Nanozymes: Emerging Nanomaterials to Detect Toxic Ions

Since magnetic Fe3O4 nanoparticles were discovered to show intrinsic peroxidase-like catalytic activity in 2007, nanoscale materials with enzyme-mimicking characteristics (nanozymes) have attracted considerable interest from the academic and industrial communities. Unlike vulnerable natural enzymes that need complicated separation and purification processes at high cost, nanozymes with better robustness against harsh environments can be massively produced with lower cost. These merits have endowed them with promising applications in catalysis, sensing, biomedicine, and environmental engineering. Particularly, their catalytic properties can be easily tuned by foreign species like some ions, making it possible to employ them to design new methods for the determination of these species. In this book chapter, we aim at summarizing nanozymes used as emerging nanomaterials to detect toxic ions. Typically, detection of inorganic Hg2+, Ag+, arsenate/arsenite, Pb2+, [Cr2O7]2−, halide ions, phosphates and S-containing species based on the modulation of nanozyme activity is reviewed, and the underlying sensing mechanisms and strategies explored are comprehensively classified. Their opportunities and challenges in future toxic ion analysis for environmental monitoring are also discussed.