NASICON-type Na3Fe2(PO4)3 material for an excellent room temperature CO sensor

Here we report an ultra-sensitive room temperature carbon monoxide (CO) gas sensor based on Na3Fe2(PO4)3 (NFP, NASICON-type monoclinic structure material) for the first time. The NFP powder with a plate-like morphology was synthesized using a simple and economical sol–gel technique. The sensor device was fabricated by a thick film coated on copper (Cu) interdigitated electrodes. The selectivity of the prepared material was studied by exposing it to different gases and investigating the performance for each gas. The sensor displayed excellent selective detection of CO gas at room temperature. The sensor showed a rapid response of ∼417.58 in just ∼14 s when exposed to 500 ppm CO gas and recovered to the baseline in just ∼3 s after the removal of CO gas. The measured signal is more than 100 times the blank signal and the proposed sensor exhibits ∼(5–500) times higher response than the conventional resistive type sensor. The sensor demonstrated excellent reproducibility (cycling stability) towards numerous cycles of exposure to CO gas at room temperature. The favorable gas-sensing properties of the NASICON-type NFP fortify its potential utilization as a next-generation CO gas-sensing material that employs only cost-effective and earth-abundant elements.