Defect-Engineered Ni-Mof/NSP-Doped Biomass Carbon Heterostructure for Ultrasensitive Non-Enzymatic Hydrogen Peroxide Detection

Abstract

Non-enzymatic electrochemical detection of Hydrogen peroxide (H₂O₂) has gained significant attention due to its critical role in biomedical diagnostics, environmental monitoring, and food safety; however, existing systems predominantly rely on noble metals based materials for the sensor development, limiting their practical applicability. In this work, we report a defect-engineered Ni-MOF/NSP-doped orange peel-derived biomass carbon heterostructure as a sustainable and high-performance electrocatalyst for ultrasensitive H₂O₂. The composite was synthesized via a facile approach integrating Ni-based metal-organic framework growth with nitrogen, sulfur, and phosphorus co-doped activated carbon derived from orange peel waste. The synergistic heterointerface between Ni-MOF-derived active sites and defect-rich carbon significantly enhances charge transfer kinetics and catalytic activity. Electrochemical studies showed a low detection limit in the sub-micromolar range, high sensitivity exceeding conventional transition metal systems, and a wide linear detection range. The sensor demonstrates excellent selectivity against common interfering species and reliable performance in real sample analysis in artifcial urine and saliva sample. Furthermore, detailed electrokinetic investigations, including Tafel slope, scan rate analysis, and electrochemical impedance spectroscopy, provide insights into the intrinsic catalytic mechanism. The proposed system offers a cost-effective, scalable, and environmentally sustainable alternative to noble-metal-based sensors, advancing the development of next-generation electrochemical sensing platforms.