Photoelectrocatalytic Activity of ZnO-Modified Hematite Films in the Reaction of Alcohol Degradation

Thin-film nanocrystalline hematite electrodes were fabricated by electrochemical deposition and loaded with electrodeposited zinc oxide in various amounts. Under visible light illumination, these electrodes demonstrate high activity in the photoelectrochemical degradation of methanol, ethylene glycol and, in particular, glycerol. Results of intensity-modulated photocurrent spectroscopy show that the photoelectrocatalysis efficiency is explained by the suppression of the electron-hole pair recombination and an increase in the rate of photo-induced charge transfer. Thus, zinc oxide can be considered an effective modifying additive for hematite photoanodes.

Obtaining of ZnO/Fe2O3 Thin Nanostructured Films by AACVD for Detection of ppb-Concentrations of NO2 as a Biomarker of Lung Infections

ZnO/Fe₂O₃ nanocomposites with different concentration and thickness of the Fe₂O₃ layer were obtained by two-stage aerosol vapor deposition (AACVD). It was shown that the ZnO particles have a wurtzite structure with an average size of 51-66 nm, and the iron oxide particles on the ZnO surface have a hematite structure and an average size of 23-28 nm. According to EDX data, the iron content in the films was found to be 1.3-5.8 at.%. The optical properties of the obtained films were studied, and the optical band gap was found to be 3.16-3.26 eV. Gas-sensitive properties at 150-300 °C were studied using a wide group of analyte gases: CO, NH₃, H₂, CH₄, C₆H₆, ethanol, acetone, and NO₂. A high response to 100 ppm acetone and ethanol at 225-300 °C and a high and selective response to 300-2000 ppb NO₂ at 175 °C were established. The effect of humidity on the magnitude and shape of the signal obtained upon NO₂ detection was studied.

Gas-Sensitive Properties of ZnO/Ti2CTx Nanocomposites

At present, a new class of 2D nanomaterials, MXenes, is of great scientific and applied interest, and their application prospects are very broad, including as effective doping components for receptor materials of MOS sensors. In this work we have studied the influence on the gas-sensitive properties of nanocrystalline zinc oxide synthesized by atmospheric pressure solvothermal synthesis, with the addition of 1-5% of multilayer two-dimensional titanium carbide Ti₂CT_x, obtained by etching Ti₂AlC with NaF solution in hydrochloric acid. It was found that all the obtained materials have high sensitivity and selectivity with respect to 4-20 ppm NO₂ at a detection temperature of 200 °C. It is shown that the selectivity towards this compound is best for the sample containing the highest amount of Ti₂CT_x dopant. It has been found that as the MXene content increases, there is an increase in nitrogen dioxide (4 ppm) from 1.6 (ZnO) to 20.5 (ZnO-5 mol% Ti₂CT_x). reactions which the responses to nitrogen dioxide increase. This may be due to the increase in the specific surface area of the receptor layers, the presence of MXene surface functional groups, as well as the formation of the Schottky barrier at the interface between the phases of the components.

Synthesis, structures and luminescence of multinuclear silver(i) pyrazolate adducts with 1,10-phenanthroline derivatives

A set of silver(i) 3,5-bis(trifluoromethyl) pyrazolate adducts with 1,10-phenanthroline (L²), 2,9-dimethyl-1,10-phenanthroline (neocuproine, L³) and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (bathocuproine, L⁴) was synthesized starting from trimeric silver pyrazolate Ag₃Pz₃. Reactions with sterically hindered L³ and L⁴ cause the destruction of the original trimeric core, yielding a dinuclear Ag₂Pz₂ cycle with an unprecedented chair configuration for L³, while bathocuproine L⁴ leads to the drastic rearrangement of the silver pyrazolate core into cationic Ag(L⁴)₂ and anionic Ag₅Pz₆ subunits. All complexes obtained exhibit phosphorescence in the solid state. Time-dependent density functional theory calculations demonstrate their different possible emission processes, explaining their emission behavior as well as their lifetimes.