Confinement preparation of Au nanoparticles embedded in ZIF-67-derived N-doped porous carbon for high-performance detection of hydrazine in liquid/gas phase

•Au nanoparticles-embedded N-doped porous carbon anchored on reduced graphene oxide.•A confinement preparation process and an increased porosity process have been used.•Such nanosheet was used for detection of hydrazine in liquid phase and gas phase.•The linear detection range is from 0.05 to 1.00 μM, the detection limit is 9.6 nM.•The gas sensor shows the detection limit of 1.8 ppm with fast response/recovery.