H2S sensing mechanism of SnO2-CuWO4 operated under pulsed temperature modulation

• Published in: Sensors and actuators. B, Chemical Chemical, 2018-04, Vol.259, p.258-268
• Main Authors: Simion, Cristian Eugen, Somacescu, Simona, Teodorescu, Valentin Serban, Osiceanu, Petre, Stanoiu, Adelina
• Format: Article
• Language: English
• Subjects: H2S sensing mechanism under infield conditions; Pulsed temperature mode; Simultaneous electrical and photoacoustic measurements; SnO2-CuWO4
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2017.12.027

[Display omitted] •SnO2-CuWO4 materials were synthesized by a versatile chemical synthesis route.•TEM investigations revealed the existence of SnO2 and Cu1 + xWO4 crystalline phases.•XPS spectroscopy emphasized the increased affinity of SWC_800 towards OH groups.•Pulsed Temperature Modulation reveals the sensing properties of SnO2-CuWO4.•Sensitive selectivity to H2S and the sensing mechanism of SnO2-CuWO4 has been addressed under infield conditions. This paper reports the sensing mechanism of SnO2-CuWO4 mixed oxides towards H2S detection revealed through Pulsed Temperature Mode (PTM). After thick film deposition onto commercial substrates, the final annealing temperature enhances the material reliability through the changes occurred during the experimental conditions. PTM approach represents a tradeoff in terms of sensing mechanism versus sensing performance, in order to get insights about the fundamental aspects. The measurements have been done under dynamic gas flow conditions, in the presence of 50% relative humidity (RH). The gas sensors based on SnO2-CuWO4 exhibit sensor signals higher than 100 to 10 ppm H2S, low cross-sensitivity to common gaseous interfering agents (CO, CH4, NH3, SO2), average selective sensitivity of 8.64 towards the main interfering NO2 gas, moderate response (4 min)/recovery (5 min) transients and power consumption. In order to emphasize the role of moisture towards H2S detection mechanism, the photoacoustic spectroscopic insights were correlated with Transmission Electron Microscopy and X-ray Photoelectron Spectroscopy results. Such approach has shown promising aspects towards further operational sensitive devices.