Ti₃C₂T_x/Au NPs/PPy ternary heterostructure-based intra-capacitive self-powered sensor for DEHP detection

Phthalate esters, particularly di(2-ethylhexyl) phthalate (DEHP), are widely used plasticizers found in various consumer products, posing significant environmental and health risks due to their endocrine-disrupting effects. In this study, a novel enzyme-free intra-capacitive biofuel cell self-powered sensor (ICBFC-SPS) was developed. The ICBFC-SPS integrated a ternary heterostructure-based capacitive anode and a cathode with a sensing interface into a single-chamber electrolytic cell. The ternary heterostructure based on Ti₃C₂T_x MXene with ultra-small Au NPs and polypyrrole (PPy) NPs was prepared to provide the efficient glucose oxidation and robust electron production. Furthermore, the charge storage capacity was significantly enhanced through a synergistic combination of the double-layer capacitor mechanism of Ti₃C₂T_x and the pseudocapacitive behavior of PPy. Additionally, the intercalation of PPy NPs expanded the interlayer spacing, promoting electrolyte ion diffusion and charge transfer. The ICBFC-SPS demonstrated exceptional sensitivity with a linear detection range from 0.05 to 100000 ng/L and a detection limit of 9.51 pg/L for the sensitive and selective detection of DEHP in complex environmental and biological samples. The ICBFC-SPS addresses the limitations of traditional methods by providing a self-powered, highly sensitive, and portable platform for rapid, on-site DEHP detection. This work underscores the potential of self-powered sensors as transformative tools for real-time environmental monitoring and public health protection.