Adsorption of CO2 on C,N-TiO2 Surfaces

Modification of the TiO2 surface by carbon and nitrogen results in the formation of photocatalysts that have high sorption capacity for CO2. The photocatalysts were obtained as follows: approximately 1 g of bare TiO2 was placed in a furnace and kept for 1 hour at a temperature from 100 to 600 degrees C. The sample was first placed under argon atmosphere, following which it was placed under an atmosphere of carbon and nitrogen, achieved by passing ammonia via a washer with n-hexane. This treatment is continued for 1 hour, following which the sample was cooled down to room temperature under argon atmosphere. The photocatalysts thus obtained were characterized by Fourier transform-infrared/diffuse reflectance spectroscopy, UV-Vis/diffuse reflectance, X-ray diffraction and Brunauer, Emmett and Teller surface area measurements. In addition, the zeta potential of the surface of photocatalysts was measured. Sorption tests were conducted in a special reactor using the following conditions: temperature: 20 degrees C, gas flow rate: 100 cm(3)/minute; CO2 concentration: 1000 ppm. Our results show that the best sorbent was TiO2 modified at 100 degrees C for 1 hour. Its sorption capacity amounted to 6.63 mg of CO2 on 1 g of C,N-TiO2 photocatalyst.