Role of reversible redox couples (Ni2+/Ni3+ and Fe2+/Fe3+) in selective H2O2 detection behaviour of two-pot synthesized NiFeP nanointerface: An enzyme-free voltammetric approach

Abstract

Probing H₂O₂ in drinking water is vital as it directly impacts the lives of aquatic animals and humans. Herein, we report an enzyme-free electrochemical voltammetric approach for selectively detecting H₂O₂ in drinking water employing NiFeP nanointerface for the first time. The NiFeP was synthesized via a two-pot synthesis by phosphorizing hydrothermally prepared NiFe Layered Double Hydroxides (LDH). Structural analysis revealed the disappearance of LDH-specific diffraction peaks ((0 0 3) and (0 0 6)) and the emergence of distinct NiFeP crystalline planes, confirming the successful structural conversion from NiFe-LDH to NiFeP. NiFeP nanointerface showed linear detection ranges of H₂O₂ (0.1–1 μM and 5–100 μM), with LODs of 0.027 μM and 1.58 μM, and sensitivities of 17.11 and 0.81 μA mM⁻¹ cm⁻², respectively. The enhanced electrochemical performance of the NiFeP system prevails in the interaction with H₂O_2, with substantial redox activity by reversible redox couples, compared to the NiFe LDH, where the redox couples (Ni²⁺/Ni³⁺ and Fe²⁺/Fe³⁺) are limited. This work demonstrates NiFeP as a redox-active nanointerface for highly selective enzyme-free H₂O₂ sensing, with recovery studies being carried out in drinking water, which validated its practical applicability in real-time environmental monitoring.