Recent progress in nitrates and nitrites sensor with graphene-based nanocomposites as electrocatalysts

Nutrients based on nitrogen elements such as nitrite and nitrate have long been served as food preservatives in the food industry, as fertilizer in agriculture, and as color formers and rust inhibitors in the chemical industry. Due to the extensive nitrite and nitrate usage, the leakage or pollution discharge resulted in a large amount wasted in water sources and soil. As they are highly toxic inorganic pollutant, excess consumption and nitrite exposure can trigger several diseases and damage human health. As a consequence, an urgent need to develop a particular device for detecting and monitoring the presence of nitrite, specifically to measure drinking water quality and control remediation procedures. Owing to the merits of graphene, including broad theoretical surface area, high conductivity at room temperature, and a wider electrochemical window, graphene now serves as an excellent host material for anchoring nanomaterials to enhance the performance of electrochemical applications. There has been rapid progress in developing nitrite and nitrate sensors based on an electrochemical approach with the assistance of graphene-based nanocomposite material as the electrocatalysts. The electrically conductive graphene has high surface areas that allow the deposition of high-density analyte molecules, facilitating better selectivity and high sensitivity compared to other materials. The present review provides an overview on the recent development of electrochemical sensors for detecting nitrates and nitrites using graphene-based nanocomposites as electrocatalysts based on selective reports.