开发高效、廉价、稳定的光催化材料是光催化技术得以广泛应用的基础和核心。TiO₂由于高化学稳定性、耐化学污染物和环境友好性等优点而被广泛研究。然而，宽带隙、易聚集、电子-空穴对高复合以及悬浮于溶液中难回收限制了其应用。本论文基于强吸附性海泡石为载体，负载高活性TiO₂纳米晶形成TiO₂/海泡石复合材料。海泡石负载解决纳米TiO₂固液难分离及聚集问题；其辅助晶面调控协同增效下可促进电子-空穴分离；通过表面等离子体共振(SPR)效应进一步优化可见光催化性能。同时，研究材料化学组成、元素价态、孔结构及形貌等与催化性能的构效关系，探讨光降解机理。本论文主要研究内容如下： (1)以改性海泡石(MS)为载体，水解沉淀法制备微介孔结构TiO₂/海泡石(TiMS)复合材料。研究了锻烧温度、TiO₂/MS重量比、甲醛初始浓度、环境湿度等因素对TiMS降解HCHO的影响。证明了海泡石负载能改善TiO₂的光催化效率和稳定性，探讨了 TiMS吸附和光催化降解HCHO协同增强机制。 (2)基于海泡石负载和晶面调控的思路，以一步溶剂热法合成{001}和{101}面共同暴露的单晶TiO₂/海泡石复合凝胶(TiSG)。研究了 CTAB含量、溶剂热温度/时间、醋酸含量等对TiO₂晶面暴露及形貌的影响，提出了TiSG可能形成机制。CTAB为晶面调控剂与高活性(001)面强烈结合，缓解热力学有利的(001)面生长，通过调控<001>和<101>方向的生长速率获得去顶双锥体TiO₂单晶。海泡石纤维通过交联机理发生自组装，形成层状纤维网络结构，进而凝胶化形成三维(3D)复合凝胶。TiSG与TiO₂、P25相比具有更高催化活性，这归因于3D凝胶结构有利于光的折射和反射，显著改善光的利用率；(001)和(101)面的晶面异质结促进了电子-空穴对有效分离；海泡石负载增大比表面和吸附能力。 (3)通过溶剂热法控制钛源和醋酸浓度，制备高活性介晶TiO₂/海泡石复合材料。介晶TiO₂是由[001]取向的锐钛矿纳米单晶自组装而成。调控反应时间、海泡石含量等参数，优化其光催化性能。阐述甲基橙(MO)和亚甲基蓝(MB)光降解机制的差异，这与材料表面带电荷情况和光催化过程中关键活性物种有关。 (4)为优化可见光催化性能，采用矿物负载辅助SPR效应制备一种新型三元Ag修饰的TiO₂/海泡石(AgTiS)复合材料。与TiO₂、P25、海泡石和TiO₂/海泡石相比，AgTiS具有增强的可见光催化活性。降解动力学表现伪一级行为。空穴和超氧自由基是光降解MO的关键活性物种。基于海泡石和Ag作用，探讨AgTiS在促进可见光捕获及改善光生电荷分离效率方面的增强机理。 关键词：TiO₂/海泡石；溶剂热法；晶面调控；矿物载体；光催化

 The development of efficient, inexpensive, and stable photocatalytic materials is the basis and core for the widespread application of photocatalytic technology. TiO₂ has been extensively studied due to its high chemical stability, chemical resistance and environmental friendliness. However, wide band gaps, ease of aggregation, high recombination of electron-hole pairs, and difficulty in separating TiO₂ powder suspended in solution limit its application. In this paper, the combination of sepiolite with excellent adsorption properties and high phocatalytic activity of TiO₂ nanocrystals to form TiO₂/sepiolite composite solves the above problems. The TiO₂ nanoparticles can be embedded in the sepiolite, which could improve the problems of solid-liquid separation and easy aggregation of nano-TiO₂; and electron-hole separation was further promoted by the crystal plane modulation of the supported TiO₂.The visible photocatalytic activity was further enhanced by the surface plasmon resonance (SPR) effect. At the same time, the structure-effect relationship between chemical composition, elemental valence, pore structure, morphology and phtocatalytic properties of the material was studied. The photodegradation mechanism was further discussed. The specific research contents of this paper are as follows: (1)Micro-mesoporous structure TiO₂/sepiolite (TiMS) composites were prepared by hydrolysis-precipitation method using modified sepiolite (MS) as carrier. The effects of calcination temperature, TiO₂/MS weight ratio, HCHO initial concentration and environmental relative humidity on the degradation of HCHO by TiMS were studied. It was proved that the presence of sepiolite can improve the photocatalytic efficiency and stability of nano-TiO₂,and the photocatalytic mechanism of TiMS for degradation of HCHO was finally proposed. (2)The single-crystal TiO₂/sepiolite composite gel (TiSG) with exposed {001} and {101} facets was synthesized by one-step solvothermal method. The CTAB content, solvothermal temperature, solvothermal time, and HAc content played crucial roles in the morphological and exposed facet of TiSG. A possible mechanism for the formation of TiSG was further proposed. CTAB as capping/shape-controlling agent can strongly bind to the more reactive (001) facet of TiO₂ and then mitigate the thermodynamically favored (001) plane growth. Eventually, the truncated octahedral TiO₂ was obtained by controlling the growth rates in <001> and <101> directions. Sepiolite as a cross-linking agent provided sufficient crosslinking sites for TiO₂ to induce three-dimensional (3D) network formation, thereby generating the composite gel. TiSG exhibited higher catalytic activity than TiO₂ and P25 for the following reasons. The 3D network structure is advantageous to light reflection and refraction, which can greatly improve the utilization rate of light; The surface heterojunction between (001) and (101) planes is formed, which promotes separation of photoexcited electrons and holes; The presence of sepiolite increases the specific surface area and adsorption capacity of the material. (3)High activity mesocrystalline TiO₂/sepiolite (TiS) composites were prepared by controlling the titanium source and acetic acid concentration.via a solvothermal process. Thereinto each TiO₂ mesocrystal comprised many [001]-oriented anatase nano single crystals. The parameters such as reaction time and sepiolite content were adjusted to optimize the photocatalytic activity of TiS. The differences in the photocatalytic degradation mechanisms of MO and MB were described, which was related to the charge of the surface of the material and the main active species in the photocatalytic process. (4)To optimize the visible light catalytic performance, a novel ternary Ag-decorated TiO₂/sepiolite (AgTiS) composite was prepared by sepiolite loading-assisted SPR technology. Compared with TiO₂, P25, sepiolite and TiO₂/sepiolite, the designed AgTiS exhibits enhanced visible light catalytic activity. The degradation kinetics exhibit pseudo-first-order behavior. Holes and superoxide radicals are the main active species in the photodegradation of MO. Based on the role of sepiolite and Ag, the possible photocatalytic mechanism of AgTiS composites was proposed under visible light. Keywords: TiO₂/sepiolite,Solvothermal method, Crystal facets modulation, Mineral carrier, Photocatalysis