Abstract
Many low-dimensional nanostructured metal oxides (MOXs) with impressive room-temperature gas-sensing characteristics have been synthesized, yet transforming them into relatively robust bulk materials has been quite neglected. Pt-decorated SnO2 nanoparticles with 0.25–2.5 wt% Pt were prepared, and highly attractive room-temperature hydrogen-sensing characteristics were observed for them all through pressing them into pellets. Some pressed pellets were further sintered over a wide temperature range of 600–1200 °C. Though the room-temperature hydrogen-sensing characteristics were greatly degraded in many samples after sintering, those samples with 0.25 wt% Pt and sintered at 800 °C exhibited impressive room-temperature hydrogen-sensing characteristics comparable to those of their counterparts of as-pressed pellets. The variation of room-temperature hydrogen-sensing characteristics among the samples was explained by the facts that the connectivity between SnO2 grains increases with increasing sintering temperature, and Pt promotes oxidation of SnO2 at high temperatures. These results clearly demonstrate that some low-dimensional MOX nanocrystals can be successfully transformed into bulk MOXs with improved robustness and comparable room-temperature gas-sensing characteristics.
Highlights
With such advantages as high sensitivity, high stability, simple operation and low cost gas sensors based on SnO2 porous thick films are widely applied for the detection of many reducing gases, including hydrogen and carbon monoxide [1]
When the liquids are removed through evaporation, metal oxides (MOXs) nanocrystals are in adequately good contact with one another and with electrodes, and prototypal sensors are fabricated to be suitable for gas-sensing measurement
According to the evolution of the room-temperature hydrogen-sensing characteristics among the samples, it is clearly revealed that the connectivity between SnO2 grains increases with increasing sintering temperature, and Pt promotes oxidation of SnO2 at high temperatures
Summary
With such advantages as high sensitivity, high stability, simple operation and low cost gas sensors based on SnO2 porous thick films are widely applied for the detection of many reducing gases, including hydrogen and carbon monoxide [1]. While many low-dimensional MOX nanocrystals are very attractive for room-temperature gas sensing, it is a great challenge to characterize their gas-sensing capabilities individually They are dispersed in some liquids and dropped on substrates with inter-digital electrodes or mixed with liquids to form pastes and screen-printed on substrates with electrodes. When the liquids are removed through evaporation, MOX nanocrystals are in adequately good contact with one another and with electrodes, and prototypal sensors are fabricated to be suitable for gas-sensing measurement. In this way, highly impressive room-temperature gas-sensing capabilities have been successfully observed for many lowdimensional MOX nanocrystals, such as Pd-decorated SnO2 nanowires [4], Pd-decorated
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