掺硫多孔石墨烯对典型VOCs的光催化性能  

Photocatalytic degradation of typical VOCs on sulfur-doped porous graphene

作　　者：李倩菀 刘彪 敖志敏 Qianyu Li;Biao Liu;Zhimin Ao(Guangzhou Key Laboratory Environmental Catalysis and Pollution Control,Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control,Institute of Environmental Health and Pollution Control,School of Environmental Science and Engineering,Guangdong University of Technology,Guangzhou 510006,China)

机构地区：[1]广东工业大学环境科学与工程学院,环境健康与污染控制研究院,广东省环境催化与健康风险控制重点实验室和广州市环境催化与污染控制重点实验室,广州510006

出　　处：《科学通报》2022年第10期976-985,共10页Chinese Science Bulletin

基　　金：国家自然科学基金(21777033,22176041);广东省科技计划(2017B020216003);广东省教育厅创新团队项目(2017KCXTD012)资助。

摘　　要：燃料燃烧、交通运输、化工生产等过程产生的挥发性有机污染物(volatile organic compounds,VOCs)是导致城市灰霾和光化学烟雾的重要物质.多相光催化反应因条件温和、直接利用太阳光驱动等优点而成为一种理想的VOCs降解技术.本研究采用密度泛函理论,计算掺杂非金属硫原子的单层多孔石墨烯(porous graphene,PG)的光催化性能,包括能带结构、能带边缘位置、分波态密度和前线轨道(highest occupied molecular orbital-lowest unoccupied molecular orbital,HOMO-LUMO)以及它的光学吸收谱,对O_(2)、H_(2)O和VOCs分子的吸附性能等,以探讨光催化降解VOCs的可能性.掺杂硫原子后,PG材料能带的带隙大幅降低,对O_(2)分子的吸附能显著提高,结合能带边缘位置的结果,表明PG材料能产生更多的光生电子,并且提高了产生超氧自由基的能力.对比原始PG材料,硫掺杂PG(S-doped PG)材料的光学响应向红外区偏移,光吸收波长阈值增大,表明硫原子的掺杂大大提高了原始PG材料对可见光的吸收.此外,对VOCs较大的吸附能也表明S-doped PG是一种很有前途的降解VOCs的光催化剂,多维度的计算分析将为多孔石墨烯在光催化中的实际应用提供理论指导.Volatile organic compounds (VOCs),one type of the most harmful pollutants,which mainly from fuel combustion,transportation and chemical industry or other industrial processes,have aroused great concern.Because they are important substances lead to urban haze and photochemical smog,long-term exposure to high concentration of VOCs will stimulate human skin,eyes,and respiratory tract and finally cause a series of diseases even death.Nowadays,a variety of VOCs treatment technologies are available,including biodegradation,combustion,adsorption,and low temperature or photocatalytic oxidation.Among these technologies,the renewable solar-driven multiphase photocatalytic technology has the advantages of rich resources,technical economy,mild reaction conditions,deep mineralized purification,no secondary pollution and so on,becoming an ideal VOCs degradation technology.Due to the large specific surface area and high active center density,semiconductor is often used as a catalyst to realize efficient photocatalysis.Therefore,understanding the performance of semiconductor photocatalyst is of great significance to develop an effective photocatalyst for VOCs degradation from a theoretical perspective.In this study,we calculated the photocatalytic properties of monolayer porous graphene (PG) doped with nonmetallic sulfur using density functional theory (DFT) calculations.The electronic properties of the most stable S-doped PG structure including the energy band structure,the band edge positions,the partial density of states (PDOS),and the highest occupied and the lowest occupied orbitals (HOMO-LUMO) were analyzed first after a comprehensive comparison of doping results.The results manifest that after doping the sulfur atom,the band gap of PG material decreases from 3.050 to 2.127 e V,which is conducive to the generation of more photogenerated electrons in S-doped PG.At the same time,the reduction of band edge position makes S-doped PG improve the ability of superoxide free radical generation than the original PG monolayer.Then,t

关 键 词：多孔石墨烯 光催化降解 硫掺杂 挥发性有机污染物 密度泛函理论 

分 类 号：X701[环境科学与工程—环境工程] O643.36[理学—物理化学] O644.1[理学—化学]