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Nano-carbon-reinforced polymer composites have gained much consideration in functional applications due to their attractive mechanical strength and cost-effectiveness. The surface chemistry and associated mechanical strength of carbon nanotubes (CNTs), graphene, and other carbon derivative-based nanocomposites are well understood. While CQDs are considered emerging carbon derivatives, their surface chemistry, unique physio-chemical properties, and dispersion behavior in polymers are yet to be explored. Therefore, in this work, CQDs with different structures were synthesized from lemon pulp and urea, and their rheology and mechanical strength were studied in the PVA matrix. The surface chemistry and structure of CQDs were controlled using different solvents and reaction temperatures, respectively. CQDs possessed a circular shape, with a size of <10 nm, having a suitable carbon core and functional groups, as confirmed by TEM and FTIR spectroscopy. The dynamic viscosity and particle size of PVA/CQDs films peaked at 4% inclusion due to the maximum crosslinking of U-CQDs with reinforcement at 180 °C. Compared with pure PVA, the optimized composite showed an 80% larger particle size with 67% better tensile strength at 4% U-CQDs concentration. In addition to enhanced mechanical strength, CQDs exhibited antibacterial activity in composites. These CQDs-reinforced PVA composites may be suitable for different functional textile applications (shape memory composites and photo-active textiles)., Competing Interests: All authors certify that they have NO affiliations with or involvement in any organization or entity with any financial interest (such as honoraria; educational grants; participation in speakers' bureaus; membership, employment, consultancies, stock ownership, or other equity interest; and expert testimony or patent-licensing arrangements), or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript., (This journal is © The Royal Society of Chemistry.)

Design of economical, large-scale, stable, and highly active bifunctional electrocatalysts for Zn-air batteries with enhanced oxygen reduction and oxygen evolution performance is needed. Herein, a series of electrocatalysts were facilely fabricated where in situ formed bimetallic nanoparticles aided in the growth of carbon nanotubes over carbon nanofibers (MM'-CNT@CNF) during thermal treatment. Different combinations of Fe, Ni, Co and Mn metals and melamine as precursor for CNT growth were investigated. The synergistic interaction between bimetallic nanoparticles and N-doped carbon results in greatly improved bifunctional catalytic activity for both oxygen reduction and evolution reactions (ORR, OER) using FeNi-CNT@CNF as catalyst. The half-wave potential (0.80 V vs. RHE) for FeNi-CNT@CNF for ORR was close to that of Pt/C (0.79 V vs. RHE), meanwhile its stability was superior to Pt/C. Likewise, during OER, the FeNi-CNT@CNF reached a current density of 10 mA cm -2 at a rather low overpotential of 310 mV vs. RHE compared to benchmark RuO 2 (410 mV). The rechargeable Zn-air prototype battery using FeNi-CNT@CNF as an air electrode outperformed the mixture of Pt/C and RuO 2 with discharge/charge overpotential of 0.61 V, power density of 118 mW cm -2 at 10 mA cm -2 and an improved cycling stability over 108 hours., Competing Interests: There are no conflicts of interest to declare., (This journal is © The Royal Society of Chemistry.)

Nanoscale surface roughness has conventionally been induced by using complicated approaches; however, the homogeneity of superhydrophobic surface and hazardous pollutants continue to have existing challenges that require a solution. As a prospective solution, a novel bubbled-structured silica nanoparticle (SiO 2 ) decorated electrospun polyurethane (PU) nanofibrous membrane (SiO 2 @PU-NFs) was prepared through a synchronized electrospinning and electrospraying process. The SiO 2 @PU-NFs nanofibrous membrane exhibited a nanoscale hierarchical surface roughness, attributed to excellent superhydrophobicity. The SiO 2 @PU-NFs membrane had an optimized fiber diameter of 394 ± 105 nm and was fabricated with a 25 kV applied voltage, 18% PU concentration, 20 cm spinning distance, and 6% SiO 2 nanoparticles. The resulting membrane exhibited a water contact angle of 155.23°. Moreover, the developed membrane attributed excellent mechanical properties (14.22 MPa tensile modulus, 134.5% elongation, and 57.12 kPa hydrostatic pressure). The composite nanofibrous membrane also offered good breathability characteristics (with an air permeability of 70.63 mm/s and a water vapor permeability of 4167 g/m 2 /day). In addition, the proposed composite nanofibrous membrane showed a significant water/oil separation efficiency of 99.98, 99.97, and 99.98% against the water/xylene, water/n-hexane, and water/toluene mixers. When exposed to severe mechanical stresses and chemicals, the composite nanofibrous membrane sustained its superhydrophobic quality (WCA greater than 155.23°) up to 50 abrasion, bending, and stretching cycles. Consequently, this composite structure could be a good alternative for various functional applications.

The water pollution becomes a serious concern for the sustainability of ecosystems due to the existence of pharmaceutical products (ceftriaxone (CEF) antibiotic). Even in low concentration of CEF has lethal effects on ecosystem and human health. To remove CEF, TiO 2 is considered as an effective and efficient nanoparticles, however its performance is reduced due to wider energy gap and rapid recombination of charge carriers. In this study, activated carbon based TiO 2 (ACT-X) heterogeneous nanocomposites were synthesized to improve the intrinsic properties of TiO 2 and their adsorption-photocatalytic performance for the removal of CEF. The characterization results revealed that ACT-X composites have slower recombination of charge carriers, lower energy band gap (3.05 eV), and better light absorption under visible region of light. From ACT-X composites, the ACT-4 photocatalyst has achieved highest photocatalytic degradation (99.6%) and COD removal up (99.2%). The results of radical scavengers showed that photocatalytic degradation of CEF is mainly occurred due to superoxide and hydroxyl radicals. Meanwhile, the reusability of ACT-4 up to five cycles shows more than 80% photocatalytic degradation, which make the process more economical. The highest experimental adsorption capacity is achieved up to 844.8 mg g -1 using ACT-4. The favorable and multilayer heterogeneous adsorption is carried out according to the well-fitted data with pseudo-second-order and Freundlich models, respectively. These results indicate that the carbon-based TiO 2 composites can be used as a green, stable, efficient, effective, reusable, renewable, and sustainable photocatalyst to eliminate the pharmaceutical pollutants (antibiotics) via adsorption and photocatalytic degradation processes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Nanofiber-based facial masks have attracted the attention of modern cosmetic applications due to their controlled drug release, biocompatibility, and better efficiency. In this work, Azadirachta indica extract (AI) incorporated electrospun polyvinyl alcohol (PVA) nanofiber membrane was prepared to obtain a sustainable and hydrophilic facial mask. The electrospun AI incorporated PVA nanofiber membranes were characterized by scanning electron microscope, Ultraviolet-visible spectroscopy (UV-Vis) drug release, water absorption analysis, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging, and antibacterial activity (qualitative and quantitative) at different PVA and AI concentrations. The optimized nanofiber of 376 ± 75 nm diameter was obtained at 8 wt/wt% PVA concentration and 100% AI extract. The AI nanoparticles of size range 50~250 nm in the extract were examined through a zeta sizer. The water absorption rate of ~660% and 17.24° water contact angle shows good hydrophilic nature and water absorbency of the nanofiber membrane. The UV-Vis also analyzed fast drug release of >70% in 5 min. The prepared membrane also exhibits 99.9% antibacterial activity against Staphylococcus aureus and has 79% antioxidant activity. Moreover, the membrane also had good mechanical properties (tensile strength 1.67 N, elongation 48%) and breathability (air permeability 15.24 mm/s). AI -incorporated nanofiber membrane can effectively be used for facial mask application.

Non-precious metal-based electrocatalysts on carbon materials with high durability and low cost have been developed to ameliorate the oxygen-reduction reaction (ORR) and oxygen-evolution reaction (OER) for electrochemical energy applications such as in fuel cells and water electrolysis. Herein, two different morphologies of FeNi/NiFe 2 O 4 supported over hierarchical N-doped carbons were achieved via carbonization of the polymer nanofibers by controlling the ratio of metal salts to melamine: a mixture of carbon nanotubes (CNTs) and graphene nanotubes (GNTs) supported over carbon nanofibers (CNFs) with spherical FeNi encapsulated at the tips (G/CNT@NCNF, 1 : 3), and graphene sheets wrapped CNFs with embedded needle-like FeNi (GS@NCNF, 2 : 3). G/CNT@NCNF shows excellent ORR activity (on-set potential: 0.948 V vs. RHE) and methanol tolerance, whilst GS@NCNF exhibited significantly lower over-potential of only 230 mV at 10 mA cm -2 for OER. Such high activities are due to the synergistic effects of bimetallic NPs encapsulated at CNT tips and N-doped carbons with unique hierarchical structures and the desired defects., Competing Interests: There are no conflicts of interest to declare., (This journal is © The Royal Society of Chemistry.)

A one-pot synthesis of bimetallic metal-organic frameworks (Co/Fe-MOFs) was achieved by treating stoichiometric amounts of Fe and Co salts with 2-aminoterephthalic acid (NH 2 -BDC). Monometallic Fe (catalyst A) and Co (catalyst F) were also prepared along with mixed-metal Fe/Co catalysts (B-E) by changing the Fe/Co ratio. For mixed-metal catalysts (B-E) SEM energy-dispersive X-ray (EDX) analysis confirmed the incorporation of both Fe and Co in the catalysts. However, a spindle-shaped morphology, typically known for the Fe-MIL-88B structure and confirmed by PXRD analysis, was only observed for catalysts A-D. To test the catalytic potential of mixed-metal MOFs, reduction of nitroarenes was selected as a benchmark reaction. Incorporation of Co enhanced the activity of the catalysts compared with the parent NH 2 -BDC-Fe catalyst. These MOFs were also tested as electrocatalysts for the oxygen evolution reaction (OER) and the best activity was exhibited by mixed-metal Fe/Co-MOF (Fe/Co batch ratio=1). The catalyst provided a current density of 10 mA cm -2 at 410 mV overpotential, which is comparable to the benchmark OER catalyst (i.e., RuO 2 ). Moreover, it showed long-term stability in 1 m KOH. In a third catalytic test, dehydrogenation of sodium borohydride showed high activity (turnover frequency=87 min -1 ) and hydrogen generation rate (67 L min -1  g -1 catalyst). This is the first example of the synthesis of bimetallic MOFs as multifunctional catalysts particularly for catalytic reduction of nitroarenes and dehydrogenation reactions., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

We report the photosensitization of electrospun titania nanofibers, with a mean diameter of 195 nm, by low bandgap silver sulfide nanoparticles of 11-23 nm mean size with the aim of treating heavy metal ions and pathogenic bacteria simultaneously under simulated solar light irradiation. The 17 nm Ag 2 S/TiO 2 nanofibers showed 90% photocatalytic reduction of Cr(vi) at pH of 3 with a pseudo-first order rate constant of 0.016 min -1 which is significantly better than the previously reported for Ag-Ag 2 S/TiO 2 composite particles. The antibacterial capability of the Ag 2 S/TiO 2 nanofibers was evaluated via photo-disinfection of the Gram-positive and Gram-negative bacterial strains. The smallest sized 11 nm Ag 2 S/TiO 2 nanofiber showed the best bactericidal efficiency of 100% and 90.6% against Gram-negative E. coli and Gram-positive S. aureus after 1 h of irradiation, respectively, whereas, only 50% E. coli and 41% S. aureus were found to be inactivated in dark. Furthermore, a UV-O 3 treatment of the 11 nm Ag 2 S/TiO 2 nanofibers remarkably enhanced the antibacterial activity where 89% E. coli and 81% S. aureus were inactivated in just 10 min of the irradiation. Enhanced photocatalytic activity is attributed to the efficient charge separation and transfer and reduced electron-hole recombination induced by the effective heterojunction formation between TiO 2 and the optimally sized Ag 2 S nanoparticles. The disinfection nature of the Ag 2 S nanoparticles, role of the generated hydroxyl species under irradiation, and the cell wall damage mechanism is also discussed. This study demonstrates the potential use of these multifunctional composite TiO 2 nanofibers for water remediation., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

TiO 2 nanofibers, with mean diameter ~200 nm, were fabricated by electrospinning and successfully photosensitized with low bandgap Ag 2 S nanoparticles of 11, 17, 23 and 40 nm mean sizes, with corresponding loading of 4, 10, 18 and 29 wt.% Ag 2 S, respectively. 17 nm Ag 2 S@TiO 2 nanofibers exhibited optimal activity in the photodegradation of methylene blue under simulated sunlight with pseudo-first order rate constant of 0.019 min -1 compared to 0.009 min -1 for pure TiO 2 nanofibers. In spite of greater visible-light absorption and reduced bandgap, larger than 17 nm Ag 2 S nanoparticles exhibited sluggish photodegradation kinetics probably due to less photo-induced carriers generation in TiO 2 and reduced electron injection rates from the larger sized Ag 2 S into TiO 2 . Furthermore, a UV-O 3 surface treatment induced excess Ti 3+ surface states and oxygen vacancies which synergistically enhanced the photodegradation rate constant to 0.030 min -1 for 17 nm Ag 2 S@TiO 2 sample which is ~70% better than the previously reported for Ag 2 S/TiO 2 hierarchical spheres. This was attributed to the efficient charge separation and transfer driven by increased visible-light absorption, bandgap narrowing and reduced electron-hole recombination rates. The present study demonstrate the potential utilization of Ag 2 S@TiO 2 nanofibers in filtration membranes for removal of organic pollutants from wastewater.