TiO_2/SiO_2复合纳米纤维的GQDs改性及其对甲醛的可见光催化降解性能

GQDs Modified TiO_2/SiO_2 Composite Nanofibers and Its Photocatalytic Activity for Degradation of Formaldehyde

采用静电纺丝法合成了TiO_2/SiO_2柔性复合纳米纤维膜,而后对其进行石墨烯量子点(GQDs)改性,制备了GQDs/TiO_2-SiO_2复合纳米纤维,其中GQDs用水热法合成。用X射线衍射仪(XRD)、电子万能材料试验机、扫描电子显微镜(SEM)、紫外-可见分光光度计(UV-Vis)对其物相组成、力学性能、微观形貌以及光催化性能进行了表征。结果表明:尺寸在7 nm^15 nm之间的GQDs松散沉积在直径为200 nm^400 nm的TiO_2/SiO_2纳米纤维上,纤维连续性好,复合薄膜有较好的力学性能;TiO_2的结晶较好,为锐钛矿相;GQDs复合后将TiO_2的本征吸收从390 nm左右延伸到了420 nm左右,拓宽了TiO_2的吸收范围。在可见光催化降解中,初始浓度为0.32 mg/m^3的甲醛气体110 min后的降解效率达到70%。

TiO2/SiO2 flexible nanofibers were prepared by electrospinning methods and then were modified with graphene quantum dots （GQDs）, which were synthesized by hydrothermal method. The phase composition, mechanical property, microstructure and photocatalytic activity of the obtained GQDs/TiO2-SiO2 composite nanofiber membranes were characterized by X-ray diffraction （XRD）, electronic universal testing machine, scanning electron microscope （SEM） and ultraviolet-visible spectrophotometer（UV-Vis）. The results showed that TiO2/SiO2 nanofibers were uniform, and the diameters were around 200 nm ~ 400 nm. The sizes of GQDs were 7 nm ~ 15 nm and GQDs were deposited on the the surface of TiO2/SiO2 nanofibers loosely. GQDs/TiO2-SiO2 composite nanofiber membranes had good mechanical properties. TiO2 was anatase phase and possessed good crystallinity. The intrinsic absorded spectrum edge of TiO2 was extended from 390 nm to 420 nm after the modifying of GQDs with TiO2/SiO2 nanfibers. The degradation efficiency could reach 70% in 110 min under visible light irradiation, when the initial concentrationof gas formaldehyde was 0.32 mg/m3.