S-Scheme 2D/2D Heterojunction of ZnTiO3 Nanosheets/Bi2WO6 Nanosheets with Enhanced Photoelectrocatalytic Activity for Phenol Wastewater under Visible Light

Abstract

The pollution of phenol wastewater is becoming worse. In this paper, a 2D/2D nanosheet-like ZnTiO3/Bi2WO6 S-Scheme heterojunction was synthesized for the first time through a two-step calcination method and a hydrothermal method. In order to improve the separation efficiency of photogenerated carriers, the S-Scheme heterojunction charge-transfer path was designed and constructed, the photoelectrocatalytic effect of the applied electric field was utilized, and the photoelectric coupling catalytic degradation performance was greatly enhanced. When the applied voltage was +0.5 V, the ZnTiO3/Bi2WO6 molar ratio of 1.5:1 had highest degradation rate under visible light: the degradation rate was 93%, and the kinetic rate was 3.6 times higher than that of pure Bi2WO6. Moreover, the stability of the composite photoelectrocatalyst was excellent: the photoelectrocatalytic degradation rate of the photoelectrocatalyst remained above 90% after five cycles. In addition, through electrochemical analysis, XRD, XPS, TEM, radical trapping experiments, and valence band spectroscopy, we found that the S-scheme heterojunction was constructed between the two semiconductors, which effectively retained the redox ability of the two semiconductors. This provides new insights for the construction of a two-component direct S-scheme heterojunction as well as a feasible new solution for the treatment of phenol wastewater pollution.

Advances in the Application of Bi-Based Compounds in Photocatalytic Reduction of CO2

“…At the same time, surface atoms tend to escape from the lattice during the size reduction of nanomaterials, inducing the generation of surface defects. Jiang et al [ 58 ] prepared S-Scheme 2D/2D heterojunction ZnTiO 3 nanosheets/Bi 2 WO 6 nanosheets as catalysts. The catalyst structures are shown in Figure 5 .…”

“… ( a , b ) SEM imagesZnTiO 3 /Bi 2 WO 6 heterojunction sample, ( c ) TEM image and ( d ) HRTEM image of ZnTiO 3 /Bi 2 WO 6 heterojunction sample [ 58 ]. …”

Synthesis, Characterization of Dy2NdSbO7/Bi2WO6 Heterojunction Photocatalyst and the Application for the Photocatalytic Degradation of Chlorpyrifos under Visible Light Irradiation

“…Through this meticulous analysis, a total of nine distinct intermediate products were successfully identified and characterized. Therefore, the most plausible explanation is that DBHP operates through a direct type-S photocatalytic mechanism [131,132]. In the direct type-S heterojunction, the heterostructure formed between the two samples not only retains superior redox potentials but also reduces the recombination rate of PCC.…”