Ti₃C₂T_x MXene-Based Electrochemical Sensors for Phosphate Detection

The recent surge of the Internet of Things (IoT) has left an indelible mark on the global sensor market, spurring further research in a similar direction. At the heart of any sensor lies the sensing material and its intrinsic characteristics that define the key sensor metrics such as selectivity, sensitivity, limit of detection and dynamic range. Electrochemical sensors, known best for their dominance in rapid detection, cost efficiency and accuracy, are no exception to this paradigm. To date, many nanomaterials, including two-dimensional (2D) graphene, have been discovered and used as electrochemical sensing platforms for various biomedical and environmental applications. 2D transition metal carbides/nitrides (also known as <i>MXenes</i>), with their unique structure and presence of transition metals, have demonstrated large surface to volume ratio, high electrical conductivity, ease of functionalization and solution processibility. However, their electrochemistry and electrochemical stability have received limited exploration. Recently, there has been a growing focus on delving deeper into these aspects. Phosphate ions are intriguing molecules with significant relevance in environmental and biomedical applications. Understanding its detection in a solution environment using <i>MXene</i> as a sensing electrode will unveil <i>MXene</i>’s outstanding properties for unique applications as a phosphate sensor. Herein, we studied the performance of Ti₃C₂T_x <i>MXene</i> on a standard glassy carbon electrode in detecting phosphate ions in an electrochemical setup in the presence of molybdenum in an acidic media. The quality of Ti₃C₂T_x <i>MXene</i> was extensively characterized prior to serving as the sensing material in the electrochemical system. The proposed method demonstrated high selectivity in the presence of common interfering ions. The Ti₃C₂T_x <i>MXene</i> sensor also exhibited low detection limit and high sensitivity towards phosphate ions along with a large linear detection range with reliable performance. This research lays the groundwork for the advancement of Ti₃C₂T_x <i>MXene</i>-based phosphate sensors, promising future applications in environmental monitoring and sensing.