Photocatalytic overall water splitting has been studied extensively from the viewpoint of solar energy conversion Despite numerous attempts, none have yielded satisfactory results for the development of photocatalysts, which work under visible light irradiation to efficiently utilize solar energy We report here the first example of visible-light-driven overall water splitting on a novel oxynitride photocatalyst, a solid solution of GaN and ZnO with a band gap of 258-276 eV, modified with RuO2 nanoparticles In contrast to the conventional non-oxide photocatalysts, such as CdS, the solid solution is stable during the overall water splitting reaction This is the first example of achieving overall water splitting by a photocatalyst with a band gap in the visible light region, which opens the possibility of new non-oxide-type photocatalysts for energy conversion

GaN:ZnO Solid Solution as a Photocatalyst for Visible-Light-Driven Overall Water Splitting

In the recent past a great deal of research efforts were directed toward the development of miniaturized gas-sensing devices, particularly for toxic gas detection and for pollution monitoring. Though various techniques are available for gas detection, solid state metal oxides offer a wide spectrum of materials and their sensitivities for different gaseous species, making it a better choice over other options. In this article a critical parameter analysis of different metal oxides that are known to be sensitive to various gaseous species are thoroughly examined. This includes phase of the oxide, sensing gaseous species, operating temperature range, and physical form of the material for the development of integrated gas sensors. The oxides that are covered in this study include oxides of aluminum, bismuth, cadmium, cerium, chromium, cobalt, copper, gallium, indium, iron, manganese, molybdenum, nickel, niobium, ruthenium, tantalum, tin, titanium, tungsten, vanadium, zinc, zirconium, and the mixed or...

Oxide Materials for Development of Integrated Gas Sensors—A Comprehensive Review

The complex dielectric functions, e(E)=e1(E)+ ie2(E), of ZnO have been measured by spectroscopic ellipsometry (SE) in the photon-energy range between 1.5 and 5.0 eV at room temperature. The SE measurements are carried out on the surface parallel to the optic axis c, which allows the determination of the optical constants for light polarized perpendicular (E⊥c) and parallel to the c -axis (E//c). The measured SE spectra show the exciton peaks at ∼3.4 eV (E0 edge). These e(E) spectra are analyzed on the basis of a simplified model of the interband transitions. Excellent agreement is achieved between the calculated and experimental results over the entire range of photon energies. Dielectric-function-related optical constants, such as the complex refractive index n*(E)=n(E)+ ik(E), absorption coefficient α(E) and normal-incidence reflectivity R(E), of ZnO have also been reported.

https://iopscience.iop.org/article/10.1143/JJAP.36.6237/pdf

Optical constants of ZnO

Zinc oxide films prepared by sol-gel spin-coating

ZnO thin film sensor

Thick film polycristalline ZnO gas sensors for hydrogen partial pressure determination in hydrogen-air mixtures present at very complex kinetic behavior that demands to be thoroughly clarified in order for them to be used in practical applications. For this reason a systematic investigation has been carried out on the time and temperature dependence of the electrical conductivity of ZnO films deposited via spray pyrolysis on ceramic substrates in the temperature range 498-573 K in the presence of dispersed Pt as the catalyst

M. Palladino

Papers

Thick Film ZnO Resistive Gas Sensors Analysis of Their Kinetic Behavior