Black TiO2 and graphene oxide (GO) have attracted intensive attention as an effective catalyst on visible light driven for photodegrading of dyes. In this study, nano-black TiO2 was prepared by a simple hydrogenation of the anatase titanium oxide, and the graphene oxide was prepared by applying the modified Hummers method. The diffuse reflectance spectroscopy has been investigated to find out the optical energy gaps of the treated and nano-black samples. The prepared powders and nanofiber membranes are carefully examined to ensure their single phase and compound structure formation as well as to measure the equivalent crystallite size and particle distributions. The optimum degradation efficiency of malachite green and methylene blue dyes occurred at pH values of 8 and 10, respectively. The maximum photocatalytic degradation efficiencies of malachite green (MG) and methylene blue (MB) were found to be 74 and 39%, respectively, under visible light after 30 min. The degradation efficiency of MG is peaked at pH 8 and 20 mg of the nano-black TiO2. The stability and flexibility of the nanofibers allow their application in a continuous system and can be reused after several cycles.
Keywords: Black-TiO2; Graphene oxide; Optical energy bands; Photocatalytic activity; Redox reaction mechanism; Water treatment.