ZnO/MO Nanofiber Heterostructures: MO Receptor's Role in Gas Detection.

ZnO/MO (M = Fe, Co, Ni, Sn, In, Ga; [M]/([Zn] + [M]) = 15 mol%) nanofiber heterostructures were obtained by co-electrospinning and characterized by X-ray diffraction, scanning electron microscopy and X-ray fluorescence spectroscopy. The sensor properties of ZnO and ZnO/MO nanofibers were studied toward reducing gases CO (20 ppm), methanol (20 ppm), acetone (20 ppm), and oxidizing gas NO (1 ppm) in dry air. It was demonstrated that the temperature of the maximum sensor response of ZnO/MO nanofibers toward reducing gases is primarily influenced by the binding energy of chemisorbed oxygen with the surface of the modifier's oxides.

Cr-Doped Nanocrystalline TiO-CrO Nanocomposites with p-p Heterojunction as a Stable Gas-Sensitive Material.

Nanocrystalline TiO is a perspective semiconductor gas-sensing material due to its long-term stability of performance, but it is limited in application because of high electrical resistance. In this paper, a gas-sensing nanocomposite material with p-p heterojunction is introduced based on p-conducting Cr-doped TiO in combination with p-conducting CrO. Materials were synthesized via a single-step flame spray pyrolysis (FSP) technique and comprehensively studied by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) specific surface area analysis, transition electron microscopy (TEM), energy dispersive X-ray (EDX) spectroscopy, X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), and Raman spectroscopy.

Effect of Donor Nb(V) Doping on the Surface Reactivity, Electrical, Optical and Photocatalytic Properties of Nanocrystalline TiO.

In this work, we primarily aimed to study the Nb(V) doping effect on the surface activity and optical and electrical properties of nanocrystalline TiO obtained through flame-spray pyrolysis. Materials were characterized using X-ray diffraction, Raman spectroscopy and IR, UV and visible spectroscopy. The mechanism of surface reaction with acetone was studied using in situ DRIFTs.

Highly Active Nanocrystalline ZnO and Its Photo-Oxidative Properties towards Acetone Vapor.

Zinc oxide is one of the well-known photocatalysts, the potential applications of which are of great importance in photoactivated gas sensing, water and air purification, photocatalytic synthesis, among others. However, the photocatalytic performance of ZnO strongly depends on its morphology, composition of impurities, defect structure, and other parameters. In this paper, we present a route for the synthesis of highly active nanocrystalline ZnO using commercial ZnO micropowder and ammonium bicarbonate as starting precursors in aqueous solutions under mild conditions.