AuNPs@Al-TDC Metal-Organic Framework: A Hybrid Nanostructure for 3D-Printed Electrochemical Sensors Targeting Diuron

The integration of sustainability principles, green chemistry, and circular economy concepts enables the recycling of polymers such as acrylonitrile-butadiene-styrene (ABS) into innovative and functional devices. In this context, advances in composite materials and conductive filaments are essential for the development of inexpensive and sustainable electrochemical sensors. This study presents a sensor (AuNPs@Al-TDC/3D-CPE) fabricated via 3D printing using recycled ABS filaments, modified with the Al-TDC metal-organic framework (MOF) and gold nanoparticles (AuNPs). The MOF composite was synthesized from tetrachloroauric acid, thiophene-2,5-dicarboxylic acid, dimethylformamide, and formic acid under microwave-assisted hydrothermal conditions, and in a postsynthesis modification, the AuNPs were incorporated. The hybrid materials underwent a comprehensive physicochemical evaluation through spectroscopic, imaging, and electrochemical approaches, confirming both the successful incorporation of the modifiers and the structural integrity of the sensing platform. For its analytical application, the pesticide Diuron was selected as the target molecule for the development of a differential pulse voltammetry (DPV) protocol, whose procedure was systematically optimized using the AuNPs@Al-TDC/3D-CPE. The sensor exhibited a well-defined linear dynamic range between 1.0 and 20.0 μmol L^-1, achieving a detection limit of 0.040 μmol L^-1. Precision was confirmed by relative standard deviations consistently below 7%. Accuracy was further validated through recovery assays in fortified water samples, yielding values between 97% and 105%. The proposed sensor is efficient, cost-effective, and environmentally friendly, representing a promising alternative for the monitoring of emerging contaminants in alignment with the sustainable development goals.