Three-dimensional (3D) hierarchical structure engineering of AuNPs/Co(OH)2 nanocomposite on carbon cloth: An advanced and efficient electrode for highly sensitive and specific determination of nitrite

Excessive intake and emission of nitrite will cause serious harm to the ecosystem and human health. Herein, the AuNPs/Co(OH)2 nanocomposites with a unique three-dimensional (3D) hierarchical structure are designed and synthesized for the detection of nitrite. Wheatear-like cobalt hydroxide (Co(OH)2) is synthesized on carbon cloth (CC) by hydrothermal method. Flower bud-like gold nanoparticles (AuNPs) are electrodeposited on Co(OH)2. By integrating the common advantages of AuNPs and Co(OH)2 such as enlarged specific surface area, significantly increased active sites, high conductivity, and 3D hierarchical structure, the proposed AuNPs/Co(OH)2/CC electrode shows excellent nitrite sensing properties, with the linear range of 0.625–3387.5 μM, the limit of detection (LOD) of 0.1 μM, and high sensitivity of 2475.5 μA mM−1 cm−2. Moreover, the sensor can measure nitrite content in sausages with high recoveries, indicating its feasibility in practical application. This work guides the reasonable design of 3D hierarchical nanomaterials and the construction of high-performance sensing interfaces.