Synergistic effect of nitrogen and sulfur co-doped holey graphene for sensitive fenitrothion detection supported by DFT study

The rational design and fabrication of high-performance electrochemical sensors for the determination of environmentally hazardous substances, such as fenitrothion, is of great significance and remains a great challenge. Understanding the interaction between fenitrothion and substrates is critical to inform the design of electrochemical sensors. Herein, we have developed an electrochemical sensor based on nitrogen and sulfur co-doped holey graphene (NS-HG) for fenitrothion. NS-HG with high levels of nitrogen and sulfur leaded to excellent conductivity and a fast electron transfer rate. NS-HG modified electrode showed high electrochemical activity towards fenitrothion. The results were supported by density functional theory (DFT) calculations. The adsorption energy calculations and density of states analysis (DOS) showed that NS-HG exhibited strengthened fenitrothion adsorption and fast electron transfer rate by nitrogen and sulfur co-doping. The fenitrothion sensor based on NS-HG showed an excellent analytical response with high sensitivity, low LOD (0.062 ng·ml−1), excellent selectivity, stability, and satisfactory recoveries for real samples. This research provides new insights into understanding the synergetic effect of co-dopant, and new opportunities for the rational design of electrochemical sensors.