Preparation of ZnO/NiO-loaded flexible cellulose nanofiber film electrodes and their application to dye-sensitized solar cells

Antibacterial food packaging using biocompatible nickel oxide-infused cellulose acetate electrospun nanofibers

The present study included the environmentally friendly production of stable nickel nanoparticles (NiO NPs) using lemon and tomato, followed by their analysis and evaluation for their antibacterial properties against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and Bacillus cereus. The Nickel oxide nanoparticles produced exhibited their maximum absorption at 276 nm in the UV-vis spectrum. The image captured FESEM revealed smooth nanofibers with an average diameter of around 259 ± 3.7 nm. X-ray diffraction (XRD) experiments verified the existence of elemental nickel and accurately determined the crystalline structure of nickel oxide nanoparticles. Novel green organic-inorganic hybrid nanofibers (NiO@CA) were synthesized using the electrospinning technique. These nanofibers are composed of NiO nanoparticles integrated into cellulose acetate nanofibers, which are particularly engineered for the purpose of fruit preservation. Robust antibacterial activity was shown by NiO nanoparticles and NiO@CA nanofiber against the assessed food pathogenic bacterial strains. NiO@CA nanofiber used as a surface coating on lemon and tomato prolonged their shelf life by preventing the degradation caused by food risks. The provided results indicate that NiO@CA nanofiber has the capacity to function as antimicrobial packaging for the purpose of food preservation. Enhancing food safety, prolonging shelf life, and offering an eco-friendly alternative to traditional materials, antibacterial food packaging made of biocompatible nickel oxide-infused cellulose acetate electrospun nanofibers is a great solution.

Nanoarchitectonics of Nanocellulose Filament Electrodes by Femtosecond Pulse Laser Deposition of ZnO and In Situ Conjugation of Conductive Polymers

Electroactive filament electrodes were synthesized by wet-spinning of cellulose nanofibrils (CNF) followed by femtosecond pulse laser deposition of ZnO (CNF@ZnO). A layer of conducting conjugated polymers was further adsorbed by in situ polymerization of either pyrrole or aniline, yielding systems optimized for electron conduction. The resultant hybrid filaments were thoroughly characterized by imaging, spectroscopy, electrochemical impedance, and small- and wide-angle X-ray scattering. For the filaments using polyaniline, the measured conductivity was a result of the synergy between the inorganic and organic layers, while the contribution was additive in the case of the systems containing polypyrrole. This observation is rationalized by the occurrence of charge transfer between ZnO and polyaniline but not that with polypyrrole. The introduced conductive hybrid filaments displayed a performance that competes with that of metallic counterparts, offering great promise for next-generation filament electrodes based on renewable nanocellulose.

Green Synthesis of Nickel Oxide NPs Incorporating Carbon Dots for Antimicrobial Activities

A biosynthesis composite using the green synthesis of titled metal nanoparticles (nickel oxide nanoparticles, NiO NPs, and carbon dots, C-dots) was produced, characterized, and then applied for antimicrobial activities. NiO NPs were produced using the Croton macrostachyus (Bakkannisa) plant leaf extract and nickel nitrate (III) hexahydrate [Ni(NO3)2·2H2O] as precursors, while C-dots were produced using citric acid and o-phenylenediamine (o-OPD). The distribution of the average particle size of the NiO NPs and NiO NPs@C-dots was 25.34 ± 0.12 and 24.95 ± 0.22 nm, respectively. The antimicrobial effects of the prepared materials were tested against the selected bacterial and fungal strains. Based on the outcomes of the bioassay, it was realized that both the bare and composite materials were effective against all bacterial strains. The composite's high surface area with strong inhibitive effective antimicrobial effects against bacterial and fungal strains were observed. Therefore, strong inhibitive effects of 21-24 and 22-26 mm were observed with NiO NPs and NiO NPs@C-dots, respectively.

Modification of Flexible Electrodes for P-Type (Nickel Oxide) Dye-Sensitized Solar Cell Performance Based on the Cellulose Nanofiber Film

The preparation of flexible electrode, including working electrode (WE) and counter electrode (CE), for dye-sensitized solar cells (DSSCs) utilizing metal oxides using environmentally friendly sustainable TEMPO-oxidized cellulose nanofibers (TOCNFs) is reported in this work. A new type of flexible electrode for the DSSCs, which were made of cellulose nanofiber composites with nickel hydroxide [CNF/Ni(OH)₂] substrate films and cellulose nanofiber composites with polypyrrole (CNF/PPY). Nickel hydroxide, Ni(OH)₂, has been prepared hydrothermally in the presence of TOCNFs, [TOCNF@Ni(OH)₂]. Similarly, the conductive polymer substrate has also been prepared from a composite consisting of TOCNF and PPY, TOCNF@ PPY film, by means of polymerization for the CE. Overall, the prepared electrodes both WE from CNF/Ni(OH)₂ substrates and CE from the TOCNF@PPY substrate film were revealed as the novelty of this work and which no one has introduced previously. Although NiO nanoparticles (NPs) coated on the Ni(OH)₂/TOCNF electrode also produced a good power conversion efficiency, PCE (0.75%); nevertheless, the NiO NP treatment with carbon dots boosted the efficiency up to 1.3%.