二氧化钛基材料光催化降解VOCs的研究进展

Research advancements in the use of TiO2-based materials for the photocatalytic degradation of volatile organic compounds

  • 摘要: 挥发性有机污染物(VOCs)大量排放导致的人体健康和环境问题已引起广泛关注,如何高效环保地去除VOCs一直是催化化工行业领域的热点和难题之一。光催化氧化技术(PCO)被认为是有效的环境污染物治理方法之一。TiO2作为研究时间最长的光催化剂,具有成本效益高、稳定性好和光催化降解能力强等优点。然而,无法利用可见光和光激发电荷载流子分离效率低等瓶颈问题始终制约着其进一步发展。通过改性来克服TiO2固有限制和提高TiO2光催化氧化降解VOCs能力势在必行,立足于TiO2光催化去除VOCs的基本原理,面向影响光催化反应的关键因素,从掺杂、半导体复合、缺陷工程、晶面工程、载体吸附和形貌调控等几个方面出发对近年TiO2基材料设计及其在光催化降解VOCs领域应用的研究进行了系统的归纳和总结,并对如何进一步改进基于TiO2的光催化氧化VOCs技术提出展望。

     

    Abstract: Human health and environmental concerns caused by the massive volatile organic compound (VOC) emission have attracted widespread attention recently. VOCs are toxic and difficult to eliminate; moreover, they come from a wide variety of sources. Efficient and environmentally friendly removal of VOCs has always been one of the primary concerns in the catalytic chemical industry. Presently, the commonly used methods for VOC removal include absorption−adsorption, biodegradation, thermal catalysis, and membrane separation. However, these methods have several drawbacks, such as high initial investment, expensive materials, high energy consumption, low catalyst efficiency, and incomplete treatment. Photocatalytic oxidation (PCO) technology is considered to be one of the effective methods of environmental pollution control. PCO can directly use solar energy to remove various environmental pollutants. Thus, PCO has inherent advantages such as low consumption, environmental protection, no secondary pollution, and convenience. Photocatalyst is a core step in the PCO process, and as aphotocatalyst studied for the longest time, titanium dioxide (TiO2) has the advantages of high cost-effectiveness, good stability, strong photocatalytic degradation capability, and producing no harmful byproducts. However, bottleneck problems such as the inability to utilize visible light and low separation efficiency of photoexcited charge carriers have always restricted its advancement. Thus, the inherent limitations of TiO2 need to be overcome, and its capability to degrade VOCs via PCO needs to be improved. These modifications can improve the PCO performance through the following mechanisms: (1) By introducing electron trapping levels in the bandgap, which will create some defects in the TiO2 lattice and help trap charge carriers, and (2) by slowing down the electron carrier loading rate to increase VOC degradation. Thus, considering the basic principle of TiO2 photocatalytic removal of VOCs, this study focuses on the key factors affecting the photocatalytic reaction. Beginning with aspects such as metal/nonmetal doping, semiconductor recombination, defect engineering, crystal plane engineering, carrier adsorption, and morphology control, the research on the design of TiO2-based materials and their application in the field of photocatalytic degradation of VOCs in recent years are systematically summarized; moreover, a brief introduction of its control parameters and applications in practical engineering and prospects on how to further improve the use of TiO2-based materials for the PCO technology of VOCs is provided. This review will provide parameter support and optimization suggestions for the research on the degradation of VOCs by TiO2-based photocatalytic materials to help researchers lay the foundation for future research.

     

/

返回文章
返回