Recent advances in g-C₃N₄ based sustainable sensors for toxic mercury (Hg²⁺) detection

Mercury (Hg²⁺) is an exceedingly toxic environmental pollutant, and its prolonged exposure poses a significant risk to human health and the ecosystem. The serious health risks associated with mercury exposure have been studied via regular monitoring of mercury in aquatic environments using different methods. Although the advantages of traditional methods are undeniable, they are often associated with some limitations. In response to these limitations, in recent years, nanomaterial-based sensing platforms have been developed as promising alternatives. Among the diverse nanomaterials, graphitic carbon nitride (g-C₃N₄) has captured substantial attention as an advanced sensing material owing to its distinctive band structure, excellent chemical and thermal stability, and versatile surface chemistry. The purpose of this review article is to provide the scientific community, researchers and scholars with a thorough overview of recent advances in g-C₃N₄-centered materials and their sensing mechanisms toward Hg²⁺ detection. It encompasses a diverse range, including g-C₃N₄ NPs, g-C₃N₄@metal nanoparticles, g-C₃N₄@metal oxides, g-C₃N₄@quantum dots, and g-C₃N₄@polymeric composites, elucidating structure-property relationships, sensing mechanisms, analytical performance, and real-sample applicability.