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We prepared platinum nanoparticle ink usable for the fabrication of MEMS microheatersof high-temperature gas sensors and thermoresistors operating up to 450 °C and present somepreliminary results on the application of the ink in sensor microheater manufacturing. The inkconsists of platinum particles (3⁻8 nm) suspended in ethylene glycol solution of polyvinylpyrrolidone.The ink is usable in both InkJet and AerosolJet printers. The annealing at temperature of about 600 °Cleads to the formation of uniform microheater structure. The experiments on microheater agingconfirm the stability of the printed microstructure at 450 °C for at least one year of operation. Thesubstrates used for printing were thin alumina and LTCC ceramics with thickness of 12⁻20 μm.

The perspective catalysts usable for the fabrication of thermocatalytic gas sensors were studied. The analysis of CO oxidation kinetics by Pd decorated Al2O3, ZSM-5, SnO2, CeO2/ZrO2 and some other carriers of catalysts showed that the application of these catalysts leads to the ambiguity of sensor response (light-off effect). It was demonstrated that a catalyst based on CeO2/ZrO2 carrier could be used for the fabrication of sensors characterized by the univocal correspondence between CO concentration and sensor response. The developed model of the CO oxidation on all Pd catalysts with inert carrier enabled the description of the CO oxidation using a single value of activation energy.

Selective analysis of CO gas, hydrogen and hydrogen sulfide was carried out using single metal oxide sensor. Non-stationary sensor heating mode allowed discovering individual peculiarities of each gas in question. Resistance vs. time curves were converted into multidimensional data arrays and processed by chemometrics methods; as a result, qualitative and quantitative analysis of single-component gas systems was successfully carried out.

In this work we present the results on the application of additive technology that is aerosol and ink jet technique for the fabrication of high-temperature metal oxide gas sensors. The application of thin (12 μm) alumina membrane, aerosol jet printing of Pt microheater (line width 40–60 μm), printed sensing layer made of nanocristalline tin dioxide based material, laser cutting of the membrane enabled the fabrication of full-printed cantilever-shaped high-temperature sensor with optimal power consumption (~80 mW at 450 °C) applicable in wireless instruments for the detection of combustible and toxic gases including methane.

The application of gas sensors in breath analysis is an important trend in the early diagnostics of different diseases including lung cancer, ulcers, and enteric infection. However, traditional methods of synthesis of metal oxide gas-sensing materials for semiconductor sensors based on wet sol-gel processes give relatively high sensitivity of the gas sensor to changing humidity. The sol-gel process leading to the formation of superficial hydroxyl groups on oxide particles is responsible for the strong response of the sensing material to this factor. In our work, we investigated the possibility to synthesize metal oxide materials with reduced sensitivity to water vapors. Dry synthesis of SnO2 nanoparticles was implemented in gas phase by spark discharge, enabling the reduction of the hydroxyl concentration on the surface and allowing the production of tin dioxide powder with specific surface area of about 40 m2/g after annealing at 610 &deg, C. The drop in sensor resistance does not exceed 20% when air humidity increases from 40 to 100%, whereas the response to 100 ppm of hydrogen is a factor of 8 with very short response time of about 1 s. The sensor response was tested in mixtures of air with hydrogen, which is the marker of enteric infections and the marker of early stage fire, and in a mixture of air with lactate (marker of stomach cancer) and ammonia gas (marker of Helicobacter pylori, responsible for stomach ulcers).