Palladium\nNanoparticle Incorporated Porous Activated Carbon: Electrochemical\nDetection of Toxic Metal Ions

Abstract

A facile method has been developed\nfor fabricating selective and sensitive electrochemical sensors for\nthe detection of toxic metal ions, which invokes incorporation of\npalladium nanoparticles (Pd NPs) on porous activated carbons (PACs).\nThe PACs, which were derived from waste biomass feedstock (fruit peels),\npossess desirable textural properties and porosities favorable for\ndispersion of Pd NPs (ca. 3–4 nm) on the graphitic PAC substrate.\nThe Pd/PAC composite materials so fabricated were characterized by\na variety of different techniques, such as X-ray diffraction, field-emission\ntransmission electron microscopy, gas physisorption/chemisorption,\nthermogravimetric analysis, and Raman, Fourier-transform infrared,\nand X-ray photon spectroscopies. The Pd/PAC-modified glassy carbon\nelectrodes (GCEs) were exploited as electrochemical sensors for the\ndetection of toxic heavy metal ions, viz., Cd²⁺, Pb²⁺, Cu²⁺, and Hg²⁺, which showed superior\nperformances for both individual as well as simultaneous detections.\nFor simultaneous detection of Cd²⁺, Pb²⁺, Cu²⁺, and Hg²⁺, a linear response in the ion concentration\nrange of 0.5–5.5, 0.5–8.9, 0.5–5.0, and 0.24–7.5\nμM, with sensitivity of 66.7, 53.8, 41.1, and 50.3 μA\nμM^–1 cm^–2, and detection\nlimit of 41, 50, 66, and 54 nM, respectively, was observed. Moreover,\nthe Pd/PAC-modified GCEs also show perspective applications in detection\nof metal ions in real samples, as illustrated in this study for a\nmilk sample.