Fundamental Basis for Distinctive Sensing of H2 in Humid Environment

Abstract

Accurate sensing of trace amount of hydrogen without interference from environment is highly desirable in timely detection of possible leakage when using hydrogen as a clean energy source. Humidity in air is usually considered as the main challenge to the performance of room temperature hydrogen sensors. In this work, we have demonstrated distinctive sensing of H2 in humid environment at room temperature, using (002) oriented TiO2 thin film as active sensing material. Through first‐principle calculations in the framework of density functional theory, we have clarified the interaction between H2O and rutile TiO2 (002) surface. It was found that H2O can be easily split into –H and –OH with a negligible activation energy below 0.07 eV on the TiO2 (002) surface. Catalytic splitting of water has rather little effect on the height of Schottky barrier between Pt and the TiO2 (002) surface, thus resulting in ignorable impact on hydrogen sensing property. The (002) oriented TiO2 thin film hydrogen sensor could be utilized in various humid environment at room temperature.