Selective and sensitive detection of lead Pb(II) ions: Au/SWNT nanocomposite-embedded MOF-199

Metal organic frameworks (MOFs) are best known for their highly crystalline structures, ultrahigh porosity with considerable surface area and tunable physicochemical properties. The promising architecture of MOFs, where central metal atoms are surrounded by organic ligands secures their prominent candidature for advanced sensor technology. In this work, we have synthesized gold (Au) nanoparticles and single-walled carbon nanotube (SWNTs) nanocomposite-incorporated copper benzene tricarboxylate (MOF-199) MOF (Au/SWNTs@MOF-199) by solvothermal route. The synthesized Au/SWNTs@ MOF-199 has rigorously characterized with spectroscopic, morphological, structural, electrochemical, thermal, Brunauer–Emmett–Teller (BET) surface area using N2 adsorption isotherm methods. The proposed Au/SWNTs@MOF-199 nanocomposite exhibited excellent electrochemical characteristics and sensing performance towards Pb2+ ions. The calibration plot for the electrochemical response of Au/SWNTs@MOF-199 towards Pb2+ ions was recorded for the range of 0.1 mM–1 pM (R2 = 99.58)) with a limit of detection of 25 pM/L and a rapid response time of a few seconds with high sensitivity, selectivity, repeatability and reproducibility as determined by error bar diagram. These results indicate the significant potential of Au/SWNTs@MOF-199 nanocomposites as highly sensitive Pb2+ ion sensor.