此降低纳米晶的烧结驱动力。表面活性剂的引入促进材料产生更多氧空位从而提高了其氧化还原性能,其中,十二酸对材料热稳定性和氧化还原性能的促进效果最优,所制备CZ材料高温老化后的比表面积损失率低至46.3%,还原峰温最低为497℃,Ce的利用率最高为39%,因而其负载的单Pd三效催化剂表现出最佳的催化活性。

The effects of alkyl acid surfactants with different carbon chain lengths(decanoic acid,dodecanoic acid,tetradecanoic acid,hexadecanoic acid,octadecanoic acid)on the properties of CeO_(2)-ZrO_(2)-Y_(2)O_(3)-La_(2)O_(3)(CZ)materials were studied and analyzed,and the underlying mechanism of surfactants in building high performance CZ materials has also been revealed.The results of N2-adsorption/desorption,OSC,H2-TPR,and catalyst activity show that the addition of all surfactants with different carbon chain lengths during the nucleation stage of nanocrystals can increase the initial grain size of nanocrystals,thereby reducing the driving force of sintering.At the same time,the introduction of surfactants produces more oxygen vacancies in the material,thereby improving its redox performance.Among them,dodecanoic acid plays the most prominent effects improving the thermal stability and redox performance of CZ materials,the resultant CZ exhibits the lowest loss rate of specific surface area of 46.3%,the lowest reduction peak temperature of 497℃,the highest utilization rate of Ce of 39%,and consequently the best catalytic activity of its supported Pd-only TWC.