Green Synthesis of MnMoO4 Nanoparticles Using Salvia hispanica Seed Powder for Electrochemical Urea Sensing and Supercapacitor Applications

Objectives: Manganese molybdate (MnMoO4) nanoparticles were synthesised by using an eco-friendly combustion approach. These are used as sensor for detecting urea. Methods: MnMoO4 nanoparticles were synthesized by comburstion of a green precursor solution containing Salvia hispanica seed powder. Scanning Electron Microscopy (SEM) was used to characterise the morphology of the nanomaterails. Glassy Carbon Electrode (GCE) was modified by using developed MnMoO4 nanoparticles. Electrochemical studies were conducted such as Cyclic Voltammetry (CV), Linear Sweep Voltammetry (LSV), and Electrochemical Impedance Spectroscopy (EIS). Charge discharge tests were conducted using a nickel foam-coated electrode. Findings: SEM analysis revealed porous, aggregated nanoparticle structures. EIS studies shows that Rs and Rct values of 2.667 Ω and 1.628 Ω, respectively, indicating efficient charge transfer and successful electrode modification. In CV studies, the anodic peak current (Ipa) increased from 0.014 µA to 0.100 µA, confirming enhanced electrochemical activity, Linear relationship was found in LSV studies The NMO electrode has a specific capacity of 71.94 C·g-1 at a current density of 2.5 A·g-1. shows good energy storage application. Novelty: Existing studies on transition-metal molybdates mainly use hydrothermal or high-temperature chemical routes that are costly and environmentally taxing, with MnMoO4 mostly explored for supercapacitors rather than urea sensing. In contrast, this work presents a simple, low-cost green combustion method using Salvia hispanica seed powder, yielding MnMoO4 nanoparticles with excellent charge-transfer properties (Rs = 2.667 Ω, Rct = 1.628 Ω) and high sensitivity toward low-concentration urea (10 µM). This approach broadens the application of MnMoO4 while offering a greener and more efficient synthesis route. Keywords: MnMoO4, Sensor, Cyclic voltammetry, Charge and Discharge studies