Electrochemical treatment of carbon nanofibers: mild conditions and enhancing the NO2 sensing behavior

Room-temperature gas sensors for the detection of NO 2 and NH 3 based on electrochemically treated carbon nanofibers were investigated. Electrochemical treatment of the carbon nanofibers was carried out in a sulfuric acid solution at currents ranging from 0.5 to 2.5 A, with the highest level of functionalization achieved at 2.0 A. The carbon nanomaterials were characterized using transmission electron microscopy, low-temperature nitrogen adsorption, X-ray diffraction, Raman spectroscopy, and Fourier transform infrared spectroscopy. Chemiresistive gas sensors were fabricated using the electrochemically treated carbon nanofibers for NO 2 detection at room temperature. Sensors based on carbon nanofibers treated at 2.0 A exhibited a response of 4.8% to 2 ppm NO 2 (25 ± 1 °C). New approaches for the use of electrochemically treated CNFs in the development of all-carbon sensing materials are proposed. The response was increased to 14.7% (at 2 ppm NO 2 ) by using a composite based on treated carbon nanofibers and multi-walled carbon nanotubes as the active material, along with improvements in recovery and response time.