Ultrasensitive electrochemical detection of dopamine using an engineered 1D/2D MoO3/g-C3N4 nanohybrid

Abstract

This study explores the potential of nanocomposites of one-dimensional (1D) molybdenum trioxide (MoO₃) with two-dimensional (2D) graphitic carbon nitride (g-C₃N₄) for electrochemical detection of dopamine (DA). The nanocomposites with varying weight ratios of MoO₃ and g-C₃N₄ were synthesized via a facile wet chemical method and were systematically characterized using the PXRD, FTIR, UV-vis, FESEM, TEM, XPS and CV techniques. The maximum current responsiveness with least resistance was attained in electrochemical studies involving cyclic voltammetry (CV) and impendence measurements at a particular 2 : 1 MoO₃ and g-C₃N₄ weight ratio (M2G1). CV studies were used to examine the redox characteristics of DA, from which the linear and sensing ranges were found to be between 10 μM and 100 μM, with a limit of detection (LOD) of ∼1.40 μM. Using the differential pulse voltammetric (DPV) approach, DA sensing was achieved in the sensing range of 0.05 μM to 0.50 μM with an LOD of ∼64 nM. The amperometric sensing approach at a constant potential of 0.2 V demonstrated linear and sensing ranges of DA from 2 μM to 8 μM, and the LOD was found to be ∼0.4 μM. The response time for the amperometric sensing was less than two seconds. These findings demonstrate that the M2G1 nanocomposite is a highly sensitive electrocatalyst for detecting DA using different electrochemical techniques like CV, DPV, and amperometry, and it would be a perfect choice for neurotransmitter sensing applications.