Highly sensitive detection of nitrite at a novel electrochemical sensor based on mutually stabilized Pt nanoclusters doped CoO nanohybrid

•A low-cost and stable Pt nanocluster doped nanoporous CoO was prepared facilely.•The electrocatalytic activity of the nanohybrid for nitrite oxidation was evaluated.•The Pt nanoclusters without aggregation enhanced the performances of nitrite sensor.•The electrochemical sensor detected nitrite in real samples with acceptable results. A novel, low-cost and mutually stable Pt nanocluster doped nanoporous CoO (Pt/CoO) has been successfully designed and synthesized by facilely dealloying Al85Co14Pt1 ternary alloy in alkaline solution. Electronic microscope images demonstrated the Pt nanoclusters are doped inside of the CoO crystal structure and they were mutually stabilized with each other, resulting in a high electrocatalytical activity even if the content of Pt was extremely low. A new electrochemical sensor was then constructed by modifying the Pt/CoO nanohybrid on a glassy carbon electrode, which enabled amperometric sensing of nitrite with wide linear ranges of 0.2 μM-3.67 mM and 3.67–23.7 mM, high sensitivities of 901.4 and 408.5 μA mM−1 cm-2 as well as a low detection limit of 0.067 μM (S/N = 3). Furthermore, the sensor showed good selectivity, stability and reproducibility towards nitrite detection. The feasibility of the electrochemical sensor was proved by successful detection of nitrite in real samples.