蛋黄-介孔蛋壳结构铁氧化物固体酸纳米反应器的构筑及其降解苯酚机制研究

Low activity, poor stability and inefficient H2O2 utilization of Fenton-like catalyst under neutral condition greatly hinder its wide application. This project adopted hydrothermal synthesis and sol-gel method followed by the subsequent high temperature calcination and chemical etching with SiO2 as template to fabricate yolk-mesoporous shell structured iron oxide solid acid nanoreactor. The mesoporous shell can enhance mass transfer and alleviate Fe leaching during Fenton-like reaction and the inner void can provide abundant space for phenol degradation reaction. Meantime, the iron oxide solid acid in the core can supply suitable acidic microenvironments for Fenton-like reaction and then solve the bottleneck issues faced by traditional catalyst. By studying morphology, surface acidity, electronic structure and its evolution law, the controllable synthesis of large-area yolk-mesoporous shell structured iron oxide solid acid with surface acidity and electronic structure modulation is to be proposed. This project will uncover underlying influence of iron oxide morphology, surface acidity and electronic structure on enhanced adsorption mechanism of phenol and also explore the impact of surface acidity and electronic modulation on H2O2 inherent chemical bond, reactive oxygen species (ROS) production. Finally, the Fenton-like degradation mechanism toward phenol by yolk-mesoporous shell structured iron oxide solid acid is illuminated through physical characterization and theory calculation. This work is in favor of exploring new route in increasing phenol degradation efficiency and developing iron oxide catalytic material with superior performance. The implementation of this project will enrich and improve the Fenton-like reaction theory, and provide new strategies for the design and controlled synthesis of Fenton-like catalysts with high performance.

在中性条件下活性低、稳定性差和H2O2利用率低限制了类Fenton催化剂的广泛应用。本项目以SiO2为模板采用水热-溶胶凝胶法结合后续高温焙烧及化学刻蚀制备蛋黄-介孔蛋壳结构铁氧化物固体酸纳米反应器，通过介孔外壳增强传质、缓解铁溶出，利用内部空腔为反应提供足够空间；而内核铁氧化物固体酸可为反应提供合适的酸性微环境，进而解决催化剂面临的瓶颈问题。研究材料形貌、表面酸性、电子结构及其演变规律，实现大比表面积蛋黄-介孔蛋壳结构铁氧化物固体酸的可控制备及表面酸性、电子结构调控，揭示其对苯酚的吸附增效机制，明确表面酸性、电子结构变化对H2O2内在化学键、活性氧物种产出等的影响规律，结合物理表征和理论计算阐明降解苯酚的反应机制，探索提高苯酚降解效率新途径，研制出高活性、稳定性及H2O2利用率的铁氧化物催化剂。本项目的实施有助于丰富和完善类Fenton反应理论，为构筑高性能催化剂提供突破口和理论依据。

针对多相芬顿催化材料存在的中性条件下活性低、稳定性差以及过氧化氢有效利用率低等瓶颈问题，本项目采取一系列措施如构筑核壳结构催化剂、多组分复合、硫掺杂改性等改善了材料的类芬顿催化活性。通过研究氧化剂含量、催化剂浓度、溶液初始pH等对污染物降解效率的影响，优化了降解工艺；确定了催化剂组成、结构与催化活性间的构效关系；通过物理化学表征、实验与理论计算阐明了催化剂活化双氧水/过一硫酸氢盐的反应机制，并提出了污染物的降解路径，实现了苯酚及抗生素废水的有效降解。本项目的实施可为设计合成高活性与稳定性的铁基催化剂提供指导。