Search

Cerium oxide (CeO2) thin films were successfully fabricated on glass substrates via spray pyrolysis at 350°C with varying molarities (0.025, 0.05 and 0.1 M). We employed various characterisation techniques to assess how molarity influences these thin films' microstructural, optical, morphological, and surface properties. The as-synthesized samples exhibited a distinct face-centred cubic fluorite structure oriented along the (2 0 0) crystallographic plane. Raman spectroscopy provided insights into imperfections, with the longitudinal optical mode confirming the presence of oxygen vacancies. The peak asymmetry and width in the Raman spectra were associated with the existence of Ce+3 ions and oxygen vacancies. Photoluminescence spectra (PL) illustrated an excitation peak at 400 nm and two emission peaks at 525 nm and 600 nm. Our scanning electron microscopy (SEM) images illustrated how molarity affected the morphologies of the samples, while atomic force microscopy (AFM) allowed us to investigate the film's surface morphologies and roughness values. Transmittance analysis within UV-Vis spectral range indicated that these samples were transparent, with transmittance levels ranging from 20% to 60%. Furthermore, we observed a decrease in the band gap energy (Eg) with increasing molarity. These findings hold significant promise for expanding the applications of cerium oxide in technological devices. [ABSTRACT FROM AUTHOR]

Molybdenum ions with high valence states (Mo6+) can contribute to electrical conductivity and optical transmittance. For this reason, zinc oxide (ZnO) nanorods doped with molybdenum metal were fabricated on a glass substrate by ultrasonic spray pyrolysis method. The doping concentrations were between 0–10 mol%. The crystallographic properties of the resulting ZnO samples were examined by the X‐ray diffraction (XRD) technique. According to the XRD analysis, it was found that the lattice structure of the samples belonged to the hexagonal (wurtzite) unit cell. The XRD results indicated that the crystals grow in the c‐axis (002) direction. The morphological features of the obtained thin films were studied by field emission scanning electron microscopy. The energy‐dispersive X‐ray spectroscopy results displayed that the Mo ions were in the ZnO lattice. Four point probe method was used to determine the electrical conductivity properties of the samples. The 10% mol doped sample has the highest conductivity with values of between 1.58 × 10−9 and 1.58 × 10−6 (ohm‐cm)−1. The optical transmittances of the samples were measured at wavelengths between 300 and 1000 nm. It was observed that the produced films had high optical transparency which was approximately 85%. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ag-supported ZnO particles were generated using the spray pyrolysis method. • Ag/ZnO particles with high efficiency showed twice the photolysis activity of P25. • The generated particles were recovered by gravity sedimentation and reused. • Change of Ag nanoparticles was not observed after the photolysis experiment. Environmental issues caused by the rapid industrialization and urbanization of modern society are a serious problem. For example, conventional wastewater treatment technologies such as adsorption, coagulation, and filtration are expensive and cannot completely treat the discharge of organic pollutants in industrial wastewater. A promising alternative is the decomposition treatment of organic pollutants using an eco-friendly metal oxide photocatalyst. However, the rapid recombination of excited electron-holes limits the photolytic activity of semiconductor photocatalysts. This study investigates the inhibition of electron-hole recombination by supporting Ag nanoparticles on a ZnO photocatalyst. Ag/ZnO particles are generated under various conditions using ultrasonic spray pyrolysis. XRD analysis confirms the presence of Ag and ZnO crystal peaks in the generated particles. EDX mapping and STEM images show that Ag nanoparticles are well dispersed in ZnO. The photolysis rate of organic dye (rhodamine-B) is faster than that of ZnO in all Ag/ZnO particles, and particles with a 0.2 mass% silver nitrate supported on ZnO particles exhibit twice the photolysis activity of P25. Additionally, the optimal photolysis activity in 100 mL of 5 mg/L rhodamine-B aqueous solution with 10 mg of Ag/ZnO particles are confirmed and had excellent persistence and stability even during 7 reuses. [ABSTRACT FROM AUTHOR]