Effects of Surface Modification of Noble-metal Electrodes with Au on the H_2-sensing Properties of Diode-type Gas Sensors

摘要

Diode-type TiO_2 film gas sensors equipped with noble-metal (Pd or Pt) electrodes (M/TiO_2, M = Pd or Pt) have been fabricated, and the effects of surface modification of the electrodes with Au on their H_2-sensing properties have been investigated at 250°C in both air and No under dry and wet atmospheres. H_2 response of M/TiO_2 sensors in dry N_2 was much larger than that in dry air, but the surface modification of the Pd or Pt electrode with Au (Au/Pd or Au/Pt) improved the H_2 response, especially in dry air. In addition, the sensor with the Au/Pt electrode showed large and O_2-independent H_2 response under wet atmosphere.