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

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.