CFs/g-C3N4/BiOBr bundles have been prepared, and they can be woven into recyclable cloth-shaped visible-light-driven photocatalyst for degrading TC-HCl in water.
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•In-situ growth of ...g-C3N4/BiOBr heterojunctions on CFs.•Broad photoabsorption and high photocurrent of CFs/g-C3N4/BiOBr.•Simple weave of CFs/g-C3N4/BiOBr fibers to cloth.•High photocatalytic activity and simple recyclable process.
The photocatalytic degradation of tetracycline (TC) in water has received much attention, but its practical application in the river has been limited by a lack of efficient and recyclable visible-light-driven photocatalysts. To solve this problem, with flexible carbon fiber (CF) bundles as substrate, we have reported the in-situ growth of g-C3N4/BiOBr heterojunctions as weaveable photocatalyst. g-C3N4 nanosheets (thickness: ~30 nm, diameter: 0.4–1 μm) and BiOBr layer (thickness: ~25 nm, diameter: 200–500 nm) were grown on CFs successively. CFs/g-C3N4/BiOBr bundles could be woven into cloth (area: 5 × 5 cm2, weight: 0.15 g), and the cloth exhibited remarkably enhanced photodegradation efficiency (86.1%) for degrading TC-HCl in 120 min. In addition, h+, O2− and OH were demonstrated as the reactive species contributing to the elimination of TC-HCl. Especially, two possible pathways of degrading TC-HCl were proposed based on the intermediate products. Thus, CFs/g-C3N4/BiOBr could serve as a flexible, weaveable and recyclable photocatalyst for antibiotic elimination in an aqueous environment.
Semiconductor-mediated photocatalysis has received tremendous attention as it holds great promise to address the worldwide energy and environmental issues. To overcome the serious drawbacks of fast ...charge recombination and the limited visible-light absorption of semiconductor photocatalysts, many strategies have been developed in the past few decades and the most widely used one is to develop photocatalytic heterojunctions. This review attempts to summarize the recent progress in the rational design and fabrication of heterojunction photocatalysts, such as the semiconductor-semiconductor heterojunction, the semiconductor-metal heterojunction, the semiconductor-carbon heterojunction and the multicomponent heterojunction. The photocatalytic properties of the four junction systems are also discussed in relation to the environmental and energy applications, such as degradation of pollutants, hydrogen generation and photocatalytic disinfection. This tutorial review ends with a summary and some perspectives on the challenges and new directions in this exciting and still emerging area of research.
The design, construction, and photocatalytic performances of semiconductor heterojunction photocatalysts are briefly reviewed and selectively highlighted.
The shape‐controlled synthesis of nano‐ and microstructured materials has opened up new possibilities to improve their physical and chemical properties. In this work, new types of Bi2WO6 with complex ...morphologies, namely, flowerlike, tyre‐ and helixlike, and platelike shapes, have been controllably synthesized by a facile hydrothermal process. The benefits of the present work also stem from the first report on the transformation of Bi2WO6 from three‐dimensional (3D) flowerlike superstructures to 2D platelike structures, and on the formation of tyre‐ and helixlike Bi2WO6 superstructures. UV/Vis absorption spectra show that the optical properties of Bi2WO6 samples are relevant to their size and shape. More importantly, the photocatalytic activities of Bi2WO6 nano‐ and microstructures are strongly dependent on their shape, size, and structure for the degradation of Rhodamine B (RhB) under visible‐light irradiation. The reasons for the differences in the photocatalytic activities of these Bi2WO6 nano‐ and microstructures are further investigated.
Shaping up: Bi2WO6 samples with complex morphologies of flower‐ (A), tyre‐ (B), helix‐ (C), and platelike (D) shapes (see image), are controllably synthesized by a facile hydrothermal process. All of the synthesized Bi2WO6 nano‐ and microstructures exhibit interesting shape‐associated optical properties and visible‐light‐driven photocatalytic activity.
Interfacial adhesion in fiber reinforced composites is a critical factor for their mechanical performance in structural applications. As nanomaterials continue to rise in prominence, the use of ...nanostructured interphases has grown to become a viable technique to reinforce the fiber-matrix interface of fiber reinforced polymer composites. Here, a polymeric interphase consisting of aramid nanofibers (ANFs) is introduced on Poly(diallyldimethylammonium chloride) (PDDA) coated fiberglass through electrostatic adsorption. The simple and rapid coating technique considerably roughens the inorganic fiber surface, while enriching it with polar functional groups that are capable of chemically bonding with the matrix, all while preserving the structural integrity of the fiber. The nanostructured coating improves the interfacial shear strength by up to 83.2%, along with a 35.3% improvement in short beam shear strength. These improvements can be attributed to the enhanced chemical and mechanical interactions between the fiber and the matrix. The following findings highlight the potential for the utilization of a PDDA coating to enhance the adhesion of ANFs on fiberglass and enable the fabrication of composite structures with higher strength and toughness through a rapid, simple and effective surface treatment.
Fiber‐based flexible thermoelectric energy generators are 3D deformable, lightweight, and desirable for applications in large‐area waste heat recovery, and as energy suppliers for wearable or mobile ...electronic systems in which large mechanical deformations, high energy conversion efficiency, and electrical stability are greatly demanded. These devices can be manufactured at low or room temperature under ambient conditions by established industrial processes, offering cost‐effective and reliable products in mass quantity. This article presents a critical overview and review of state‐of‐the‐art fiber‐based thermoelectric generators, covering their operational principle, materials, device structures, fabrication methods, characterization, and potential applications. Scientific and practical challenges along with critical issues and opportunities are also discussed.
Fiber‐based thermoelectric generators (FTEGs) are 3D deformable, lightweight, and desirable for applications and can be manufactured at low or room temperature under ambient conditions. This article presents a critical overview and review of state‐of‐the‐art FTEGs, covering their operational principle, materials, device structures, fabrication methods, characterization, and potential applications. Scientific and practical challenges along with critical issues and opportunities are discussed.
Spatial control over the wetting properties of graphene surfaces is a desired feature in numerous applications. Traditionally, this is achieved using time consuming chemical treatment processes that ...lack spatial tuning. Here, we demonstrate the use of laser induced graphene for the direct, spatial printing of surfaces with either superhydrophilic or superhydrophobic character through simple and convenient control over graphene array morphology, and without the need for chemical surface modification. The wetting properties of the graphene surfaces range from superhydrophilic (0°) for sheet-like structures, to superhydrophobic (>150°) for micro-pillar and hemispherical structures. By varying the induction parameters of the CO2 laser, we demonstrate the ability to write patterns with spatially tailored wettability to enable liquid micro-patterning and channeling of flow. Furthermore, we study solid-liquid interactions for such surfaces using viscosity measurements, where a “petal effect” is observed in the graphene material, thus revealing the parahydrophobicity of the surface.
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Bacterial inactivation by magnetic photocatalyst receives increasing interests for the ease recovery and reuse of photocatalysts. This study investigated bacterial inactivation by a magnetic ...photocatalysts, Fe2O3–AgBr, under the irradiation of a commercially available light emitting diode lamp. The effects of different factors on the inactivation of Escherichia coli were also evaluated, in term of the efficiency in inactivation. The results showed that Fe2O3–AgBr was able to inactivate both Gram negative (E. coli) and Gram positive (Staphylococcus aureus) bacteria. Bacterial inactivation by Fe2O3–AgBr was more favorable under high temperature and alkaline pH. Presence of Ca2+ promoted the bacterial inactivation while the presence of SO42− was inhibitory. The mechanisms of photocatalytic bacterial inactivation were systemically studied and the effects of the presence of various specific reactive species scavengers and argon suggest that Fe2O3–AgBr inactivate bacterial cells by the oxidation of H2O2 generated from the photo-generated electron and direct oxidation of photo-generated hole. The detection of different reactive species further supported the proposed mechanisms. The results provide information for the evaluation of bacterial inactivation performance of Fe2O3–AgBr under different conditions. More importantly, bacterial inactivation for five consecutive cycles demonstrated Fe2O3–AgBr exhibited highly stable bactericidal activity and suggest that the magnetic Fe2O3–AgBr has great potential for water disinfection.
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•The bactericidal ability of magnetic Fe2O3–AgBr under LED lamp was demonstrated.•The effects of various factors on bacterial inactivation by Fe2O3–AgBr were studied.•Fe2O3–AgBr stably inactivated 7-log of Escherichia coli in five repeated cycles.•Fe2O3–AgBr inactivated bacteria by oxidation of H2O2 and direct oxidation of h+.
BiOBr-based nanocomposite photocatalysts are used for removing the organic pollutants, but their poor adsorption/photocatalytic performances and the low potential for recycling limit their ...application. To solve the issue, herein we report a large-area recyclable CFC/BiOBr/ZIF-67 filter-membrane-shaped photocatalyst prepared by
in situ
growth of BiOBr/ZIF-67 nanocomposites on carbon fiber cloth (CFC). Fabrication process is based on hydrothermal synthesis of BiOBr nanosheets (diameter 0.5–1 μm) on carbon fiber cloth (as substrate material) and then a chemical bath route is used to grow ZIF-67 nanoparticles (diameter 300–600 nm)
in situ
on the surface of CFC/BiOBr. Resulted composite, CFC/BiOBr/ZIF-67, exhibits a high specific surface area (545.82 m
2
g
−1
) and a wide photoabsorption, accompanied by an absorption edge (~ 620 nm). In dark condition, CFC/BiOBr/ZIF-67 adsorbs bisphenol A (BPA) and orange 7 (AO7) within 60 min, respectively with 20.0% and 40.1% efficiency. This level of efficiencies are correspondingly 2.6 and 3.2 times more that of the bare CFC/BiOBr (7.6% for BPA and 12.4% for AO7). Under visible light irradiation, CFC/BiOBr/ZIF-67 can degrade 69.7% of BPA and 96.0% of AO7, in 120 min, which are, respectively, 1.3 and 1.8 times higher than the absorption efficiency of bare CFC/BiOBr (53.2% for BPA, 52.0% for AO7). When CFC/BiOBr/ZIF-67 is used as a filter membrane for photocatalytic removal of pollutants in flowing wastewater (AO7, rate: ~ 1.5 L h
−1
), 92.2% of AO7 can be decomposed after 10 filtering cycles. This study suggests CFC/BiOBr/ZIF-67 as a novel highly functional, recyclable and environmental friendly photo-driven membrane filter for purification and recovery of flowing surface waste waters.
Graphical abstract
Hydrogen concentrations in minerals of peridotite xenoliths in alkali basaltic rocks from Quaternary volcanoes in northwest Spitsbergen were measured using polarized Fourier transform infrared ...spectroscopy (FTIR) to trace the effects of geologic processes on hydrogen distribution in the continental lithospheric mantle. The mineral grains show hydrogen profiles with lower concentrations at rims suggesting diffusive hydrogen loss during the entrapment and transport of the xenoliths in magma. However, hydrogen concentrations in the centers of the grains are uniform and appear to represent hydrogen abundances in the Spitsbergen upper mantle. The olivine, orthopyroxene, and clinopyroxene contain 1-10, 130-290, and 350-560 ppm H2O, respectively. Hydrogen abundances away from metasomatic melt conduits recorded by Type 1 xenoliths are correlated with the concentrations of incompatible trace elements, indicating that hydrogen distribution is related to mantle metasomatism. By contrast, hydrogen near the melt conduits, recorded by Type 2 xenoliths, shows no regular correlations with incompatible trace elements (except Nb in clinopyroxene) and may be affected by fractional crystallization of amphibole in the conduits. Hydrogen contents decrease away from the melt conduits and are controlled by the interaction between the depleted host mantle and percolating metasomatic melts. Therefore, the metasomatic melt could have variably hydrated the Spitsbergen upper mantle via different processes. The H2O/Ce ratios of the melt in equilibrium with clinopyroxene near the metasomatic melt conduits range from 93 to 218, i.e., within the oceanic island basalt (OIB) range. This is consistent with that the metasomatic melt could have been derived from OIB-type sources evidenced by the Sr-Nd isotope compositions of the xenoliths.
A new photothermal coupling agent for photothermal ablation (PTA) therapy of tumors is developed based on ultrathin PEGylated W18O49 nanowires. After being injected with the nanowire solution, the in ...vivo tumors exhibit a rapid temperature rise to 50.0 ± 0.5 °C upon irradiation with NIR laser light at a safe, low intensity (0.72 W cm−2) for 2 min (left‐hand mouse in the figure),), resulting in the efficient PTA of cancer cells in vivo in 10 min.
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