宽带隙金属氧化物材料光催化降解苯系物:反应机理和改性策略

Photocatalytic Degradation for Benzene Series in Wide-band Gap Metal Oxide:Reaction Mechanism and Modification Strategies

苯系物广泛存在于水体和大气环境中,难降解和高毒性的特点使其对人体健康和生态环境产生严重威胁。光催化技术因具有反应条件温和、氧化还原能力强、绿色无二次污染等特点而备受关注,可用于污染物降解、能源转化,尤其对于难降解苯系物的治理具有显著优势。宽带隙光催化剂具有价带位置更正、氧化能力强、光化学稳定性高和造价低等特性,在苯系物降解中发挥了重要作用,被广泛应用于苯系物等难降解污染物的治理。但宽带隙光催化剂光响应范围有限、表面电势高和光生电子空穴对难以分离等特点,限制了其在实际治理工艺中的应用。另外,苯系物种类繁多、结构复杂,以及当前原位表征技术尚未普及等因素,导致对苯系物的转化机理和开环机理的认识不足,制约了高效治理苯系物光催化剂的设计制备和光催化技术在治理苯系物方面的实际应用。基于以上问题,本文围绕宽带隙光催化氧化技术在苯系物降解中的重要进展,介绍了光催化降解苯系物的反应机理、宽带隙半导体性能影响因素,总结了宽带隙光催化剂改性策略的最新进展并分析了其形成机制和促进光催化苯系物降解的作用机理,最后针对宽带隙光催化剂降解反应机理的研究、提高降解效率和实际应用等方面提出了展望。

Benzene compounds are widely present in water bodies and atmospheric environments,and their refractory and highly toxic characteristics pose a serious threat to human health and the ecological environment.Photocatalytic technology has attracted much attention in pollutant degradation and energy conversion because of mild reaction conditions,strong redox ability,and green and no secondary pollution,especially for the treatment of refractory benzene series.The advantages of positive valence band position,strong oxidation ability,high photochemistry stability and lower cost on wide-band gap photocatalysts play important role in benzene series degradation.However,wide band gap photocatalysts have limited photo-response range,higher surface potential and difficult separation of photo-generated electron-hole pairs,which limit their application in actual treatment processes.In addition,the effects of wide variety of benzene series,complex structure,and the current in-situ characterization technology limited the understanding of the conversion and ring opening mechanism of benzene series.That restricts the design and preparation for efficient photocatalysts and photocatalytic technology for the practical application in benzene treatment.This review focuses on the important progress about wide-band gap photocatalytic oxidation technology in the degradation of benzene series,and introduces the latest developments about the reaction mechanism of photocatalytic benzene series degradation,the performance influencing factors of wide-band gap semiconductors,and the modification strategies on wide-band gap semiconductors.Finally,the prospects in reaction mechanism research,degradation efficiency enhancement and practical application are put forward.