Electrochemical and Photoelectrochemical Bimodal Sensor Based on Copper Modified g-C3N4 for Nitrate Detection

Abstract

Nitrates (NO₃^-) are crucial in agricultural practices and the food industry, but their excessive presence in water can lead to adverse health effects. Their leaching into water sources necessitates regular monitoring. This study introduces a novel bimodal electrochemical (EC)/photoelectrochemical (PEC) sensor, utilizing copper-modified graphitic carbon nitride (Cu/g-C₃N₄), designed for precise nitrate determination. The structural morphology and chemical composition of the Cu/g-C₃N₄ nanocomposite were meticulously examined using Transmission Electron Microscopy (TEM) and Fourier-transform infrared spectroscopy (FTIR). The optimization of copper loading in g-C₃N₄ was conducted, and the electrochemical behavior and light irradiation interaction of various Cu/g-C₃N₄ nanocomposites were systematically studied. The investigation revealed that 20 % Cu/g-C₃N₄ represented the optimal doping ratio, establishing the most promising candidate for NO₃^-. Nitrates were consistently measured using both EC and PEC techniques, yielding Limits of Detection (LoD) of 3.75 and 9.60 ppm, respectively. The sensor‘s robust performance was further demonstrated in the presence of possible interferents. The proposed sensors were also successfully used to detect NO₃^- in commercial water. This bimodal sensor presents a promising approach for accurate nitrate determination, attesting to its potential for effective cross-validation.