Carbohydrates-Derived Nitrogen-Doped Hierarchical Porous Carbon for Ultrasensitive Detection of 4-Nitrophenol

A facile, cost-effective approach to obtain sensor electrode materials with excellent electrochemical performance for sensitive and fast detection of 4-nitrophenol (4-NP) is of great importance to the environment and human health. Herein, a smart strategy was proposed for fabrication of nitrogen-doped hierarchical porous carbon (NPC) material with large surface area and unique hierarchical porous structure derived from conveniently available carbohydrates via a facile process. NPC combined with chitosan (CTS) was used to modify an indium-tin oxide (ITO) electrode, referred to as a CTS/NPC/ITO electrode, in which CTS acted as dispersant and immobilization reagent. On the basis of the optimum conditions, 4-NP was successfully deposited on a CTS/NPC/ITO electrode and the cathodic deposit of 4-NP showed reversible characteristics in a potential range between -0.22 and -0.00 V as well as high ionic-electronic conductivity. Moreover, the electrochemical reaction kinetics and mechanism of 4-NP were explored in detail by CVs, FTIR spectra, and LC-MS. The response sensitivities of the electrode for 4-NP were obtained as 4.85 mu A mu M-1, 2.212 mu C mu M-1, and 0.118 mu A mu M-1 (RSD similar to 5%) while detection limits (S/N = 3) were 27.55, 30.10, and 5.44 mu M by applying cyclic voltammetry, chronocoulometry, and differential pulse voltammetry, respectively. The results were presented to demonstrate that the CTS/NPC/ITO electrode had excellent reproducibility, repeatability, good stability, and high selectivity for detecting 4-NP in real water samples.