Investigation of a new In2O3-based selective H2 gas sensor with low power consumption

The nanometer-size In2O3 was synthesized via a reverse microemulsion. A new catalytic combustion-type In2O3-based H2 gas sensor was developed based on the technology for fabricating the direct-heating-type sensor and a surface-modifying process. A dense SiO2 layer near the surface of the sensor was formed by chemical vapor deposition (CVD) of hexamethyldisiloxane (HMDS). The SiO2 layer, which acted as a molecular sieve, reduced the penetration of large molecular, such as C2H5OH, CH4, i-C4H10, into the sensing layer, resulting in the improvement of selectivity to H2. The sensitive properties and the working mechanism of the sensor were presented. The In2O3 nanoparticles prepared by microemulsion were characterized by transmission electron microscopy and X-ray diffraction.