Ultrasonic spray pyrolysis synthesis and visible light activity of carbon-doped Ti0.91Zr0.09O2 solid solution photocatalysts

Visible light active carbon-doped Ti0.91Zr0.09O2 solid solution photocatalysts were directly obtained by ultrasonic spray pyrolysis of an aqueous solution containing TiCl4, ZrOCl2·8H2O and CH3(CH2)17NH2. The samples were characterized by X-ray diffraction, scanning electron microscopy, nitrogen adsorption, X-ray photoelectron spectroscopy, UV–vis diffuse reflectance spectroscopy and infrared spectroscopy. The characterizations revealed the spherical structures of the resulting samples and the substitution of Ti4+ by Zr4+ ions and carbon in the TiO2 lattice. Meanwhile, partial carbon and zirconium existed in the form of carbonate and zirconia, respectively. Moreover, the pyrolysis temperature had significant effect on the amount of dopants substituted in the resulting samples. The carbon doping successfully extended the absorption edges of the solid solution to visible light region. We evaluated photocatalytic activities of the doped solid solution photocatalysts on degradation of rhodamine B in aqueous solutions under visible light irradiation (λ ≥ 420 nm). It was found that the carbon-doped solid solution photocatalysts exhibited enhanced photocatalytic activity under visible light irradiation comparing to the undoped counterpart. On the basis of characterization results, we attributed the enhanced visible light activity to the carbonate species in solid solution photocatalysts. This study provides a way to synthesize visible light active solid solution photocatalysts on a large scale.