Spindle-like Fe₃O₄/NiO/N-Doped Carbon Nanocomposites for High-Performance Nitrite and Hydrogen Peroxide Sensing

Considering the destructive effect of excess residues of nitrite (NO 2 – ) and hydrogen peroxide (H 2 O 2 ) in food, herein, we introduce a unique synthetic strategy to design and construct high-performance sensing heterostructure materials [spindle-like Fe 3 O 4 /NiO@N-doped carbon (Fe 3 O 4 /NiO@N–C)] using Fe-based metal–organic frameworks as self-sacrifice template and further evaluate its quantitative capabilities for NO 2 – and H 2 O 2 determination. Notably, the well-designed three-dimensional hierarchical hollow Fe 3 O 4 /NiO@N–C nanocomposites integrate the significant merits of hollow heterointerface structure and suitable electrocatalytic properties of different nanomaterials, which prompt the exposure of electroactive sites, the acceleration of electron/ion transfer rate, as well as the prolongation of structural robustness when unitized as electrocatalysts for NO 2 – oxidation and H 2 O 2 reduction. Accordingly, it achieved remarkable sensitivity (1040.3 ± 0.0078 and 615.7 μA mM –1 cm –2 ± 0.0056) and low limit of detection (LOD) (21 and 129 nM) at desirable working potential (0.85 and −0.45 V); meanwhile, their selectivity, durability, and repeatability are also deserved to be declaimed. More importantly, this realizes successful recovery analysis in pickled mustard with high reliability and excellent applicability. Such significative research could provide instructive advice for the reasonable design of other heterostructured metal oxide and further highlight their untapped potential in food analysis, as well as human health and ecosystems.