高性能IrO2/CeO2-ZrO2甲烷燃烧催化剂的设计合成及构效关系研究

The oil field associated gas contains low-concentration methane, which will cause the environmental pollution if released directly. Among the technologies developed for the clean and effective utilization of low-concentration methane, the catalytic combustion process is considered as the most promising approach, the key is to develop high efficient catalysts. Nowadays, the common used catalysts for this reaction are noble metals such as Pt and Pd. However, these noble metals generally suffer from the low hydrothermal stability and poor sulfur-resisting performance. To solve these problems, we plan to prepare the CeO2-ZrO2 solid solution as supports through the homogeneous emulsion method and the stabilizer doping strategy. The CeO2-ZrO2 solid solution with high surface area and high stability is benefit for the dispersion of active component IrO2, which may endow the resulting IrO2/CeO2-ZrO2 with high performance for the catalytic combustion of methane. With the various advanced characterizations, we aim to reveal the influence rules of the homogeneous emulsion preprocessing and stabilizer doping on the precursor of CeO2-ZrO2 solid solution. Moreover, we will make effort to establish new methods for the control of the thermal stability and oxygen vacancy of CeO2-ZrO2 solid solution. Finally, the synergistic mechanism between the active component IrO2 and the CeO2-ZrO2 solid solution will also be investigated and elucidated. The achieved findings will provide a technical source for the clean and effective utilization of low-concentration methane under dynamic conditions.

含有较低浓度甲烷的油田伴生尾气直接排放严重污染环境，利用甲烷催化燃烧技术实现低浓度甲烷的清洁高效利用是最有效手段，其关键是开发出高性能的甲烷燃烧催化剂。本项目针对现行Pt、Pd等贵金属基催化剂水热稳定性和抗硫性能不足的难题，拟利用均质乳化技术和掺杂稳定剂的方法设计制备出高比表面积、高稳定性的CeO2-ZrO2固溶体载体；并以IrO2为活性组分，设计制备出高性能的IrO2/CeO2-ZrO2甲烷燃烧催化剂。利用各种先进的表征手段，揭示均质乳化预处理和稳定剂掺杂对铈锆固溶体前驱物的影响规律，建立铈锆固溶体的热稳定性与氧空位的调变方法，阐明活性组分IrO2与CeO2-ZrO2固溶体之间的协同作用机制，为适应动态环境条件下的低浓度CH4清洁高效利用提供技术源头。

项目针对油田伴生尾气等低浓度甲烷治理体系所需，提出了开展高性能Ir基甲烷燃烧催化剂的设计合成。基于载体形貌、表面性质和组成与活性组分IrOx.前驱体的调变策略，开展了研究工作。采用现代物化手段表征，初步阐明了Ir基催化剂的活性组分与载体之间的协同机制，以及催化剂的微观结构与催化活性间的相关性及其甲烷氧化反应的催化机理。制备出不同系列的适应高空速、低空燃比气氛的Ir基催化剂，而且较好地解决了催化剂抗水性问题。Ir/ZrO2-SO42-催化剂在50,000 mL∙h-1∙gcat -1空速下甲烷完全转化温度的T90%为380 ºC；在体系中含10%H2O条件下，450 ºC 甲烷转化率稳定在90%。Ir/TiO2–ZrO2催化剂的性能与之相近，T90%为388 ºC。鉴于Ir价格攀升近5倍，同时着力于非铱基催化剂的研究。项目研究为低浓度甲烷燃烧催化剂的开发奠定了理论基础，并为Ir基、Pd基、Co基尖晶石以及ZrO2等纳米催化材料的合成改性提供具有参考价值的规律和参数。