单 位：
美国田纳西大学可再生碳中心;中国林业科学研究院木材工业研究所;内蒙古农业大学材料科学与艺术设计学院;国家林业和草原局植物纤维功能材料重点实验室
摘 要：
【目的】为提高二氧化钛(TiO_2)光催化剂净化甲醛气体污染物的能力,利用具有优异光吸收性能和电子转移能力的碳量子点(CDs)掺杂改性TiO_2,可大幅度提高TiO_2光催化性能。【方法】采用3-氨丙基三甲氧基硅烷(APTMS)对亲水性纳米TiO_2进行表面改性,并将禾本植物柳枝稷合成的CDs负载于TiO_2制备了TiO_2-CDs复合光催化木材功能涂层。借助高分辨透射电子显微镜、红外光谱、热重分析、紫外可见光光谱、荧光光谱等表征手段对CDs及其负载TiO_2复合光催化剂进行表征,并以甲醛气体作为模拟污染物进行光催化降解实验。【结果】合成的CDs粒径尺寸为3～6 nm,表现为较好的石墨相结构,且CDs光致发光具有一定的激发依赖性。CDs功能化TiO_2复合材料不仅在紫外光区域有较强的吸收,而且在400～500 nm波长范围内具有更宽的吸收带,CDs负载TiO_2光催化涂层分别在紫外光源与紫外结合可见光源条件下对甲醛气体的净化效率达到68.26%和81.63%,较未改性的TiO_2木材涂层提高了35.55%和38.71%,同时TiO_2-CDs木材涂层可显著降低木材表面润湿性,其表面水接触角为96.4°,较对照组木材(62.5°)提升了54.24%。表面涂饰对木材表观颜色影响较小,TiO_2-CDs净醛功能化木材的表面亮度较对照组木材轻微降低了5.22%,表面色差较对照组为11.03。此外,TiO_2-CDs木材涂层具有优良的可重复使用性能,相比第一次循环,7次循环后试样对甲醛气体的降解效率仅分别下降了3.54%和2.56%。【结论】CDs掺杂功能化可拓宽TiO_2光催化剂在可见光区域净化甲醛气体污染物的能力,同时改善木材表面润湿性,且对木材表观颜色影响较小,对于开发具有净化室内甲醛气体污染物功能的木质材料意义重大。
译 名：
Preparation of wood functional coatings with carbon dots grafted TiO_2 for its photocatalytic degradation of formaldehyde gas
作 者：
Zhang Longfei;Hairihan;Wang Siqun;Chen Zhilin;Wang Yamei;Research Institute of Wood Industry, Chinese Academy of Forestry;National Forestry and Grassland Administration Key Laboratory of Plant Fiber Functional Materials;College of Materials Science and Art and Design, Inner Mongolia Agricultural University;Center for Renewable Carbon, University of Tennessee;
关键词：
carbon dot;;titanium dioxide;;formaldehyde;;photocatalysis
摘 要：
[Objective]In order to broaden the photocatalytic degradation ability of titanium dioxide (TiO_2)for formaldehyde gas pollutants,carbon dots (CDs) with excellent light absorption and electron transfer were used to modify the TiO_2,which greatly improves the performance of pure TiO_2 photocatalyst.[Method]The surface of TiO_2 nanoparticles was modified by (3-aminopropyl) trimethoxysilane (APTMS)and integrated with CDs,which was synthesized from plant biomass of switchgrass.The resulted TiO_2-CDs composites were then coated on wood to construct a photocatalytic coating.Multiple characterizations such as high-resolution transmission electron microscopy (HRTEM),infrared spectroscopy (FTIR),thermogravimetric analysis (TG),ultraviolet-visible spectroscopy (UV-Vis),fluorescence spectroscopy were applied to characterize the CDs and their loading TiO_2 photocatalysts.The photocatalytic experiments were also carried out with formaldehyde gas as a typical pollutant.[Result]The synthesized fluorescent CDs had a good graphite phase structure with a particle size of 3-6 nm,which also showed strong excitation dependence.TiO_2-CDs composites not only had strong absorption under UV light,but also had a wider absorption band in the wavelength range of 400-500 nm.TiO_2-CDs wood coatings can achieve 68.26%and81.63%degradation efficiency of formaldehyde gas under UV light and UV combined with visible light source,which was 35.55%and 38.71%higher than that of unmodified TiO_2 coating under the same condition.In addition,TiO_2-CDs coating significantly reduced the wettability of wood surface with a water contact angle of 96.4°,which was 54.24%higher than that of the pure wood (62.5°).Moreover,surface coating had little effect on the apparent color of wood.Surface brightness of functional wood was slightly lower than that of the pure wood by 5.22%,and the color difference was only 11.03 compared with the uncoated wood.Furthermore,the TiO_2-CDs photocatalytic wood coating showed good recyclability with a degradation efficiency decrease of 2.56%and 3.54%,respectively after 7 cycles.[Conclusion]The utilization of CDs doping could broaden the degradation ability of formaldehyde gas for TiO_2 photocatalyst in the visible light region,reduce the wettability of wood surface and has little effect on the apparent color of wood,which would be useful for the development of wood functional materials for degradation of formaldehyde gas pollutants.
