Structure and photocatalytic activity of maleic anhydride-functionalized TiO2 nanoparticles by a simple method

摘要

Titanium dioxide (TiO2) nanoparticles were functionalized with maleic anhydride (MA). The extension of adsorbed MA on the TiO2 was evaluated by ultrasonic and magnetic stirring. Total Organic Carbon and Thermogravimetric Analysis confirmed the presence of surface MA even after the washing process. The Fourier Transform Infrared and UV-Vis Diffuse Reflectance spectra clearly showed the chemical anchored maleic anhydride on the TiO2 surface as bidentate bridging adsorption. The surface modification of TiO2 extended its light absorption range to the visible light region reducing its bandgap energy from 3.05 to 2.55 eV. X-Ray Diffraction patterns showed that the TiO2 functionalized presented a mixture of anatase and rutile phases without any crystalline phase transformation after MA chemisorption process. The functionalization percentage and the reaction efficiency for the TiO2 with 5 wt% MA sample were 3.6 and 69%, respectively, as shown by Differential Thermal Analysis and Thermogravimetric Analysis. The performance of pure and functionalized TiO2 samples were evaluated in the photocatalytic degradation of the Methyl Orange dye under ultraviolet light. TiO2 with 5 wt% MA produced a maximum degradation of 97% after 90 min, 3% higher than the commercial TiO2.