Fabrication of p-Type Co3O4 Nanofiber Sensors for Ultra-Low H2S Gas Detection at Low Temperature

Abstract

In the current work, we report the on-chip fabrication of a low-temperature H2S sensor based on p-type Co3O4 nanofibers (NFs) using the electrospinning method. The FESEM images show the typical spider-net like morphologies of synthesized Co3O4 NFs with an average diameter of 90 nm formed on the comb-like electrodes. The EDX data indicate the presence of Co and O elements in the NFs. The XRD analysis results confirm the formation of single-phase cubic spinel nanocrystalline structures (Fd3 m) for the synthesized Co3O4 NFs. The Raman results are in agreement with the XRD data through the presence of five typical vibration modes of the nanocrystalline Co3O4. The gas sensing properties of the fabricated Co3O4 NF sensors are tested to 1 ppm H2S within a temperature range of 150 °C to 450 °C. The results indicate a highest sensor response to 1 ppm H2S with the gas response of aproximately 2.1 times and the gas response/recovery times of 75 s/258 s at a low temperature of 250 °C. The fabricated sensor also demonstrates good selectivity and a low detection limit of 18 ppb. The overall results suggest a simple and effective fabrication process for the p-type Co3O4 NF sensor for practical applications in detecting H2S gas at low temperature.