Carbon nanotubes/lithium ferrite nanocomposites: magnetic and electrochemical optimization for enhanced H₂O₂ sensing

Hydrogen peroxide (H2O2) is a ubiquitous molecule in biological systems, but at elevated concentrations, it exhibits cytotoxicity, necessitating precise monitoring for both biomedical and analytical applications. In this work, we report a cost-effective strategy for synthesizing carbon nanotube/lithium ferrite (CNTs/LFO) nanocomposites with different LFO doping levels (0.5%, 1%, and 2%) for non-enzymatic H2O2 sensing. The nanocomposites were fabricated via a citrate-gel auto-combustion route, yielding uniformly dispersed structures. X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) confirmed the presence of a crystalline ferrite phase with nanoplate particles averaging ∼50 nm. Vibrating sample magnetometry (VSM) revealed a maximum saturation magnetization of 25 emu g-1 for the 2% LFO composition. Electrochemical characterization using cyclic voltammetry (CV) demonstrated superior H2O2 sensing activity of CNTs/LFO compared to pure LFO, attributed to accelerated electron transfer at the CNTs-modified interface. The optimized electrode exhibited excellent stability, a low detection limit of 0.005 μM, and a wide linear response range of 0.1-500 μM. These results highlight CNTs/LFO nanocomposites as highly promising candidates for advanced H2O2 sensing and related electrochemical applications.