Three-dimensional porous AuNPs-decorated polyaniline array for ultrasensitive determination of trace Cd(II) and Pb(II) in drinking water

Abstract

Herein, a three-dimensional porous nanomaterials AuNPs-decorated polyaniline nanowire arrays/carbon nanotube (Au-PANI-array@CNT) was constructed by modified dilute polymerization and redox reaction. The Au-PANI-array@CNT exhibited a larger specific surface area (50.03 m2 g−1) and abundant mesopores (average pore size: 19.6 nm), due to the vertical growth of PANI nanowire arrays on CNT. The Au-PANI-array@CNT composite with a three-dimensional interconnected porous structure exhibited abundant electroactive sites and high adsorption capacity, significantly enhancing the deposition and electrochemical reaction process of heavy metals. The AuNPs embedded on PANI nanowries can provide high catalytic activity and multidimensional electron transport channels, further improving the detection sensitivity. A sensing platform with ultra-high sensitivity (2091, 3890 μA μM−1 cm−2) and lower limit of detection (0.18, 0.15 nM) for Cd(II) and Pb(II) determination was developed based on the three-dimensional porous PANI composite. Furthermore, the sensing mechanism of Au-PANI-array@CNT with Cd(II) was explored by XPS and FTIR spectroscopy. The current response only decreased by 5% after being stored at room temperature for 2 months, indicating that the sensor has high reproducibility and stability. Finally, the analysis of drinking water samples verified the excellent practicability of the sensor for the simultaneous measurement of trace levels (nM) of Cd(II) and Pb(II).