A novel electrochemical sensor based on hollow and porous N-doped carbon frameworks embedded with Co nanoparticles for the determination of 4-nitrophenol

4-Nitrophenol (4-NP), a priority pollutant with significant adverse effects on human health and the environment, necessitates the development of sensitive and reliable detection methods. Herein, we report a novel electrochemical sensor for 4-NP detection based on a ZIF-8-derived hollow and porous N-doped carbon framework embedded with uniformly dispersed cobalt nanoparticles (Co-HMCF). This material ingeniously integrates hierarchical structures, N-doping, and Co NPs loading, endowing it with excellent conductivity, a large specific surface area, and superior catalytic activity. These attributes synergistically enhance the electrochemical sensing performance. Under optimal conditions, the achieved wide linear range was 5 μM to 600 μM. The low detection limit of 0.79 μM with high sensitivity of 5.19 μA μM⁻¹ cm⁻² was obtained. Furthermore, the Co-HMCF sensor holds outstanding selectivity and stability. Therefore, the innovative structure and excellent properties of carbon frameworks make them alternative materials for various electrochemical sensors for the detection of other toxic organic pollutants.