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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.


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ED patterns of pure (a) SnO2 nanoparticles and (b) 1.4 wt% SnO2-SiO2 nanocomposites after 4 h sintering at 400 °C and corresponding transmission electron microscopy (TEM) images (c,d).
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biosensors-02-00221-f002: ED patterns of pure (a) SnO2 nanoparticles and (b) 1.4 wt% SnO2-SiO2 nanocomposites after 4 h sintering at 400 °C and corresponding transmission electron microscopy (TEM) images (c,d).

Mentions: Cosynthesis of SiO2 led already at very low content (1.4 wt%) to remarkable long-term thermal-stabilization of the small SnO2 nanoparticles. The average crystal size of these SnO2-SiO2 nanocomposites (Figure 1, circles) increased only from 9.5 to 10.5 nm with increasing sintering time from 0 to 24 h. The particles were mainly polyhedrical (Figure 2(c,d)) consisting of a crystalline SnO2 core and some dispersed SiO2 phase. At high SiO2 content, the SnO2 and SiO2 phase were segregated in crystalline and amorphous domains, respectively. This is in line with the reported thermal stabilization and performance maximization of SnO2- [7] and WO3-based [19] gas sensors by Si-doping. Here, it is shown that this noble metal-free approach to improve the performance of metal-oxide chemoresistive gas sensors offers also superior long-term structural stability.


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

Tricoli A - Biosensors (Basel) (2012)

ED patterns of pure (a) SnO2 nanoparticles and (b) 1.4 wt% SnO2-SiO2 nanocomposites after 4 h sintering at 400 °C and corresponding transmission electron microscopy (TEM) images (c,d).
© Copyright Policy
Related In: Results  -  Collection

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

biosensors-02-00221-f002: ED patterns of pure (a) SnO2 nanoparticles and (b) 1.4 wt% SnO2-SiO2 nanocomposites after 4 h sintering at 400 °C and corresponding transmission electron microscopy (TEM) images (c,d).
Mentions: Cosynthesis of SiO2 led already at very low content (1.4 wt%) to remarkable long-term thermal-stabilization of the small SnO2 nanoparticles. The average crystal size of these SnO2-SiO2 nanocomposites (Figure 1, circles) increased only from 9.5 to 10.5 nm with increasing sintering time from 0 to 24 h. The particles were mainly polyhedrical (Figure 2(c,d)) consisting of a crystalline SnO2 core and some dispersed SiO2 phase. At high SiO2 content, the SnO2 and SiO2 phase were segregated in crystalline and amorphous domains, respectively. This is in line with the reported thermal stabilization and performance maximization of SnO2- [7] and WO3-based [19] gas sensors by Si-doping. Here, it is shown that this noble metal-free approach to improve the performance of metal-oxide chemoresistive gas sensors offers also superior long-term structural stability.

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.


Related in: MedlinePlus