Fast and Continuous Synthesis of NiCo₂(OH)_x Nanosheet Precursor in Preparation of NiCo₂O₄ Nanorod Networks for Glucose Sensing

It is still a challenge to prepare nanomaterials with desired structure and properties on a large scale. This research aims to develop a method for synthesis of NiCo 2 O 4 nanorod networks for their potential application in glucose sensors. NiCo 2 (OH) x nanosheets are prepared continuously by using a static mixer as a tubular reactor. The formation of NiCo 2 (OH) x nanosheets is completed within 5 s, resulting in a high yield of 0.1 g/min. The NiCo 2 (OH) x nanosheets convert to NiCo 2 O 4 polycrystalline nanorod networks through sintering at 450 °C. The NiCo 2 O 4 nanorods have abundant Ni(II)/Ni(III) and Co(II)/Co(III) active sites, which enhance the electrochemical performance and have great application in glucose sensors. The NiCo 2 O 4 -based glucose sensors have a sensitivity of 1442 μA mM –1 cm –2, a low limit of detection of 0.6 μM, and a wide linear range of 1.8 μM to 2 mM at an applied potential of 0.65 V (vs Hg/HgO). The sensors also exhibit excellent selectivity against common interferents (ascorbic acid, dopamine, etc.) and retained 85% activity after 30 days. The glucose sensors show high reliability in monitoring the real human serum samples.