This study involves the novel fabrication of a high responsivity, fast response, and low-cost (UV) photodetector (PD) based on ZnO/Ni nanoparticles deposited on a glass substrate. The ZnO/Ni nanoparticles were synthesized using a polyol process. The structure and the morphology of the samples were characterized by X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). Optical properties were measured using UV-visible, diffuse reflectance and photoluminescence (PL) spectroscopy. The photodetector exhibited high photoresponse characteristics under 375 nm laser excitation. Our device shows a high responsivity (121 A W⁻¹) with rise time (about 5.52 s) and fall time (about 12 s) at a bias voltage of 1 V. The device exhibits excellent reproducibility and stability characteristics with time. The noise spectra obtained from the UV photodetector were caused by the 1/f noise. The noise-equivalent power (NEP) is 1.08 × 10⁻⁹ W. Thus, the polyol process can be a useful and effective method for improving the performance of ZnO/Ni UV photodetectors.

Synthesis of titanium dioxide (TiO₂) nanoparticles by a new one-pot solvothermal process.

Little information is available on the potential ecotoxicity of nanomaterials in the marine environment. In particular, the aquatic ecotoxicity impact of titanium dioxide (TiO₂) has been rarely reported. To carefully address this issue, we report on the synthesis of TiO₂ NPs using solvothermal process. The structure and morphology of the prepared TiO₂ nanoparticles were characterised using different techniques. To study the potential ecotoxicity effect of TiO₂, antioxidant system of mediterranean bivalves (Mytilus galloprovincialis) was used, measuring three oxidative biomarkers (ROS production, SOD activity and GSH/GSSG level). No considerable effect was found in the digestive glands of any of the groups treated with TiO₂ with concentration gradients ranging from 1 to 100 mg/L. Thus, the level of the superoxide anion, the activity of an antioxidant enzyme superoxide dismutase (SOD) and the GSH/GSSG ratio showed no significantly differences in digestive glands of all treated groups compared to the control. However, slight modifications were observed in the gills at high concentrations. These results demonstrated that TiO₂ appears to exert little toxicity on marine mussels after a short-term exposure at high concentration. However, before considering the use of this nanomaterial in various applications, further complementary studies are required in order to ensure the environmental safety of these NPs.

In this work, PdO/TiO₂ and Eu₂O₃/TiO₂ nanocomposites (NCs) were synthesized using a new facile, template‐free, and one‐step solvothermal approach and characterized by several instrumentation techniques. X‐ray photoelectron spectroscopy studies revealed the presence of oxidized form of the Pd and Eu nanoparticles within the NC materials (PdO and Eu₂O₃). The two catalysts exhibited remarkable activity for the hydrogen evaluation reaction (HER) in a strong alkaline solution (4.0 M NaOH) with PdO/TiO₂ catalyst being the best, which recorded an exchange current density (j_o) of 0.26 mA cm⁻² and a Tafel slope (β_c) of 125 mV dec⁻¹. Such parameters are not far from those recorded for a commercial Pt/C catalyst (0.71 mA cm⁻² and 120 mV dec⁻¹) performed here under the same operating conditions. Eu₂O₃/TiO₂ catalyst recorded j_o and β_c values of 0.05 mA cm⁻² and 135 mV dec⁻¹. The Tafel slopes 125 and 135 mV dec⁻¹ calculated on the PdO/TiO₂ and Eu₂O₃/TiO₂ catalysts suggest a HER kinetics controlled by the Volmer step. PdO/TiO₂ catalyzed the HER with a high turnover frequency of 2.3 H₂/s at 0.2 V versus the reversible hydrogen electrode, while Eu₂O₃/TiO₂ catalyst only measured a turnover frequency value of 1.25 H₂/s at the same overpotential. The two catalysts exhibited excellent stability and durability after 10 000 cycles and 72 hours of controlled potential electrolysis at a high cathodic overpotential, reflecting their practical applicability. Scanning electron microscope and X‐ray photoelectron spectroscopy examinations revealed that the morphology and chemistry of both catalysts were not altered as a result of the performed long‐term stability and durability tests.