Continuous monitoring of greenhouse gases with high spatio-temporal resolution has lately become an urgent task because of tightening environmental restrictions. It may be addressed with an economically efficient solution, based on semiconductor metal oxide gas sensors. In the present work, CO₂ detection in the relevant concentration range and ambient conditions was successfully effectuated by fine-particulate La₂O₃-based materials. Flame spray pyrolysis technique was used for the synthesis of sensitive materials, which were studied with X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs) and low temperature nitrogen adsorption coupled with Brunauer–Emmett–Teller (BET) effective surface area calculation methodology. The obtained materials represent a composite of lanthanum oxide, hydroxide and carbonate phases. The positive correlation has been established between the carbonate content in the as prepared materials and their sensor response towards CO₂. Small dimensional planar MEMS micro-hotplates with low energy consumption were used for gas sensor fabrication through inkjet printing. The sensors showed highly selective CO₂ detection in the range of 200–6667 ppm in humid air compared with pollutant gases (H₂ 50 ppm, CH₄ 100 ppm, NO₂ 1 ppm, NO 1 ppm, NH₃ 20 ppm, H₂S 1 ppm, SO₂ 1 ppm), typical for the atmospheric air of urbanized and industrial area.

In this work, we primarily aimed to study the Nb(V) doping effect on the surface activity and optical and electrical properties of nanocrystalline TiO₂ 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. It was found that the TiO₂-Nb-4 material demonstrated a higher conversion of acetone at a temperature of 300 °C than pure TiO₂, which was due to the presence of more active forms of chemisorbed oxygen, as well as higher Lewis acidity of the surface. Conduction activation energies (E_act) were calculated for thin films based on TiO₂-Nb materials. The results of the MB photobleaching experiment showed a non-monotonic change in the photocatalytic properties of materials with an increase in Nb(V) content, which was caused by a combination of factors, such as specific surface area, phase composition, concentration of charge carriers as well as their recombination due to lattice point defects.

The C-V curve is an important characteristic of a MEMS microphone as it determines its operating voltage and sensitivity. Due to the complicated geometry of its fixed perforated backplate and thin...

Сформирован массив данных, включающий сопротивления трех сенсоров МЭМС- конструкции при различных концентрациях сероводорода ниже 1 млн–1 в среде реального городского воздуха. Выделены значимые признаки, коррелирующие с концентрацией. Проведена оценка различ- ных моделей машинного обучения для задач классификации и регрессии.