Novel (CH6N3+, NH3+)-functionalized and nitrogen doped Co3O4 thin film electrochemical sensor for nanomolar detection of nitrite in neutral pH

Abstract

The present work provides a soft chemical route for simultaneous nitrogen doping and (CH6N3+, NH3+)-functionalization of pre-deposited Co3O4 thin film. The Co3O4 thin film was prepared by metal-organic decomposition (MOD) on fluorine-doped tin oxide (FTO) substrate and hydrothermally treated in the presence of amino acid, L-Arginine. The L-Arginine-treated Co3O4 thin film (L-Arginine/Co3O4/FTO) was used for the electrochemical detection of nitrite under neutral pH condition. Various physical (i.e. XRD, XPS, SEM, and Raman spectroscopy) and electrochemical characterization (i.e. CV, CA, EIS, and Tafel slope) was conducted to elucidate the role and effect of L-Arginine on Co3O4 film and determine the sensor performance characteristics. L-Arginine/Co3O4/FTO electrode exhibited a low limit of detection of 1.95 nM, an ultrafast response time of <2 s, and a wide linear range of up to 16 mM in neutral pH. The sensor was nitrite selective in the presence of common interferants and showed chemical stability and reproducibility. The practical application of the proposed sensor was demonstrated using real samples for nitrite detection.