Bismuth oxyhalide quantum dots modified sodium titanate necklaces with exceptional population of oxygen vacancies and photocatalytic activity

Abstract

We here demonstrate the controlled synthesis of BiOBr quantum dots (QDs) decorated Na₂Ti₃O₇ necklaces via a hydrothermal transformation of sodium titanate nanotubes. The BiOBr QDs are deposited on the surface of Na₂Ti₃O₇ necklaces, forming a heterogeneous interface of BiOBr(200) and Na₂Ti₃O₇(110), which promotes the separation efficiency of photogenerated charges, thus resulting in its superior catalytic performance in the photo-oxidation of benzyl alcohol. The BiOBr/Na₂Ti₃O₇-1.0 exhibiting highest oxygen defect population gives best photocatalytic activity with a promising conversion rate of 3.32 mmol_{reacted BA} g_catal.^-1h^-1, which is substantially higher than the corresponding reported photocatalysts. DFT results corroborate the superior performance of BiOBr/Na₂Ti₃O₇ is mainly due to the formation of a built-in electric field and given efficiently the charge transfer between BiOBr(200) and Na₂Ti₃O₇(110). In all, this study reports a simple in-situ hydrothermal growth protocol to efficiently construct BiOBr/Na₂Ti₃O₇ heterojunction composites and offers guidelines for design of a new synthetic strategy to prepare efficient photocatalysts.

Keywords: BiOBr; Na(2)Ti(3)O(7); Oxygen vacancies; Photo-oxidation; Quantum dots.