Novel amperometric carbon monoxide sensor based on multi-wall carbon nanotubes grafted with polydiphenylamine—Fabrication and performance

A novel amperometric sensor based on multi-wall carbon nanotubes (MWNT) grafted polydiphenylamine (PDPA), MWNT-g-PDPA, has been developed for the determination of carbon monoxide (CO). Cyclic voltammetry is used to fabricate the modified electrode and to demonstrate the electroactivity of MWNT-g-PDPA-ME toward gaseous CO. The MWNT-g-PDPA-ME exhibits high sensitivity for oxidation of CO in a 0.5 M HClO4 solution. Chronoamperometry is carried to determine the working range of CO at MWNT-g-PDPA-ME. The dependence of the response current on CO concentration is explored under optimal conditions and an excellent linear concentration range between 10 and 200 ppm (correlation coefficient r = 0.9941) with a substantially low detection limit of 0.01 ppm is obtained. Further, the response and recovery transients of CO gas at MWNT-g-PDPA-ME are determined.