Charge-compensated (Nb, Fe)-codoped La2Ti2O7 photocatalyst for photocatalytic H-2 production and optical absorption

摘要

The effects of dopant concentration on photocatalytic and optical absorption properties of (Nb, Fe) monodoped and codoped La2Ti2O7 (LTO) photocatalysts are investigated in this work. The phase structure, crystallinity and morphology are characterized to reveal that the dopant concentration is of great influence on the physical and chemical properties. Charge balance is kept in LTO by codoping of Nb5+ and Fe3+. First principle calculations prove that codoping with Nb and Fe could obviously narrow the band gap and enhance the photo-response in visible light region. When the (Nb, Fe) codoped concentration increases up to 0.01, the photocatalytic H-2 production rate reaches 3.68 times higher than that of pristine LTO, suggesting that synergistic effect of codoping is beneficial to improve photocatalytic efficiency. A reduction in photoluminescence and a great enhancement in photocurrents are observed for 1 wt% Pt loaded (Nb, Fe)-codoped LTO, indicating that the optimal codoping is of great importance in enhancing the optical absorption property, reducing the recombination of photogenerated carriers, and improving the photocatalytic activity. (C) 2017 Elsevier B.V. All rights reserved.