(Sr0.6Bi0.305)2Bi2O7 as a new visible-light-responsive photocatalyst: An experimental and theoretical study

Abstract The pyrochlore-type (Sr0.6Bi0.305)2Bi2O7 containing Bi3+ and Bi5+ mixed valent states was first investigated as a new photocatalytic material in this work and successfully synthesized by a facile hydrothermal method. The phase structure, morphology, microstructure, elemental composition, and optical properties of samples were characterized in details. The experimental measurements combining with the first-principles calculations show that (Sr0.6Bi0.305)2Bi2O7 is a n-type semiconductor with a band gap of 1.25 eV. The photocatalytic activity of (Sr0.6Bi0.305)2Bi2O7 was evaluated by the degradation of various organic dyes. Our results show that (Sr0.6Bi0.305)2Bi2O7 exhibits high photocatalytic efficiency and stability under visible light irradiation. The calculated electronic density of states indicates that Bi and O atoms close to the Sr vacancy probably possess higher activity and are helpful for its photocatalytic performance.