Surface modification of layered perovskite Sr(2)TiO(4) for improved CO(2) photoreduction with H(2)O to CH(4)

Layered perovskite Sr(2)TiO(4) photocatalyst was synthesized by using sol-gel method with citric acid. In order to increase the surface area of layered perovskite Sr(2)TiO(4), and thus to improve its photocatalytic activity for CO(2) reduction, its surface was modified via hydrogen treatment or exfoliation. The physical and chemical properties of the prepared catalysts were characterized by X-ray diffraction, high-resolution transmission electron microscopy, elemental mapping analysis, energy-dispersive X-ray spectroscopy, N(2) adsorption-desorption, UV-Vis spectroscopy, X-ray photoelectron spectroscopy, photoluminescence, and electrophoretic light scattering. CO(2) photoreduction was performed in a closed reactor under 6 W/cm(2) UV irradiation. The gaseous products were analyzed using a gas chromatograph equipped with flame ionization and thermal conductivity detectors. The exfoliated Sr(2)TiO(4) catalyst (E-Sr(2)TiO(4)) exhibited a narrow band gap, a large surface area, and high dispersion. Owing to these advantageous properties, E-Sr(2)TiO(4) photocatalyst showed an excellent catalytic performance for CO(2) photoreduction reaction. The rate of CH(4) production from the photoreduction of CO(2) with H(2)O using E-Sr(2)TiO(4) was about 3431.77 μmol/g(cat) after 8 h.