Constructing S-scheme heterojunction of octahedral flower-like ZnIn2S4/Bi2WO6 nanocone with enhanced photocatalytic activity

Photocatalytic Enhancement and Recyclability in Visible-Light-Responsive 2D/2D g-C3N4/BiOI p-n Heterojunctions via a Z-Scheme Charge Transfer Mechanism

With the intensification of the energy crisis and the growing concern over environmental pollution, particularly the discharge of organic dye pollutants in industrial wastewater, photocatalytic degradation of these contaminants using solar energy has emerged as an effective, eco-friendly solution. In this study, we successfully synthesized 2D/2D g-C3N4/BiOI p-n heterojunctions via a simple precipitation method and a high-temperature calcination method. The unique 2D structures of g-C3N4 nanosheets (NSs) and BiOI NSs, coupled with the synergistic effect between the two materials, significantly enhanced the photocatalytic degradation performance of the heterojunctions under simulated sunlight. The band structures, as determined by Tauc curves, Mott-Schottky curves and XPS-VB analysis, revealed a Z-scheme charge transfer mechanism that efficiently reduced charge carrier recombination and improved electron-hole separation. The photocatalytic activity of 2D/2D g-C3N4/BiOI p-n heterojunctions for rhodamine B (Rh B) degradation reached 99.7% efficiency within 60 min, a 2.37-fold and 1.27-fold improvement over pristine BiOI NSs and g-C3N4 NSs, respectively. Furthermore, the heterojunction exhibited excellent recyclability stability, with the degradation efficiency decreasing by only 1.2% after five cycles. Radical scavenging experiments confirmed the involvement of superoxide radicals (∙O2-) and hydroxyl radicals (∙OH) as the primary reactive species in the degradation process. This work highlights the potential of 2D/2D g-C3N4/BiOI p-n heterojunctions for efficient photocatalytic applications in environmental remediation.

Construction of 2D S-Scheme Heterojunction Photocatalyst

Semiconductor photocatalytic technology holds immense promise for converting sustainable solar energy into chemically storable energy, with significant applications in the realms of energy and the environment. However, the inherent issue of rapid recombination of photogenerated electrons and holes hinders the performance of single photocatalysts. To overcome this challenge, the construction of 2D S-scheme heterojunction photocatalysts emerges as an effective strategy. The deliberate design of dimensionality ensures a substantial interfacial area; while, the S-scheme charge transfer mechanism facilitates efficient charge separation and maximizes redox capabilities. This review commences with a fresh perspective on the charge transfer mechanism in S-scheme heterojunctions, followed by a comprehensive exploration of preparation methods and characterization techniques. Subsequently, the recent advancements in 2D S-scheme heterojunction photocatalysts are summarized. Notably, the mechanism behind activity enhancement is elucidated. Finally, the prospects for the development of 2D S-scheme photocatalysts are presented.