Enhancement of Photocatalytic Activity of TiO₂ Thin Film Using Diethanolamine and MCM-41

Abstract

TiO2thin film enhanced by diethanolamine (DEA) and MCM-41 (D-TiO2/MCM-41) was successfully synthesized by sol-gel dip coating technique on glass slides. The roles of DEA and MCM-41 on physical and photocatalytic characteristics of the films were studied using various techniques such as x-ray defraction (XRD), fourier transform infrared spectroscopy (FTIR), ultra violet-visible (UV-Vis) spectrometry, Brunauer, Emmett and Teller (BET) surface area analysis and field emission scanning electron microscope (FESEM). The XRD results showed that the thin film contained almost 100% anatase phase and the crystal size of TiO2was in the range of 4-8 nm. The FTIR spectra indicated the formation of Ti-O-Si and Si-O-Si linkages due to interaction of TiO2and MCM-41. The surface area of TiO2was increased significantly when MCM-41 was added. The use DEA and MCM-41 caused slight increase in visible light absorption but UV absorption was decreased. The photocatalytic reactivity of the thin film was tested by photocatalytic degradation of methylene blue under visible light. The addition of DEA as a nitrogen source was beneficial not only for obtaining stable/smooth surface of the thin film but also for enhancing photocatalysis of methylene blue by preventing charge carrier recombination. While MCM-41 played important functions in improving porosity and hydrophilicity of the film. The photodegradation of methylene blue was obtained up to 35% of its original concentration when 1M DEA and 0.3M MCM-41 were incorporated in TiO2thin film. The overall enhancement of photocatalytic activity of the film was a result of nitrogen doping, increased surface area as well as increased hydrophilicity provided by MCM-41.

Enhanced Photodegradation of p-Nitrobenzoic Acid by Binary Mixtures with Ba2+/TiO2 and MCM-41

“…The XPS spectrum of the Si 2p includes two peaks located at 102.8 and 102.2 eV that are attributed to the Si–O–Si and Ti–O–Si linkages [ 33 ]. This evidence confirms that Ti 4+ in a titania octahedral lattice can be replaced by Si 4+ , and vice versa [ 34 , 35 ]. The XPS spectrum of the O 1s comprises several peaks in the regions from 528 to 537 eV.…”