Hierarchical porous carbon foam embedded with readily accessible atomic iron sites for efficient electrochemical nitrite sensing

Abstract

The potential toxicity of nitrite in drinking water or food poses a major threat to human health. The development of effective, sensitive and stable sensors to realize the efficient detection of nitrite is therefore urgently required. In this work, a hierarchical porous carbon foam embedded with readily accessible atomic iron sites was designed and synthesized for sensitive electrochemical nitrite sensing. It is facilely constructed through the polyacrylonitrile-templated growth of covalent organic frameworks (COFs), followed by post-modification and graphitization. The atomic iron sites in the hierarchical porous structure help to increase the number of active sites and detection efficiency. The electrochemical sensor based on the optimized electrode exhibits excellent electrocatalytic activity, high sensitivity for the detection of nitrite, with a sensitivity of 654.4 μA mM⁻¹ cm⁻² and a detection limit of 0.158 μM (S/N = 3). This method broadens the application of COFs in the field of electrochemical sensing, and has great potential for use in a wide range of applications for nitrite detection in food and environmental fields.