Modified Meso-Porous Titania-Sepiolite Clay Composites for Photo Catalytic Reduction of Carbon Dioxide

Titanium dioxide modified by simultaneous doping with Fe, N and S (FNST) and its composites with basic sepiolite clay were synthesized by hydrothermal method. X-ray diffraction (XRD), Diffuse reflectance spectroscopy (DRS), Scanning electron microscopy (SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), N-2 adsorption-desorption isotherms and photo luminescence spectroscopic methods were employed for characterization of the composites. It is observed that triple-doping of TiO2 with Fe, N and S (FNST) induces visible light absorption and also retards recombination rate of charge carriers. The synergetic effect of FNST phase and sepiolite clay matrix influences the efficacy of the composite for photo catalytic reduction of CO2 with water (PCRC). Among the FNST-sepiolite composites studied, 50/50 w/w% FNST/sepiolite composite reduces the recombination rate and further exhibits maximum activity for PCRC. The synergetic effect of FNST and clay structure increases adsorption ability of reactant molecules prolongs life time of charge carriers by trapping, thus increasing photo catalytic activity and facilitating the formation of multi electron reduction products from CO2.