Amino-Functionalized Hierarchical Porous Carbon Derived from Zeolitic Imidazolate Frameworks for Ultrasensitive Electrochemical Sensing of Heavy Metals in Water.

Electrochemical sensing provides a feasible avenue to monitor heavy metal ions (HMIs) in water, whereas the construction of highly sensitive and selective sensors remains challenging. Herein, we fabricated a novel amino-functionalized hierarchical porous carbon by the template-engaged method using ZIF-8 as the precursor and polystyrene sphere as the template, followed by carbonization and controllable chemical grafting of amino groups for efficient electrochemical detection of HMIs in water. The amino-functionalized hierarchical porous carbon features an ultrathin carbon framework with a high graphitization degree, excellent conductivity, unique macro-, meso-, and microporous architecture, and rich amino groups. As a result, the sensor exhibits prominent electrochemical performance with significantly low limits of detection for individual HMIs (i.e., 0.93 nM for Pb, 2.9 nM for Cu, and 1.2 nM for Hg) and simultaneous detection of HMIs (i.e., 0.62 nM for Pb, 1.8 nM for Cu, and 0.85 nM for Hg), which are superior to most reported sensors in the literature. Moreover, the sensor displays excellent anti-interference ability, repeatability, and stability for HMI detection in actual water samples.