Electrochemical Performance of a Non-Enzymatic Sensor Based on Sustainable Silica-Modified Carboxymethyl Cellulose/Pine Resin/Iron Oxide Nanoparticles

Abstract

In this study, novel organic–inorganic hybrid silica (SiO2)-modified carboxymethyl cellulose (CMC)/pine resin (PR)/iron oxide nanoparticles (Fe3O4/α-Fe2O3 NPs) were synthesized using a sustainable sonochemical approach. The surface and chemical properties of the SiO2-modified CMC/PR/Fe3O4/α-Fe2O3 NPs were characterized, and their potential as active materials for non-enzymatic electrochemical sensing was demonstrated. Morphological analysis revealed that the NPs possessed a spheroidal structure with particle sizes below 25 nm, providing a large active surface area favorable for electrochemical reactions. The sensor exhibited linear response behavior toward glucose and other carbohydrates within a concentration range of 12–64 mM. Notably, the single-layer sensor configuration demonstrated higher sensitivity (710 μA mM􀀀 1 cm􀀀 2) and a lower limit of detection (LOD) (1.1 mM) and limit of quantitation (LOQ) (3.67) mM for glucose compared to the double-layer sensor, indicating that increased film thickness adversely affects sensor performance due to enhanced electron diffusion resistance. Fe3O4/α-Fe2O3 NPs centers controlled the sensing mechanism, Si increased film uniformity and charge transport, PR facilitated electron transfer, and CMC offered electrode stability. Overall, the results demonstrate that the SiO2-modified CMC/PR/Fe3O4/α-Fe2O3 hybrid nanomaterials offer tunable structural and electronic properties, making them promising candidates for semiconductor-based electrochemical sensing applications.