Nitrogen-Doped Porous Carbon Derived from Metal–Organic Gel for Electrochemical Analysis of Heavy-Metal Ion

A nitrogen-doped porous carbon material (N@MOG-C) was prepared by simple pyrolysis of polypyrrole-doped Al-based metal-organic gel (PPy@MOG) at 800 °C. The N@MOG-C possessed a uniform three-dimensional (3-D) interconnected mesoporous structure with a high surface area of 1542.6 m(2) g(-1) and a large pore volume of 0.76 cm(3) g(-1). By using an ionic liquid (IL) to immobilize N@MOG-C on electrode surface, the N@MOG-C was further used for sensitive detection of heavy metal ion. The doping of nitrogen-endowed N@MOG-C with faster electron transfer kinetics than other carbon materials such as MOG-C, multiwalled carbon nanotubes, and graphene. The N@MOG-C-modified electrode showed a high effective area, because of the porous structure. Under optimized conditions, the N@MOG-C-based sensor could detect Cd ions present in concentrations of 0.025-5 μM, with a detection limit of 2.2 nM. The mesoporous structure, fast electron transfer ability, and simple and green synthesis of N@MOG-C made it a promising electrode material for practical applications in heavy-metal-ion sensing.