Plant-mediated Z-scheme ZnO/TiO2-NCs for antibacterial potential and dye degradation: experimental and DFT study.

Efficient separation of electron-hole pairs remains pivotal in optimizing photogenerated carrier functionality across diverse catalytic and optoelectronic systems. This study presents the fabrication of a novel hollow direct Z-scheme photocatalyst, ZnO/TiO2. A thorough analysis encompassing various techniques such as Ultraviolet-Visible Spectroscopy (UV-Vis), X-ray Diffraction (XRD), Transmission electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FT-IR), Thermogravimetric Analysis (TGA), and Energy-Dispersive X-ray Spectroscopy (EDX) provided detailed insights into the complex material characteristics of the ZnO/TiO2 heterojunction catalyst. The findings revealed coexisting anatase TiO2 and wurtzite ZnO phases, each retaining distinct attributes within the nanocomposites (NCs) structure. The study showcased the photocatalytic efficacy of ZnO/TiO2-NCs in decomposing Methylene Blue and Acridine Orange under UV irradiation, correlated with their underlying structures. Enhanced degradation of these dyes resulted from the establishment of a direct Z-scheme heterojunction between ZnO and TiO2. Employing Density Functional Theory (DFT) using Quantum ESPRESSO, this research analyzed phase diagrams and band structures, elucidating electronic properties and structural correlations. The study characterized a ZnO/TiO2 composite, revealing a band gap of 3.1-3.3 eV through UV-Visible spectroscopy and confirming its formation without impurity phases via XRD analysis. TEM and EDX showed uniform element dispersion (Zn: 27%, Ti: 29.62%, C: 5.03%, O: 38.35%). Computational analysis using DFT indicated a reduction in stable phases with increasing temperature. Enhanced dye degradation was observed (MB: 88.9%, AO: 84%), alongside significant antibacterial activity. In the future we predict that research will focus on development of scaled up production and photocatalytic activity through surface modification, while unveiling mechanistic insights and environmental applicability for multifunctional use in water treatment and antibacterial applications, leading to further advancement of the field.

Anti-saprolegnia potency of some plant extracts against Saprolegnia diclina, the causative agent of saprolengiasis.

Saprolegnosis of fresh water fishes caused by Saprolegnia diclina often results in serious economic losses to fish hatcheries. Despite the proven efficiency of malachite green as a potential fungicide in prevention and control of fish saprolegnosis, there is a strong debate about its safety aspects in use since it was documented to be responsible for many carcinogenic and teratogenic attributes. Bioactivity of four ethanolic plant extracts were assessed to attain a natural alternative to the traditional fungicide currently used in saprolegnosis control. Ethanolic extracts of Punica granatum and Thymus vulgaris exhibited a potential efficacy in suppressing mycelial growth of S. diclina at concentration of 0.5 mg/ml while extracts of Nigella sativa and Zingiber officinales were not effective respectively. The extract of pomegranate showed the highest antifungal potency with minimum inhibitory concentration (MIC) of 200 ppm while thyme extract was less effective and recorded MIC of 400 ppm against S. diclina. The acute fish toxicity of the plant extracts indicated the low toxicity of P. granatum and T. vulgaris extracts as no fish mortalities were detected at aquaria containing 200, 400 and 800 ppm of plant extracts respectively. Considering the low toxicity of these plant extracts, it may be concluded that 200 and 400 ppm of pomegranate and thyme extracts which suppressed the mycelial growth of the S. diclina could be safely used for saprolegniasis control. Both of pomegranate and thyme extracts which proved to possess a potential antifungal activity can be considered as a natural alternative fungicides to control saprolegniasis avoiding carcinogenic malachite green application.

Facile sonochemical synthesis of rutile-type titanium dioxide microspheres decorated graphene oxide composite for efficient electrochemical sensor.

In this reports the facile and green synthesis of rutile-type titanium dioxide nanoparticles decorated graphene oxide nanocomposite via the ultrasonication process (frequency: 50 kHz, Power: 100 W/cm2 and Ultrasonic type: Ti-horn). Because, the sonochemical synthesis method is simple, non-explosive and harmless method than other conventional technique. Furthermore, the synthesized material was characterized by various analytical techniques including FESEM, EDX, XRD, EIS and electrochemical methods. Then, the synthesized TiO2 MPs@GOS composite was applied for the electrocatalytic detection of theophylline (TPL) using CV and amperometric (current-time) techniques. Captivatingly, the modified sensor has excellent electrocatalytic performance with the wider linear range from 0.02 to 209.6 µM towards the determination of theophylline and the LOD and sensitivity of the modified sensor was calculated as 13.26 nM and 1.183 µA·µM-1·cm-2, respectively. In addition, a selectivity, reproducibility and stability of the TiO2 MPs@GOS modified GCE were analyzed towards the determination of theophylline molecule. Finally, the real time application of TiO2 MPs@GOS modified theophylline sensor was established in serum and drug samples.