A highly efficient visible-light-activated photocatalyst based on bismuth- and sulfur-codoped TiO2

Titanium dioxide (TiO(2)) codoped with bismuth (Bi) and sulfur (S) elements was prepared by a simple sol-gel method using tetrabutyl titanate, bismuth nitrate pentahydrate, and thiourea as precursors. The codoped TiO(2) calcined at 400 degrees C exhibits an intense absorption in the range of 500-800 nm. The absorption edge corresponds to a band gap of 2.0 eV. An indigo carmine solution of 20 mg/L was completely photodegraded in 40 min in the presence of such photocatalyst under visible light (lambda > 410 nm). This highly active photocatalytic performance is associated with the existence of numerous oxygen vacancies, the acidic sites on the surface of TiO(2), and the high specific surface area.