TiO₂ supported one-dimensional low silica zeolite for the high- efficiency production of pure methane via Photocatalytic reduction of CO₂ gas

Due to the depletion of crude oil, scientists must search for a renewable source of energy. Photocatalytic reduction of CO2 to methane gas as a hydrocarbon fuel seems to be a promising technique to produce solar fuel and reduce global warming for improved sustainability. A gas flow reactor was made from a quartz tube packed with TiO2 thin-film deposited on different substrates; one dimensional zeolite beads and glass sheets. At ambient temperature, TiO2 was prepared by the Sol-Gel method using ethylenediaminetetraacetic acid (EDTA) as a precipitating agent. The effect of calcination temperature was also studied at different temperatures: 200, 400, and 550 & DEG;C. TiO2-supported one-dimensional zeolite was characterized by X-Ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and FT-IR and Raman spectroscopy. The prepared materials were used in the photocatalytic reduction of CO2 (5 ml/min flow rate) in the presence of water vapor at 80 & DEG;C using a simple gas flow reactor (20 cm in length and 2.5 cm in diameter). The gaseous products were analyzed by gas chromatography. The analysis confirmed the production of pure methane gas. The highest yield of CH4 gas was achieved after four hours of irradiation with a continuous flow of CO2 gas. The maximum concentration of methane was 1404 ppm using TiO2/zeolite calcined at 550oC. The results were compared with those of unsupported TiO2 prepared under the same conditions. The order of activity was TiO2/Z 550 >TiO2/Z 400 >TiO2/Z 200T > TiO2/glass sheets > TiO2 powder.