H2S-sensing properties of flame-synthesized RuO2-decorated WO3 nanoparticulate spin-coated films

Abstract

This work aimed to develop effective and reliable H2S gas sensors based on flame-synthesized RuO2-decorated WO3 spin-coated films. Inclusive material characterizations unveiled the decoration of 1–3 nm RuO2 nanoparticles on 10–25 nm WO3 nanoparticles with 0–1 wt% Ru. Sensing layers coated with 1–6 cycles were tested towards 0.25–10 ppm H2S at 200–400 °C under various humidity conditions (0–80 %RH). The sensors with four spin-coated layers and 0.2 wt% Ru presented a reproducibly optimum response of ∼71.0 with a fair response time of ∼ 15.1 s to 10 ppm H2S in dry ambient at 350 °C. Additionally, the optimal sensor exhibited high H2S selectivity with respect to CH3SH, CH3SCH3, C3H6O, C2H5OH, CH3OH, CH2O, C6H6, C8H10, NO2, NO, H2, CH4, CO2, C2H2, HCOOH, CH3COOH, and CH3CHOHCOOH. Furthermore, the sensors displayed decent repeatability and satisfactory medium-term stability of resistance and response. Therefore, flame-synthesized RuO2-loaded WO3 nanoparticles were promising for effective and practical H2S sensing.