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Nanocellulose has become an attractive biodegradable material for surface-enhanced Raman scattering (SERS) sensors. However, the development of nanofibrillar cellulose-based SERS substrates that are simultaneously flexible, highly sensitive, uniform, and stable remains a great challenge. Herein, a highly sensitive, reliable, and flexible gold nanoparticle-decorated bacterial nanocellulose (AuNPs@BNC) SERS substrate with three-dimensional (3D) high-density hot spots was constructed by the combination of in situ chemical reduction and vacuum filtration. The homogeneous AuNPs were grown in situ on the surface of networked bacterial cellulose nanofibers to form 3D high-density SERS hotspots. In addition, the hydrophilic BNC with good adsorption and permeability properties could capture target molecules in the high-density hotspot region to further enhance the SERS performance. As a result, the 3D AuNPs@BNC SERS substrate not only demonstrates a high detection sensitivity of up to 1.0 × 10–10 M and an enhancement factor of 1.8 × 107 for methylene blue molecules but also shows excellent signal reproducibility (relative standard deviation (RSD) = 8.3%) and long-term storage stability (over two months). Furthermore, the flexible 3D AuNPs@BNC SERS substrate is also able to detect trace malachite green (MG) with a low detection limit of 1.0 × 10–11 M and prominent signal homogeneity of RSD = 7.8%. Besides, hazardous MG residues on the surface of shrimp could be directly identified by using flexible AuNPs@BNC SERS substrates through a feasible wipe-and-peel method. The flexible, reliable, and stable AuNPs@BNC substrate is promising for direct, sensitive, and rapid on-site detection of toxic molecules on seafood. [ABSTRACT FROM AUTHOR]

In this study, a visible-light-driven photocatalyst BiWO was assembled on fibers by linking of poly(diallyldimethylammonium chloride) (PDDA) at room temperature. The samples were characterized by scanning electron microscopy, energy-dispersive spectroscopy and X-ray diffraction. Photocatalytic activity was evaluated by degradation of Rhodamine B (RhB) and Acid orange 7 (AO7) under visible light irradiation. Effects of concentration of PDDA in the pretreatment solution on degradation efficiency of RhB and AO7 in the presence of BiWO coated cotton fabrics were investigated. In addition, washing durability and breaking strength of BiWO coated cotton fabrics modified with PDDA were examined. The results revealed that BiWO with irregular shape were successfully coated on the cotton fabric modified with PDDA. BiWO coated cotton fabric modified with PDDA exhibited excellent photocatalytic activity with degradation efficiency of 97.4% of RhB and 94.5% of AO7, respectively. In addition, BiWO coating on the cotton fabrics modified with PDDA not only improved washing durability but also enhanced breaking strength of the fabric. [ABSTRACT FROM AUTHOR]

The environmental repercussions of wastewater from the dye process mean that it is very important to obtain an eco-friendly photocatalyst that would degrade wastewater. Herein, bismuth tungstate/graphene oxide (Bi2WO6/GO) composites are fabricated through in-situ hydrothermal reaction and then the Bi2WO6/GO photocatalysts are deposited onto polyethylene terephthalate (PET) fabric. The obtained Bi2WO6/GO deposited PET fabrics are then characterized through XPS, Raman, SEM, TEM, XRD, UV-vis, BET method and photoluminescence spectroscopy (PL) to investigate their chemical and crystal structures, morphology, optical property, surface area and photochemical properties. Photocatalytic performance is studied through examining the rate of degrading rhodamine B (RhB) under visible light. Surface of PET fibers is densely covered with Bi2WO6/GO. Bi2WO6/GO deposited PET fabrics show a broad absorption band in the visible spectra. Removal rate of RhB on the Bi2WO6/GO deposited PET fabric is the highest with the GO content of 2 g/L (labeled as Bi2WO6/2 g/LGO). The result of active species experiment shows that superoxide radicals (·O2−) plays a major role in the degradation of RhB. Moreover, Bi2WO6/2 g/LGO deposited PET fabric shows excellent cycle stability of photocatalytic degradation for RhB. The findings in this work can be extended to preparation other types of composite on the textile for photocatalysis, which can be applied to remove dyes in the wastewater produced by the textile or leather industry. [ABSTRACT FROM AUTHOR]

The polarization-induced internal electric field (IEF) in ferroelectric materials could promote photogenerated charge transfer across the heterojunction interface, but the effect of polarization-induced IEF on the mechanism of photogenerated charge transfer is ambiguous. In this study, a KNbO 3 -CuO heterojunction was synthesized by depositing copper oxide (CuO) onto KNbO 3 . Incorporating CuO broadens the light absorption of KNbO 3 , thereby enhancing the dissociation of the photogenerated charges. The results show that the polarization-induced IEF in KNbO 3 determines that the charge transport mechanism in the KNbO 3 -CuO heterojunction follows the S-scheme. Owing to the S-scheme heterojunctions and efficient CO 2 capture and activation by CuO, the CH 4 production rate of KNbO 3 -CuO increased by nearly 26 times compared to KNbO 3 . Additionally, the CH 4 selectivity of KNbO 3 -CuO could reach up to 97.80%. This research offers valuable insights into enhancing the photogenerated charge separation and constructing heterojunctions.