An enzyme-free electrochemical sensor based on reduced graphene oxide/Co3O4 nanospindle composite for sensitive detection of nitrite

•Facile synthesis of Co3O4 nanospindles/RGO composite.•The low detection limit for nitrite sensing was identified as 0.14μM.•Detection of wide range (1–380μM) of nitrite concentrations.•High stability and reproducibility of the composite electrode.•Excellent anti-interference capacity towards various common ions. Cobalt oxide (Co3O4) nanospindles-decorated reduced graphene oxide (RGO) composite is prepared via thermal decomposition of a three-dimensional coordination complex precursor, cobalt benzoate dihydrazinate, at 200°C. Transmission electron microscopy reveals that Co3O4 nanospindles with an average particle size of