Photocatalytic properties of flower-like BiOBr/BiOCl heterojunctions in-situ constructed by a reactable ionic liquid

Insight into the improved photocatalytic removal of tetracycline hydrochloride by constructing cobalt doping in 2D/2D (BiO)2CO3/BiOCl type-II heterojunctions

Element doping coupled with heterojunction construction and morphology control is an efficient way to improve the properties of photocatalytic materials. Here, a thiourea-modified 2D/2D cobalt-doped (BiO)₂CO₃/BiOCl heterojunction photocatalyst (denoted as Co-(BC/BL)_Tu) was constructed by a simple one-pot hydrothermal method. The photocatalytic property of Co-(BC/BL)_Tu product was evaluated by the photocatalytic degradation of tetracycline hydrochloride (TC-HCl). Compared with the pure (BiO)₂CO₃ sample, the as-prepared Co-(BC/BL)_Tu product displayed outstanding visible-light-driven photodegradation property. The photodegradation rate constant k value of the Co-(BC/BL)_Tu product was 5.2 times higher than that of pure (BiO)₂CO₃, which was the result of the synergistic effect of the 2D/2D structure, cobalt doping and type-Ⅱ heterostructures. It could simultaneously boost the visible light harvesting of the photocatalytic system as well as charge separation. This study provides a facile and promising strategy for constructing a high-effective photocatalytic system by combining morphology control engineering, doping engineering, and heterostructure engineering.

Construction of 3D sheet-packed hierarchical MoS2/BiOBr heterostructures with remarkably enhanced photocatalytic performance for tetracycline and levofloxacin degradation

In this paper, MoS₂ nanosheets were prepared and deposited on BiOBr microflowers through deposition-hydrothermal strategy. MoS₂ exhibited a string of nanosheets with wrinkled layer outlook, and MoS₂/BiOBr composites displayed a micro-flower morphology with the diameter of 2-3 μm. Visible-light harvesting performance was significantly improved in the region of 400-600 nm for MoS₂/BiOBr. The obtained MoS₂/BiOBr samples exhibited tremendous enhanced catalytic activity, which could degrade 92.96% of tetracycline and 90.31% of levofloxacin within 70 min. The photo-generated holes and ⋅OH radicals played the dominant roles in the whole photocatalytic decomposition process. Based on the analysis of DRS, BET, PL, and electrochemical results, the remarkably improved photocatalytic performance may be ascribed to the synergistic effect of strong visible-light harvesting ability, enhanced BET surface area, and faster separation or transfer efficiency of photo-generated charges.

Panax notoginseng powder -assisted preparation of carbon-quantum-dots/BiOCl with enriched oxygen vacancies and boosted photocatalytic performance

Low activity of photocatalysts is a serious bottleneck to the practical application of photocatalytic technology. In this paper, a series of BiOCl composite photocatalysts containing carbon quantum dots (CQDs) were successfully prepared by adding Panax notoginseng powder (PNP) to the solvothermal synthesis system of BiOCl as a template agent and a raw material for 0D CQDs. CQDs/BiOCl exhibit 2D flake structures and 3D flower-like microspheres self-assembled from thin flakes, holding rich oxygen vacancies (OVs). After detailed characterization, it was found that the amount of OVs on BiOCl could be regulated according to the amount of PNP added. The CQDs/OVs-BiOCl photocatalysts exhibit higher photogenerated charge separation efficiency and photocatalytic activity than the bare BiOCl. When the mass ratio of PNP/BiOCl is 1.0%, the photocatalyst demonstrates the maximum degradation activity for rhodamine B (RhB) and perfluorooctanoic acid (PFOA). In view of the solid observations, a photocatalytic enhancement mechanism of CQDs/BiOCl was elucidated.