One-step hydrothermal synthesis of MIL-88A/BiOCl0.1Br0.9(M88/BCB) solid solution Z-scheme heterojunction photocatalysts

Abstract

In this paper, M88/BCB Z-scheme heterojunction photocatalysts were synthesized by a one-step hydrothermal method. A series of characterization analyses showed that the introduction of iron-based MOF material M88 with mixed valence (Fe²⁺/Fe³⁺) increased not only the specific surface area of BCB, which was 2.2 times higher than that of BiOCl_0.1Br_0.9 solid solution, but also the existence of Fe²⁺/Fe³⁺ redox centers promoting the in situ photoFenton-like reaction, which could generate more ˙O₂⁻ and ˙OH. In addition, the introduction of M88 further enhances the visible light response capability of BCB and the separation efficiency of photogenerated carriers. Under visible light for 120 min, 10% M88/BCB can degrade 89.74% of TC, which is 2.1 times and 1.6 times higher than that of M88 and BCB, respectively. A possible photocatalytic degradation mechanism of Z-scheme heterojunctions was proposed based on the study of the band structure and the capture experiment of active species.