Bi-Enhanced Bi_xTi_(4-x)O₇ Heterojunctions for Improved Photocatalytic Activity in Tetracycline Removal

The photocatalytic proficiency of Bi₂Ti₂O₇ is hindered by its inadequate solar energy harnessing capability and swift electron-hole recombination dynamics. In the investigation, the study innovated Bi metal oxide heterostructures by embedding Bi nanoparticle-modified Bi_xTi_(4-x)O₇ composites, systematically synthesizing a suite of Bi/BT materials through meticulous tuning of the Bi and Ti precursor ratios. Notably, the Bi/BT-2 series was examined for its photocatalytic performance in tetracycline (TC) degradation. The findings revealed that Bi/BT-2 exhibited remarkable TC degradation efficiency, achieving a removal rate of 99.6 %, which surpasses BT-2 by a factor of 3.25 and TiO₂ by 1.67 times. Mechanistic probing unveiled that the incorporation of nanostructured Bi onto the Bi_xTi_(4-x)O₇ surface introduced fresh active sites, dramatically bolstering the photocatalytic activity by augmenting the light absorption spectrum and refining charge separation processes. Moreover, an exhaustive examination of the TC degradation mechanism facilitated by Bi/BT-2 demonstrated sustained efficiency exceeding 80 % across a pH range spanning from 3 to 9, emphasizing its promising potential for practical applications. This study contributes invaluable perspectives for the design of cutting-edge metal-oxide photocatalysts tailored for environmental remediation purposes. Synopsis: The low degradation efficiency of tetracycline has posed a major challenge in bismuth titanate research. To address this, a novel approach was implemented by developing a Bi_xTi_(4-x)O₇ composite catalyst modified with Bi nanoparticles. This modification forms a metal-oxide heterojunction, which significantly enhances the degradation efficiency.