Pt Loading of Phosphorus-Doped Carbon Nanotube Aerogels in Fuel Cell-Type Gas Sensors for Ultrasensitive H2 Detection.

ABSTRACT

A phosphorus-doped carbon nanotube (CNT) aerogel as the support material was loaded with Pt nanoparticles in fuel cell-type gas sensors for ultrasensitive H2 detection. The high surface area of the CNT scaffold is favorable to providing abundant active sites, and the high electrical conductivity facilitates the transport of carriers generated by electrochemical reactions. In addition, the CNT aerogel was doped with phosphorus (P) to further enhance the conductivity and electrochemical catalytic activity. As a result, the fuel cell-type gas sensor using the Pt/CNT aerogel doped with the optimal P content as the sensing material shows considerable performance for H2 detection at room temperature. The sensor exhibits an ultrahigh response of -921.9 µA to 15,000 ppm of H2. The sensitivity is -0.063 µA/ppm, which is 21 times higher than that of the conventional Pt/CF counterpart. The sensor also exhibits excellent repeatability and humidity resistance, as well as fast response/recovery; the response/recovery times are 31 and 4 s to 3000 ppm of H2, respectively. The modulation of the structure and catalytic properties of the support material is responsible for the improvement of the sensor performance, thus providing a feasible solution for optimizing the performance of fuel cell-type gas sensors.