Thermoelectric hydrogen sensor working at room temperature prepared by bismuth–telluride P–N couples and Pt/γ-Al2O3

A hydrogen sensor working at room temperature with high sensitivity, good selectivity and simple structure was presented in this paper. Four couples of P- and N-type bismuth–telluride films were connected in series to serve as the feedback part of the hydrogen sensor with a high Seebeck coefficient of 1.1 mV/K. A platinum catalyst was deposited on γ-Al2O3 acting as a sensitive part. Linear relationships between the output voltage and the hydrogen concentration as well as the flow rate were found when the hydrogen concentration was higher than 0.5 vol.%. As for the 3 vol.% H2/Air gas with a 100 ml/min flow rate at room temperature, the response and recovery times were about 30 and 55 s, respectively, and the error of repeatability was less than 0.3%.