Improving food preservation technologies is a key aspect in the struggle to reduce global food waste, and natural antimicrobial substances, such as essential oil (EO) components represent very promising food preserving agent. However, their intrinsic chemico-physical properties, such as the low melting point, low water solubility and high volatility, pose some practical difficulties in exploiting them for practical applications. Cocrystallization is used to stabilize liquid or volatile EO components providing them whit a crystalline environment, thus improving their potential application as antibacterial agents. Five EO active ingredients (THY = thymol, CAR = carvacrol, EUG = eugenol, CAD = trans-cinnamaldehyde, and VAN = o-vanillin) and two coformers (INA = Isonicotinamide, and HBA = 4-hydroxybenzoic acid) have been combined and the corresponding cocrystals have been studied for their potential inhibiting effect against four food spoilage bacteria (Bacillus thuringiensis, Enterobacter cloacae, Pseudomonas fluorescens, and Serratia marcescens). The structures of the five cocrystals have been used to derive structure-activity relationships in terms of release energy of the active ingredients form the crystalline environment, and a correlation has been derived with the Intermolecular Interaction Energies of the EO molecules.
Cerium-containing titania nano-octahedra (CeTNOh) are obtained by ultrasonication-hydrothermal synthesis of Ce-containing titanate nanowires (0.35, 0.46, and 0.70 Ce mol %) from commercial TiO2 (Degussa P25). CeTNOh are tested as photocatalysts to degrade a target pollutant (ciprofloxacin) under simulated solar light and at mild conditions. CeTNOh are anatase polymorphs with increasing crystallite size as Ce content increases. Hydrothermal treatments enhance the specific surface area (SSA) compared to P25, although Ce addition slightly reduces SSA while increasing crystallite size. Electron Microscopy confirms the morphology, although higher Ce levels hinder a full transformation. X-ray photoemission spectroscopy (XPS) shows the presence of Ce3+/Ce4+ redox pair, promoting electron mobility and Ti-Ce interactions. Optical and electronic spectroscopy reveals that Ce loading reduces the bandgap from 3.20 to 2.74 eV, extending light absorption into the visible range, thus enhancing the photocatalytic activity. The best sample, CeTNOh0.35, achieved 83% degradation of ciprofloxacin after 360 minutes under solar irradiation, with poor adsorption in the dark period. Higher Ce loadings negatively affect photoactivity by partially covering titania active sites. Reusability tests confirm the stability and efficiency of CeTNOh0.35 over three cycles, highlighting the importance of octahedral morphology in Ce-containing systems to boost the final photoactivity for water remediation.
Advanced lithium-ion batteries (LIBs) for electric vehicle applications are on demand recently. Graphite anode in LIBs provides with good cycle life but limited capacity. On the other hand, silicon that possesses high capacity but significant volume changes during cycling limits its practical use. Hence, nanocomposites of graphite and nano silicon (nSi) can provide a viable solution. This work emphasizes the potential of recycled spent graphite (SG) composited with nSi anode in order to fulfill the demand for high capacity anodes. SG to nSi ratio is systematically designed of the composite for LIB applications. The structural, morphological, and surface chemical analysis are conducted and further correlated with the electrochemical performances of the composite anodes. The nanocomposite with equal ratio of SG:nSi (1:1) exhibited high reversible capacity of 1886 mAh g−1 while the SG dominant ratio of SG:nSi (3:1) delivered a least capacity loss of less than 2.2 mAh g−1 cycle−1 for 200 cycles. Nanocomposites exhibited satisfactory electrochemical performance; especially improving cycling stability. The enhanced performance is attributed to the stable solid-electrolyte interface layer formation which is further characterized by ex situ X-ray Photoelectron Spectroscopy analysis with different state of charge and discharge conditions.