Photocatalytic Improvement under Visible Light in TiO2 Nanoparticles by Carbon Nanotube Incorporation

Abstract

Photocatalytic activity of TiO2 nanoparticles was successfully enhanced by addition of multiwall carbon nanotubes (MWCNT) to make CNT/TiO2 nanocomposites by sol-gel method at ambient temperature. CNT treated by HNO3: H2SO4 treatment (1: 3 v/v) was mixed with TiO2 nanoparticles at various molar ratios and calcination temperatures. The optimal molar ratio of CNT: TiO2 was found at 0.05: 1 by weight. The optimal calcination condition was 400°C for 3 h. From the results, the photocatalytic activities of CNT/TiO2 nanocomposites were determined by the decolorization of 1 × 10-5 M methylene blue (MB) under visible light. CNT/TiO2 nanocomposites could enhance the photocatalytic activity and showed faster for the degradation of MB with only 90 min. The degradation efficiency of the MB solution with CNT/TiO2 nanocomposite achieved 70% which was higher than that with pristine TiO2 (22%). This could be explained that CNT prevents TiO2 from its agglomeration which could further enhance electron transfer in the composites. In addition, CNT/TiO2 nanocomposites had high specific surface area (202 m2/g) which is very promising for utilization as a photocatalyst for environmental applications.