Nitrogen-rich core-shell structured particles consisting of carbonized zeolitic imidazolate frameworks and reduced graphene oxide for amperometric determination of hydrogen peroxide

Core-shell structured particles were prepared from carbonized zeolitic imidazolate frameworks (ZIFs) and reduced graphene oxide (rGO). The particles possess a nitrogen content of up to 10.6%. The loss of nitrogen from the ZIF is avoided by utilizing the reduction and agglomeration of graphene oxide with suitable size (>2 μm) during pyrolysis. The resulting carbonized ZIF@rGO particles were deposited on a glassy carbon electrode to give an amperometric sensor for H₂O₂, typically operated at a voltage of −0.4 V (vs. Ag/AgCl). The sensor has a wide detection range (from 5 × 10⁻⁶ to 2 × 10⁻² M), a 3.3 μM (S/N = 3) detection limit and a 0.272 μA·μM⁻¹·cm⁻² sensitivity, much higher than that of directly carbonized ZIFs. The sensor material was also deposited on a screen-printed electrode to explore the possibility of application. [Figure not available: see fulltext.].