We investigated the H2 sensing properties of a catalytic combustion-type hydrogen sensor using a BaTiO3-based positive temperature coefficient (PTC) thermistor as a transducer. In this sensor, catalytic combustion of H2 on Pt electrodes or a catalyst layer induces a remarkable change in the electric resistance as a sensor signal when the operating temperature is set near the Curie temperature of BaTiO3 (120 °C). However, the sensor response to H2 is relatively low at lower H2 concentrations because of lower combustion efficiency near 120 °C. In this study, Ba0.9(Bi0.5Na 0.5)0.1Ti0.999Nb0.001O3 (BNN-BT) with a higher Curie temperature (146 °C) was used as a transducer to increase the operating temperature and thus improve the sensor response. The sensor using BNN-BT and a Pt/SiO2 combustion catalyst showed improved sensor responses particularly at lower H2 concentrations. It also showed good response and recovery behaviors in response to 100-1000 ppm H 2 in air.
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics
- Electrical and Electronic Engineering