Photocatalytic Deacon Reaction Over Srtio3

SrTiO3 was prepared by a polymeric precursor method and applied in the photocatalytic aerobic oxidation of HCl in a flat-plate reactor equipped with a UV LED array (368 nm). Reaction rates up to 240 mmol h(-1) m(-2) and apparent quantum yields up to 33% using an illuminated area of 60 cm(-2) were achieved with highly crystalline SrTiO3 calcined at 750 degrees C, outperforming commercially available SrTiO3 by a factor of almost 2. A gradual catalyst deactivation was observed, which was due to the formation of crystalline SrCl(2)x2 H2O on the surface confirmed by X-ray diffraction, electron microscopy and X-ray photoelectron spectroscopy (XPS). Increasing the HCl partial pressure accelerated both Cl-2 formation and catalyst deactivation. XP spectra revealed an intrinsic surface segregation of Sr and the presence of several Sr- or O-containing surface species. High Cl-2 yields up to 42% obtained with an illuminated area of 120 cm(-2) encourage further research on a photocatalytic Deacon process for improved HCl recycling.