基于晶面效应锐钛矿型TiO2表界面缺陷调控及光热协同降解VOCs机制

The photothermocatalytic synergetic technology perfectly combines photocatalysis and thermocatalysis together, greatly improving the activity and durability on VOCs purification. Science anatase TiO2 can expose different facets, the interaction between facets and surface/interface defects is different, which is lead to different effect on photothermocatalytic synergetic activity. According to our previous work, we found mechanism on the synergetic photothermocatalysis and the pivotal effect of the interaction between reactant and anatase TiO2 nanosheets with exposed {001} facets on photocatalysis. In this project, we propose to investigate the surface/interface defects turning on anatase TiO2 with exposed different facets are by building defects, supporting Pt, compositing CeO2 and MnO2 etc., in order to obtaining high efficient and well durability anatase TiO2 catalysts and further improvement of the photothermocatalytic synergetic activity. Characterizing by in-situ fourier transform infrared spectroscopy (FTIR), steady-state fluorescence spectra, temperature programmed reduction (TPR) and density functional theory (DFT) calculation etc., we propose to study the effects of surface/interface defects tuning of anatase TiO2 with exposed different facets on the separation efficiency of photogenerated electrons and holes, the reaction of lattice oxygen, photothermocatalytic activity and durability. The interaction between facets and surface/interface defects will be discussed. Determine the contributions of photocatalysis and thermocatalysis in photothermocatalytic synergy. Propose the new mechanism of photothermocatalytic synergetic effect and reveal the mechanism of excellent stability. This project can provide a solution to the key problems of TiO2 photocatalysis for the VOCs purification, such as quick deactivation, low photocatalytic efficiency and low light utilization. Supply novel materials and new mechanism for the promotion of the photothermocatalytic synergetic technology.

光热协同催化技术是将光、热催化有机结合，大幅提高VOCs降解活性和稳定性。TiO2晶面不同与表界面缺陷结构间的相互作用不同，必然对光热协同性能产生不同影响。本项目依据前期发现的光热协同机理及TiO2{001}面与反应物间相互作用对光催化的影响，拟在锐钛矿型TiO2不同晶面上进行缺陷调控，负载Pt，复合CeO2、MnO2等热催化剂，获得高效稳定的TiO2基催化剂，进一步提升光热协同效率。采用原位红外、瞬态荧光、TPR等实验与DFT理论相结合来研究TiO2不同晶面上表界面缺陷调控对光生电子空穴分离效率、晶格氧反应、光热协同性能和稳定性的影响。探讨晶面与缺陷间相互作用；明确光热协同效应中光催化和热催化的贡献量；发展光热协同的新机制，揭示具有优良稳定性的根源。本项目的成功实施将解决TiO2光催化在VOCs治理中易失活、效率低、光能利用率低等关键科学问题，为光热协同催化技术的推广提供新材料、新机制。

光热协同催化技术是将光催化低温反应的优势和热催化治理高浓度有机污染物且稳定性好的优势有机结合，是一种能够高效、稳定降解净化VOCs的新途径。针对解决TiO2光催化在VOCs治理中易失活、效率低、光能利用率低等关键科学问题，本项目提出了基于晶面效应锐钛矿型TiO2表界面缺陷调控及光热协同降解VOCs机制的研究，制备高效、稳定的纳米TiO2催化剂，提高光热协同催化氧化VOCs的效率及稳定性，发展光热协同催化氧化VOCs的新反应机制，具体研究内容包括：通过对锐钛矿型TiO2进行表界面缺陷调控，制备出了高效、稳定的锐钛矿型TiO2基催化剂，包括具有孔洞尺寸能够调控的TiO2空心纳米颗粒，Pt负载在暴露{001}面的锐钛矿型TiO2复合催化剂等；研究了锐钛矿型TiO2表界面缺陷调控对催化剂结构、组成等的影响规律；探索了纳米TiO2催化剂构筑缺陷对催化剂光生电子和空穴分离效率、晶格氧活性的影响；明确了光热协同催化过程中光催化、热催化各自对反应效率的贡献量；对比了锐钛矿型TiO2不同晶面光催化、光热协同催化降解不同种类VOCs的催化活性；阐明了锐钛矿型TiO2表界面缺陷调控对光催化、光热协同催化降解VOCs性能及稳定性的影响规律。制备的Pt/TiO2在全光谱驱动光热协同催化降解8uL苯仅需25min，催化活性是TiO2纳米片的674倍，且具有优异的稳定性，实现高浓度VOCs的高效、稳定降解。发展了光热协同新机理，通过催化剂在全光谱的强吸收，将光能转变为热能，使其表面温度高于热催化起燃温度，实现全光谱驱动高效光热协同催化。将TiO2表界面缺陷调控及光热协同降解VOCs机制扩展到纳米ZnO的研究上，大幅提升纳米ZnO的光催化、光热协同催化降解VOCs的活性。为半导体氧化物催化剂的设计提供了有力的科学依据，为半导体氧化物高效催化净化VOCs的广泛应用提供新的原理。在本项目的资助下，已发表论文共9篇，其中SCI论文4篇，中科院2区及以上3篇，T1高质量科技期刊论文1篇，圆满完成预期目标。