MXene electrochemical phosphate sensors

Rapid and accurate detection of molecular species with a high degree of selectivity and sensitivity constitutes the ultimate goal of designing sensors for various applications, from studying nutrients in soil-water systems to assessing physiological conditions in human health. With recent progress, two-dimensional (2D) transition metal carbides/nitrides have shown great potential for applications such as energy storage and electromagnetic interference shielding. However, the fundamental electrochemical studies and subsequent applications of MXenes for molecular sensing are still in their infancy. Here, we use 2D sheets of titanium carbide (Ti₃C₂T_x) MXene for electrochemical detection of phosphate, a key molecule for sustainability of life on earth, and major contributor to environmental pollution. Ti₃C₂T_x MXene sensors were demonstrated to be highly selective towards phosphate with a sensing range from 1 µM to 350 µM and a limit of detection (LOD) of 1.31 µM. This work lays the foundation for molecular sensing using Ti₃C₂T_x MXene in complex environments.