Amperometric sensor based on ZIF/g-CN/RGO heterojunction nanocomposite for hydrazine detection.

A dense  zeolitic imidazolate framework (ZIF) nanosheet is for the first time molded by reduced graphite oxide (RGO) and graphitic carbon nitride (g-CN) to fabricate an original 2D/2D/2D heterojunction (ZIF/g-CN/RGO nanohybrid), which is pipetted onto carbon cloth electrode (CCE) (ZIF/g-CN/RGO/CCE) as an electrochemical sensor. Profiting from the renowned synergistic and coupling effects, the resulting nanohybrid endows excellent electrocatalytic activity towards hydrazine. Amperometric detection reveals that the hybrid sensor possesses a low detection limit of 32 nM (S/N = 3) in a monitoring range of 0.0001 to 1.0386 mM, along with a high sensitivity 93.71 μA mM cm. Importantly, the minimum detection concentration of hydrazine in the actual sample is lower than the maximum allowable limit of the World Health Organization (WHO) and has high reproducibility (RSD = 4.82%). As expected, the high sensing capability  of ZIF/g-CN/RGO combines the advantages of abundant surface-active sites and high conductivity along with 2D interfaces between ZIF, g-CN, and RGO nanosheets. This study provides a promising to expand 2D-based ternary nanojunction as a bridge for promoting sensing performance.Graphical abstract.