Boron-doped rutile TiO2/ anatase TiO2/ ZrTiO4 ternary heterojunction photocatalyst with optimized phase interface and band structure

Abstract

To improve the photocatalytic performance of TiO2-based heterostructures, Z-scheme/Ⅱ-type rutile TiO2 (R)/anatase TiO2 (A)/ZrTiO4 ternary heterojunction photocatalyst was designed and prepared via a facile one-step calcining strategy. Phase interface and band structure of the materials were controlled and optimized by regulating R–TiO2/A–TiO2 mass ratio in the TiO2 (A, R)/ZrTiO4 structures using boron doping. The highest photocatalytic performance and excellent catalytic stability of Rhodamine B removal was observed from the heterojunction with a low R–TiO2/A–TiO2 mass ratio of 0.066, even after five testing cycles, accompanying with low photoluminescence intensity and electrochemical impedance, high photocurrent and charge carrier density (5.12 × 1022 cm−3), and a positive shift of valence band position (from +2.06 to + 2.16 eV). The increased photodegradation behaviour was due to the remarkably enhanced separation efficiency and improved redox ability of the photo-induced charge carriers as a result of the high content of oxygen vacancies and the formed anatase TiO2/rutile TiO2 Z-scheme heterojunction.