MoS2/g-C3N4纳米纤维光催化降解柴油机苯系排放污染物

采用同轴静电纺丝法制备了MoS_2/g-C_3N_4纳米纤维,采用XRD、FTIR、XPS、UV-Vis和Raman等光谱分析技术表征了催化剂相组成和微观形貌,评价了催化剂表面化学形态和吸光特性,探讨了催化剂对甲苯的光催化降解机理,研究了MoS_2含量、光源条件、温度和催化稳定性对降解甲苯的影响规律.结果表明,在MoS_2/g-C_3N_4中掺杂适宜的MoS_2有助于提高催化剂活性,改善催化剂比表面积和孔容积.在可见光条件下,催化剂(10%MoS_2)对甲苯的降解率为90.24%.由汽车尾气中苯系污染物光催化降解应用可知,在柴油机转速为2000 r·min~(-1),油门开度(负荷)分别为25%、50%、75%和100%的条件下,10%MoS_2对苯、甲苯、乙苯、对二甲苯、间二甲苯和邻二甲苯的平均降解率分别为88.12%、90.03%、86.25%、87.12%、87.07%和87.23%,表明MoS_2/g-C_3N_4纳米纤维具有较强的光催化降解苯系物能力.

Photocatalytic degradation of benzene homologues in diesel engine by MoS2/g-C3N4 nanofibers

MoS₂/g-C₃N₄ composite nanofibers were prepared by the coaxial electrospinning method. The crystalline phase and microstructure of MoS₂/g-C₃N₄ catalysts were displayed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Absorption characteristics and electrochemical properties of MoS₂/g-C₃N₄ catalysts were characterized by X-ray photoelectron spectroscopy (XPS), ultraviolet-visible spectrometry (UV-Vis) and Raman spectroscopy. The corresponding influence factors on MoS₂ content, light condition, temperature and repeated performance for toluene degradation rate in the photocatalytic activity device were analyzed. The results show that catalytic activity of MoS₂/g-C₃N₄ was improved through doping appropriate amount of MoS₂, and the specific surface area and pore volume of catalysts increased accordingly. with 10% MoS₂, MoS₂/g-C₃N₄ presented 90.24% photocatalytic degradation effieincy for toluene in visible-light illumination. Under four different loads (25%, 50%, 75% and 100%) and diesel engine rotational speed (2000 r·min^-1), average degradation rate of benzene, toluene, ethylbenzene, p-xylene, m-xylene and o-xylene were 88.12%, 90.03%, 86.25%, 87.12%, 87.07% and 87.23% respectively in visible-light illumination. Therefore, it is verified that MoS₂/g-C₃N₄ catalyst had better photocatalytic activity in reducing benzene homologues emissions from diesel engine exhaust.