Construction of N-doped carbon nanospheres/ZIF-8 derived dual-hollow carbon nanomesh hierarchical electrocatalyst for enhanced electrochemical sensing of nitrobenzene

As a persistent industrial pollutant, the accurate detection of nitrobenzene (NB) holds critical importance in environmental monitoring and health risk mitigation. Recently, the strategy of using metal-organic frameworks (MOFs) as self-sacrificial precursors/templates to design electrocatalysts with unique structures and excellent electrochemical sensing properties has been regarded as a promising approach. Herein, using ZIF-8 supported on hollow carbon spheres as a self-sacrificing model, a hierarchical electrocatalyst (N HCS@HSC) with a dual - hollow carbon nanostructure composed of N-doped hollow carbon spheres (N HCS) and fishnet-like nanonesh (HSC) was prepared. Benefiting from the interconnected hollow channels in the carbon nanomesh, accelerated electron transfer is achieved, with N-doping further engineering the catalyst's local charge density to optimize active sites. The micro-mesoporous ZIF-8-derived carbon is not only beneficial to the selective recognition of NB, but also enhances the electrically conductive of the catalyst and greatly alleviates the aggregation of active sites. The N HCS@HSC sensing platform demonstrates a broad dynamic response range (0.3–254 μM) with a low detection threshold (0.042 μM) toward NB, coupled with remarkable selectivity and long-term operational stability, which has important implications for human health and environmental safety.