Fractional Thermal Reduction of CuInS₂ Quantum Dot-Sensitized Bi₂MoO₆ Hierarchical Flowers on S-Doped Biochar for Dual Z-Scheme/Mott–Schottky Heterojunction Construction: A Strategy for Efficient Photocatalytic Biorefineries

Abstract

In this work, an S-doped biochar-supported CuInS 2 quantum dot-sensitized Bi 2 MoO 6 hierarchical flower ( [email protected] @SL) was prepared using a bottom-up technique. The partial thermal reduction of CuInS 2 quantum dot-sensitized Bi 2 MoO 6 successfully fabricated a dual heterojunction, which is composed of CuInS 2 /Bi 2 MoO 6 Z-scheme and Bi/Bi 2 MoO 6 Mott–Schottky heterojunctions. The dual heterojunction was identified by X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy. Under the synergistic effect of the dual heterojunction, the electronic kinetics was significantly improved. Furthermore, the charge transfer resistance was further reduced by S-doped biochar. Under visible light irradiation, an exceptional xylonic acid yield of 86.59% was realized by [email protected] @SL. In this photocatalytic system, all active oxidation species, namely, · OH, 1 O 2, · O 2 –, and h +, were beneficial for producing xylonic acid. The primary role of h + in the photocatalytic system was demonstrated via a poisoning experiment. According to XPS, the poisoning experiment, and electron spin resonance, the generation of · O 2 – reveals a Z-scheme heterojunction between CuInS 2 and Bi 2 MoO 6 .