Tightly and abundantly contacted Z-scheme heterojunction of Bi-modified TiO2/BiOCl: In-situ construction and boosting visible-light-driven purification of liquor brewing wastewater

Abstract

The lower specific surface area and limited surface contact between BiOCl and TiO2 in composite fabricated by hybridization of TiO2 with BiOCl extremely hinder its catalytic performance. In this work, the area of interface contact between BiOCl and TiO2 was increased through the mediation of SiO2, and a Bi-modified ternary 0D/2D/2D TiO2/BiOCl Z-scheme heterojunction photocatalyst with large specific surface area (= 237.83 m2g−1) and surface plasmon resonance (SPR) effect was constructed in situ by ingeniously utilizing the reduction of carbon species generated during the calcination process. The results show that the COD removal rate of Bi/TBOC-10% for real liquor brewing wastewater (LBW) reaches 90.5% after 10 hours of visible light irradiation, which is 2.6 times and 2.1 times that of TiO2 and Degussa P25, respectively. The COD removal rate of the composite was reduced only by 8.9% after five cycles of performance test (50 h). Photoluminescence spectroscopy (PL), Transient Photocurrent Response (TPR), Electrochemical Impedance Spectroscopy (EIS) and BET characterization suggest that its excellent photocatalytic activity should be attributed to the Z-scheme heterojunction that broadens the light absorption range while retains strong oxidation-reduction active sites, the SPR effect that facilitates the separation and migration of photogenerated carriers, and high specific surface area of the composite that provides more active sites for the photodegradation reaction.