Ultrafast response/recovery and high sensitivity of a hydrogen gas sensor at room temperature based on electrochemically deposited Sb2Te3/polystyrene composite film

Abstract

A novel thermochemical hydrogen (TCH) sensor was fabricated from a thermoelectric (TE) film and platinum nanoparticle (Pt-NP)-decorated graphene catalyst applied onto the TE film, and its hydrogen (H2) sensing performance was systemically investigated. Two types of films comprising stoichiometric antimony telluride (Sb2Te3) and a Sb2Te3/polystyrene (PS) composite were synthesized by cost-effective electrodeposition on a silicon (Si) substrate. The resulting Sb2Te3/PS composite film played an important role in improving the H2 sensing signal. Specifically, the sensing signal of the optimized TCH sensor based on the Sb2Te3/PS composite film was 29.3 times higher than that of the Sb2Te3-film-based TCH sensor under 2.5 vol% H2/air at room temperature (RT). This phenomenon can be explained by the lower thermal conductivity of the Sb2Te3/PS composite film, increasing the temperature difference relative to that of the Sb2Te3 film. The R-squared correlation coefficient (R2) of the composite-film-based TCH sensor with a range of 400 ppm to 7 vol% H2/air was 0.9916. The best response time and recovery time of the composite-film-based sensor were 4 s and 3 s at 3 vol% H2/air, respectively. Our results prove that this sensor provides a wide detection range, short response/recovery time, and high sensitivity at RT, which shows its potential for use as a commercial H2 sensor for infrastructure applications.