Effect of carboxyl group on the visible-light photocatalytic activity of SrTiO3 nanoparticles

SrTiO3 nanoparticles modified with a carboxyl group were successfully prepared by microwave-assisted solvothermal reaction of SrCl2·6H2O and Ti(OC3H7)4 in methanol–organic acid solution. The as-prepared products were characterized using X-ray diffraction (XRD), diffuse reflectance spectroscopy, and Fourier-transform infrared (FTIR) spectroscopy. The photocatalytic activity was determined by DeNO x ability using a mercury arc with filters to control irradiation wavelengths to >290, >400, and >510 nm. Nanoparticles of perovskite-type SrTiO3 were successfully synthesized above pH 12. The photocatalytic activity of SrTiO3 under visible-light (>510 nm) irradiation could be promoted by surface modification of SrTiO3 with the carboxyl group (–COO), especially from oleic acid.