Micro Hydrogen Gas Sensor Based on Bi-Te Film Couples and Pt/ACC

TE (Thermoelectric) materials have been widely used in clean energy system as low-power generator and Peliter cooler, due to its salient features of being compact, light-weighted, noiseless in operation, highly reliable, and environment friendly. Recently, another application has been explored on TE materials as gas sensors based on Seebeck effect and exothermic reaction of hydrogen oxidation on catalyst. In this paper, a TE hydrogen gas sensor with a simple structure, low energy consumption and a high sensitivity was reported. Bi-Te (bismuth telluride) with a high Seebeck coefficient at room-temperature was deposited onto thin glass substrates by RF magnetron sputtering technology. Four pairs of PN film couples were connected in series to improve the output voltage. Pt/ ACC (Activated Carbon Fiber Cloth) was mounted at the joint of PN couples, acting as catalyst so as to accelerate the oxidation of hydrogen. The influences of reduction temperature and Pt content on the generated temperature difference were investigated. The voltage output and selectivity to combustible gas mixture were measured. Experimental results showed that when exposed to 3vol% H2/ air, as-prepared sensor gave out a high output signal of 33.1mV, and the response time was about 50s with recovery time of 50s.