Facile synthesis of Ag2O-TiO2/sepiolite composites with enhanced visible-light photocatalytic properties

Ag2O-TiO2/sepiolite heterostructure composites were synthesized by a simple two-step method at low temperatures (100–450 °C). Acid red G aqueous solution and gaseous formaldehyde were chosen as model organic pollutants to evaluate the photocatalytic performance of the as-prepared composites. The results showed that the Ag2O-TiO2/sepiolite exhibited enhanced photocatalytic activity over pure Ag2O-TiO2, TiO2/sepiolite, and Ag2O/sepiolite under visible-light irradiation (λ > 420 nm). The excellent photocatalytic efficiency of these composites can be ascribed to the synergistic effect between the heterojunction and the porous structure of the clay layers, which induced high adsorption and efficient charge separation. In addition, the active species involved in the degradation reaction have been investigated by photoluminescence spectroscopy and quenching experiments. A possible photocatalytic degradation mechanism of acid red G dye by the Ag2O-TiO2/sepiolite composite is also discussed.

Graphical AbstractUnder visible-light irradiation, the photo-generated electrons on the surface of Ag2O would transfer into the conduction band (CB) of TiO2 and then reacted with O2 molecules to generate •O2−. The organic dye was degraded by the photo-generated holes and •O2− active species.Figure optionsDownload full-size imageDownload as PowerPoint slide