Visible light active Ag@SrTiO3: a powerful photocatalyst for NOx degradation

Exploiting visible light for NOx degradation represents an important challenge to enhance the air quality of our environment. In the present study, the photocatalytic activities of two commercial strontium titanate (STO) having different sizes (micro and nano) were compared towards NOx degradation under LED light. The decoration of both STO photocatalysts by Ag nanoparticles (8 theoretical wt.%) led to enhanced photocatalytic efficiency more than twice. In particular, nano-sized Ag@STO showed the highest activity (75% of NOx degradation) within 180 min due to Ag nanoparticles (NPs) localized surface plasmon resonance (LSPR) properties and the large surface area of nano-STO. The photocatalysts were synthesized by the wet impregnation method and calcined at 400 °C. Their structural, morphological, specific surface area, and optical properties were characterized by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), N2 adsorption/desorption analysis, and UV–Vis diffuse reflectance spectroscopy (DRS).