Synergistic Effect of Nanocrystalline SnO2 Sensitization by Bimetallic Au and Pd Modification via Ingle Step Flame Spray Pyrolysis Technique

Convenient and scalable single step flame spray pyrolysis (FSP) synthesis of bimetal AuPd sensitized nanocrystalline SnO2 for gas sensor application is reported. The materials chemical composition, structure and morphology has been studied by XRD, XPS, HAADFSTEM, BET, ICP-MS techniques as well as thermo-programmed reduction with hydrogen (TPR-H2). Superior gas sensor response of bimetal modified SnO2 towards wide concentration range of reducing (CO, CH4, C3H8, H2S, NH3) and oxidizing (NO2) gases compared to pure and monometallic modified SnO2 is reported. The observed enhanced gas sensor performance is concluded to arise from combination of facilitated oxygen molecule spillover on gold particles and electronic effect of Fermi level control by reoxidizing Pd-PdO clusters, homogeneously distributed over SnO2 particles surface

Selective Detection of Hydrocarbons in Real Atmospheric Conditions by Single MOX Sensor in Temperature Modulation Mode

Selective detection of hydrocarbons – methane and propane – in urban air for industrial safety properties by single metal oxide semiconductor gas sensor has been demonstrated. As sensors were fabricated on the basis of nanocrystalline SnO2 and alumina micro-hotplates. Sensor working temperature modulation has been applied during raw sensor data collection. Pre-processing of acquired data – scaling, baseline extraction and exclusion of non-valid data points has been demonstrated to be critical procedures before application of machine learning algorithms. The achieved accuracy of 86% for correct gas identification in 40-200 ppm range has been demonstrated

Light—Assisted Low Temperature Formaldehyde Detection at Sub-ppm Level Using Metal Oxide Semiconductor Gas Sensors

Formaldehyde HCOH is a toxic compound that, in trace concentrations, causes serious diseasesof the respiratory tract, gastrointestinal tract and eyes [...

Selectivity Modification of SnO2-Based Materials for Gas Sensor Arrays

An enhancement of selectivity of sensor materials, based on nanocrystalline SnO2 is reported. Selectivity toward target gases such as CO, NO2, NH3, H2S and acetone vapor, could be achieved by selection of catalytic cluster distributed over the surface of thick film material. Presented results allow us to propose application of obtained materials in "electronic nose" sensor systems

Nanocomposites SnO₂/SiO₂ for CO Gas Sensors: Microstructure and Reactivity in the Interaction with the Gas Phase

Nanocomposites SnO2/SiO2 with a silicon content of [Si]/([Sn] + [Si]) = 3/86 mol.% were obtained by the hydrothermal method. The composition and microstructure of the samples were characterized by EDX, XRD, HRTEM and single-point Brunauer-Emmet-Teller (BET) methods. The surface sites were investigated using thermal analysis, FTIR and XPS. It is shown that the insertion of silicon dioxide up to the value of [Si]/([Sn] + [Si]) = 19 mol.% stabilizes the growth of SnO2 nanoparticles during high-temperature annealing, which makes it possible to obtain sensor materials operating stably at different temperature conditions. The sensor properties of SnO2 and SnO2/SiO2 nanocomposites were studied by in situ conductivity measurements in the presence of 10–200 ppm CO in dry and humid air in the temperature range of 150–400 °C. It was found that SnO2/SiO2 nanocomposites are more sensitive to CO in humid air as compared to pure SnO2, and the sample with silicon content [Si]/([Sn] + [Si]) = 13 mol.% is resistant to changes in relative air humidity (RH = 4%–65%) in the whole temperature range, which makes it a promising sensor material for detecting CO in real conditions. The results are discussed in terms of the changes in the composition of surface-active groups, which alters the reactivity of the obtained materials