S-scheme heterojunction BP/WO3 with tight interface firstly prepared in magnetic stirring reactor for enhanced photocatalytic degradation of hazardous contaminants under visible light

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.

Anchoring black phosphorous quantum dots on Bi2WO6 porous hollow spheres: A novel 0D/3D S-scheme photocatalyst for efficient degradation of amoxicillin under visible light

Reasonable regulation of the micro-morphology of material can significantly enhance the related performance. Herein, bismuth tungstate (Bi₂WO₆, simplified as BWO) porous hollow spheres with flower-like surface were prepared successfully, and this unique morphology endowed BWO with improved photocatalytic performance by reflecting and absorbing the light multiple times inside the cavity. To inhibit the rapid recombination of photogenerated e^--h⁺ pairs within BWO itself, black phosphorous quantum dots (BPQDs) were anchored onto the nanosheets of BWO sphere closely by a facile self-assembly process, which will not shade the pores of BWO owing to the small size of BPQDs, but the BP nanosheets have the chance to do that. The band gap of BPQDs expanded much after exfoliation due to the quantum confinement effects, which matched the energy band of BWO well to form S-scheme heterojunction, achieving more efficient separation of photogenerated charges. As a result, the BPQDs/BWO exhibited attractive photocatalytic performance in the degradation of amoxicillin (AMX) and other antibiotics. Besides, the operation conditions were optimized, specifically, 94.5 % of AMX (20 mg/L, 200 mL) can be removed in 60 min when 50 mg of 2BPQDs/BWO was used as catalyst with solution pH = 11. Moreover, a possible degradation pathway of AMX was proposed based on the detected intermediates.

2D–2D WO3–Bi2WO6 photocatalyst with an S-scheme heterojunction for highly efficient Cr(vi) reduction

WO3–Bi2WO6 heterostructures display outstanding photo-reduction ability for high concentration of Cr(vi) due to the formation of 2D–2D junctions and the S-scheme transfer behavior of photogenerated e–h pairs.