Carbohydrates-Derived Nitrogen-Doped Hierarchical\nPorous Carbon for Ultrasensitive Detection of 4‑Nitrophenol

Abstract

A facile, cost-effective\napproach to obtain sensor electrode materials\nwith excellent electrochemical performance for sensitive and fast\ndetection of 4-nitrophenol (4-NP) is of great importance to the environment\nand human health. Herein, a smart strategy was proposed for fabrication\nof nitrogen-doped hierarchical porous carbon (NPC) material with large\nsurface area and unique hierarchical porous structure derived from\nconveniently available carbohydrates via a facile process. NPC combined\nwith chitosan (CTS) was used to modify an indium-tin oxide (ITO) electrode,\nreferred to as a CTS/​NPC/​ITO electrode, in which CTS\nacted as dispersant and immobilization reagent. On the basis of the\noptimum conditions, 4-NP was successfully deposited on a CTS/​NPC/​ITO\nelectrode and the cathodic deposit of 4-NP showed reversible characteristics\nin a potential range between −0.22 and −0.00 V as well\nas high ionic-electronic conductivity. Moreover, the electrochemical\nreaction kinetics and mechanism of 4-NP were explored in detail by\nCVs, FTIR spectra, and LC–MS. The response sensitivities of\nthe electrode for 4-NP were obtained as 4.85 μA μM^–1, 2.212 μC μM^–1, and\n0.118 μA μM^–1 (RSD ∼ 5%) while\ndetection limits (S/N = 3) were 27.55, 30.10, and 5.44 μM by\napplying cyclic voltammetry, chronocoulometry, and differential pulse\nvoltammetry, respectively. The results were presented to demonstrate\nthat the CTS/​NPC/​ITO electrode had excellent reproducibility,\nrepeatability, good stability, and high selectivity for detecting\n4-NP in real water samples.