A low power catalytic combustion gas sensor based on a suspended membrane microhotplate

A microhotplate based catalytic combustion gas sensor with low power consumption employing Pd-Pt/ γ-Al₂O₃ is presented in this paper. The microhotplate was fabricated on a silicon substrate by micromachining process. And the sensitive material Pd-Pt and compensation material γ-Al₂O₃ were prepared by sol-gel process. This sensor has been tested under constant working voltage to methane gas and achieved good performance. With the increasing of working voltage, both the output signal and power consumption of the sensor increased. The ratio of the sensitivity to power consumption was considered as an optimizing factor for selecting a rational working voltage. The sensor output signal showed a fairly linear relationship to the methane gas concentration. It achieved a sensitivity of 2mV/%CH₄ to 50% LEL methane gas at a low power of 52mW.