可见光响应的块体TiO_2/GO光催化剂的制备及性能研究

Preparation and Properties of the Visible Light Responsed TiO_2/GO Photocatalysts

用发泡法制备块体光催化材料,可以有效克服目前污水处理过程中需要将光催化材料悬浮在污水中而导致光催化材料回收困难的问题,同时,在块体光催化材料中添加少量氧化石墨烯(Graphene Oxide,GO)可以提高催化剂的效率并拓宽其可见光响应范围。块体光催化材料的制备方法为:按照水与发泡剂体积比为50:1的比例发泡成泡沫,并将泡沫投加到二氧化钛和无机黏结剂的混合物中制成浆状物,无机黏结剂和氧化钛质量比为1:10和1:5两种。将浆状物放入模具中在一定温度下烧结,即可制备出直径和高度均约为1.0 cm的块体光催化材料。研究表明,在煅烧温度为80～500?C时,催化剂中锐钛矿相TiO_2与金红石相TiO_2共存;在400?C时,块体催化剂能够成型,并且具有一定强度。紫外-可见漫反射吸收光谱表明,添加GO的催化剂在可见光区有光谱吸收,同时催化剂颜色由纯白色变为灰白色。将块体催化剂放入自制的反应器中,当催化剂分别为未添加GO、添加1.0%GO和添加2.0%GO(质量分数)样品时,处理后的亚甲基蓝(Methylene Blue,MB)溶液的残留率分别为0.68、0.17和0.08。

The bulk photocatalysts fabricated by foaming method could effectively overcome the existing problem that the photocatalytic materials need to be suspended in the sewage during the photocatalytic reaction, resulting in the photocatalytic materials hard to be recycled. In addition, adding a small amount of graphene oxide (GO) into the photocatalytic materials can improve the efficiency of the catalyst and to broaden its visible response range. The method for preparation of the bulk photocatalytic materials in this work is:Preparing foam in accordance with the volume ratio of water andvesicant 50 : 1, and the foam was added to the titanium dioxide and an inorganic binder to prepare a slurry mixture, with the ratios of titanium dioxide and the inorganic binder 1 : 10 and 1 : 5. The slurry was placed in a mold and fired at a certain temperature, while the bulk photocatalytic materials with the diameter and height both of about 1.0 cm were obtained. Research shows that anatase TiO2 and rutile TiO2 coexist in the photocatalysts with the calcination temperature of 80—500 ±C; At 400 ±C, the bulk catalyst could be formed, and has a certain strength. UV-Vis diffuse reflectance spectroscopy shows that the catalyst added with GO has spectral absorption in the visible region, while the catalyst color changed from pure white to gray.The residual rates of the treatment MB solution were 0.68, 0.17 and 0.08, using the photocatalysts the bulk materials with not added GO,adding 1.0% GO and adding 2.0% GO.