Green synthesis of chitosan-templated MgO nanorods for enhanced hydrazine electrochemical oxidation

Abstract

This work details an eco-friendly green synthesis of magnesium oxide (MgO) nanoparticles using chitosan as a template. These nanoparticles are designed as a high-performance, noble metal-free electrocatalyst for hydrazine oxidation. The synthesis process employs a sacrificial template technique during calcination, yielding a distinctive one-dimensional (1D) nanorod structure. Although some regions exhibit partial agglomeration, the mesoporous, defect-rich architecture significantly increases the availability of Mg²⁺ active sites and promotes faster interfacial charge transfer. The MgO-modified electrode exhibits a high peak anodic current density of 37.63 mA/cm² at 0.80 V (vs Ag/AgCl) in a 1.0 M KOH electrolyte containing 0.5 M hydrazine. This electrocatalytic performance is highly competitive when compared to reported Cu-NPs@f-MWCNTs composites. It is evidenced by a lower onset potential of +0.389 V and a Tafel slope of 76.90 mV/dec. Furthermore, it competes with numerous benchmarks established for transition metal oxide–based hydrazine-oxidation catalysts. Kinetic investigations reveal a diffusion-controlled mechanism characterized by a high catalytic turnover rate. By integrating an environmentally sustainable, cost-effective synthesis method with notable electrochemical performance, these chitosan-templated MgO nanorods offer a consistent and economical alternative to noble-metal catalysts. These findings substantiate their potential for application in high-efficiency direct hydrazine fuel cells (DHFCs) and sophisticated electrochemical sensors for environmental monitoring.