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Structural Stability and Performance of Noble Metal-Free SnO2-Based Gas Sensors.

Tricoli A - Biosensors (Basel) (2012)

Bottom Line: The effect of crystal growth during operation (TO = 320 °C) on the sensor response to ethanol has been reported, revealing possible long-term destabilization mechanisms.In particular, crystal growth and sintering-neck formation were discussed with respect to their potential to change the sensor response and calibration.Furthermore, the effect of SiO2 cosynthesis on the cross-sensitivity to humidity of these noble metal-free SnO2-based gas sensors was assessed.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical and Process Engineering, ETH Zurich, CH-8092 Zurich, Switzerland. atricoli@ethz.ch.

ABSTRACT
The structural stability of pure SnO2 nanoparticles and highly sensitive SnO2-SiO2 nanocomposites (0-15 SiO2 wt%) has been investigated for conditions relevant to their utilization as chemoresistive gas sensors. Thermal stabilization by SiO2 co-synthesis has been investigated at up to 600 °C determining regimes of crystal size stability as a function of SiO2-content. For operation up to 400 °C, thermally stable crystal sizes of ca. 24 and 11 nm were identified for SnO2 nanoparticles and 1.4 wt% SnO2-SiO2 nanocomposites, respectively. The effect of crystal growth during operation (TO = 320 °C) on the sensor response to ethanol has been reported, revealing possible long-term destabilization mechanisms. In particular, crystal growth and sintering-neck formation were discussed with respect to their potential to change the sensor response and calibration. Furthermore, the effect of SiO2 cosynthesis on the cross-sensitivity to humidity of these noble metal-free SnO2-based gas sensors was assessed.

No MeSH data available.


Response of a gas sensor made of as prepared 1.4 wt% SnO2-SiO2 nanocomposites to increasing EtOH concentrations in dry air.
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biosensors-02-00221-f007: Response of a gas sensor made of as prepared 1.4 wt% SnO2-SiO2 nanocomposites to increasing EtOH concentrations in dry air.

Mentions: The sensing dynamics of the SnO2-SiO2 composites was different from that of the pure SnO2 nanoparticles (Figure 4, Figure 5 and Figure 6). To better investigate the effect of SiO2 cosynthesis on the sensing properties, all synthesis parameters were kept constant and only the Si-content was varied. Figure 7 shows the response to step-wise increases in EtOH concentration of a sensor made of as prepared 1.4 wt% SnO2-SiO2. The response and recovery times of these nanocomposites (Figure 7) were comparable to that of the pure SnO2 (Figure 5). Nevertheless, the magnitude of the sensor response was initially lower than that of the SnO2 nanoparticles (Figure 5) reaching about 37 at 50 ppm EtOH (Figure 7). This is in contrast to the smaller crystal size of these nanocomposites (Figure 3, triangles up) that should lead to higher sensitivity [5]. This is attributed to the sintering inhibition effect of the SiO2 that may have limited the growth of sintering neck between the main SnO2 grains.


Structural Stability and Performance of Noble Metal-Free SnO2-Based Gas Sensors.

Tricoli A - Biosensors (Basel) (2012)

Response of a gas sensor made of as prepared 1.4 wt% SnO2-SiO2 nanocomposites to increasing EtOH concentrations in dry air.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263576&req=5

biosensors-02-00221-f007: Response of a gas sensor made of as prepared 1.4 wt% SnO2-SiO2 nanocomposites to increasing EtOH concentrations in dry air.
Mentions: The sensing dynamics of the SnO2-SiO2 composites was different from that of the pure SnO2 nanoparticles (Figure 4, Figure 5 and Figure 6). To better investigate the effect of SiO2 cosynthesis on the sensing properties, all synthesis parameters were kept constant and only the Si-content was varied. Figure 7 shows the response to step-wise increases in EtOH concentration of a sensor made of as prepared 1.4 wt% SnO2-SiO2. The response and recovery times of these nanocomposites (Figure 7) were comparable to that of the pure SnO2 (Figure 5). Nevertheless, the magnitude of the sensor response was initially lower than that of the SnO2 nanoparticles (Figure 5) reaching about 37 at 50 ppm EtOH (Figure 7). This is in contrast to the smaller crystal size of these nanocomposites (Figure 3, triangles up) that should lead to higher sensitivity [5]. This is attributed to the sintering inhibition effect of the SiO2 that may have limited the growth of sintering neck between the main SnO2 grains.

Bottom Line: The effect of crystal growth during operation (TO = 320 °C) on the sensor response to ethanol has been reported, revealing possible long-term destabilization mechanisms.In particular, crystal growth and sintering-neck formation were discussed with respect to their potential to change the sensor response and calibration.Furthermore, the effect of SiO2 cosynthesis on the cross-sensitivity to humidity of these noble metal-free SnO2-based gas sensors was assessed.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical and Process Engineering, ETH Zurich, CH-8092 Zurich, Switzerland. atricoli@ethz.ch.

ABSTRACT
The structural stability of pure SnO2 nanoparticles and highly sensitive SnO2-SiO2 nanocomposites (0-15 SiO2 wt%) has been investigated for conditions relevant to their utilization as chemoresistive gas sensors. Thermal stabilization by SiO2 co-synthesis has been investigated at up to 600 °C determining regimes of crystal size stability as a function of SiO2-content. For operation up to 400 °C, thermally stable crystal sizes of ca. 24 and 11 nm were identified for SnO2 nanoparticles and 1.4 wt% SnO2-SiO2 nanocomposites, respectively. The effect of crystal growth during operation (TO = 320 °C) on the sensor response to ethanol has been reported, revealing possible long-term destabilization mechanisms. In particular, crystal growth and sintering-neck formation were discussed with respect to their potential to change the sensor response and calibration. Furthermore, the effect of SiO2 cosynthesis on the cross-sensitivity to humidity of these noble metal-free SnO2-based gas sensors was assessed.

No MeSH data available.