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Synthesis of CdS Sensitized TiO2 Photocatalysts: Methylene Blue Adsorption and Enhanced Photocatalytic Activities


Affiliations
1 Department of Chemical and Environmental Engineering, Universiti Putra Malaysia (UPM), 43400 Serdang, Selangor, Malaysia
2 Department of Physics, Universiti Putra Malaysia (UPM), 43400 Serdang, Selangor, Malaysia
 

A series of CdS/TiO2 nanocomposites with different Cd to Ti molar ratio were synthesized from P25-TiO2 nanopowder using microwave-assisted hydrothermal method. The as-produced powders were characterized by XRD, electron microscopy, EDX, and UV-Vis diffuse reflectance spectroscopy. The adsorption capacity and photocatalytic activity of the samples were investigated using methylene blue as a model pollutant. Sorption tests revealed that the adsorption of MB onto the samples obeys the Freundlich- Langmuir isotherm model. The sorption capacity decreased as follows: TiO2 > TCd2 > TCd1 > TCd3 > TCd4. The results of the photocatalytic tests under high-intensity discharge (HID) lamp revealed that CdS/TiO2 powders with low Cd to Ti molar ratios exhibited much higher activities than P25-TiO2. The CdS/TiO2 sample with 20% CdS/(TCd2) showed the most activity among all these samples. The results also show that the Cd to Ti molar ratio of the nanocomposite has a significant effect on the photodegradation of MB and the enhanced activities exhibited by the nanocomposites are because of the low rate of electron-hole recombination.
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  • Synthesis of CdS Sensitized TiO2 Photocatalysts: Methylene Blue Adsorption and Enhanced Photocatalytic Activities

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Authors

A. B. Makama
Department of Chemical and Environmental Engineering, Universiti Putra Malaysia (UPM), 43400 Serdang, Selangor, Malaysia
A. Salmiaton
Department of Chemical and Environmental Engineering, Universiti Putra Malaysia (UPM), 43400 Serdang, Selangor, Malaysia
E. B. Saion
Department of Physics, Universiti Putra Malaysia (UPM), 43400 Serdang, Selangor, Malaysia
T. S. Y. Choong
Department of Chemical and Environmental Engineering, Universiti Putra Malaysia (UPM), 43400 Serdang, Selangor, Malaysia
N. Abdullah
Department of Chemical and Environmental Engineering, Universiti Putra Malaysia (UPM), 43400 Serdang, Selangor, Malaysia

Abstract


A series of CdS/TiO2 nanocomposites with different Cd to Ti molar ratio were synthesized from P25-TiO2 nanopowder using microwave-assisted hydrothermal method. The as-produced powders were characterized by XRD, electron microscopy, EDX, and UV-Vis diffuse reflectance spectroscopy. The adsorption capacity and photocatalytic activity of the samples were investigated using methylene blue as a model pollutant. Sorption tests revealed that the adsorption of MB onto the samples obeys the Freundlich- Langmuir isotherm model. The sorption capacity decreased as follows: TiO2 > TCd2 > TCd1 > TCd3 > TCd4. The results of the photocatalytic tests under high-intensity discharge (HID) lamp revealed that CdS/TiO2 powders with low Cd to Ti molar ratios exhibited much higher activities than P25-TiO2. The CdS/TiO2 sample with 20% CdS/(TCd2) showed the most activity among all these samples. The results also show that the Cd to Ti molar ratio of the nanocomposite has a significant effect on the photodegradation of MB and the enhanced activities exhibited by the nanocomposites are because of the low rate of electron-hole recombination.