Detection of nitro-aromatics using C₅N₂ as an electrochemical sensor: a DFT approach

Nitroaromatics impose severe health problems and threats to the environment. Therefore, the detection of such hazardous substances is essential to save the whole ecosystem. Herein, the C₅N₂ sheet is used as an electrochemical sensor for the detection of 1,3-dinitrobenzene (1,3-DNB), trinitrotoluene (TNT), and picric acid (PA) using the PBE0/def2SVP level of theory as implemented in Gaussian 16. The highest interaction energy was observed for the picric acid@C₅N₂ complex. The trend in interaction energies for the studied system is PA@C₅N₂ >TNT@C₅N₂ >1,3-DNB@C₅N₂. The studied systems were further analysed by qualitative and quantitative analyses to determine the interactions between the nitroaromatic analytes and the C₅N₂ sheet. Electronic properties of all analytes@C₅N₂ complexes have been examined by NBO, EDD, FMO and DOS analysis. QTAIM analysis depicts the stronger non-covalent interactions for the PA@C₅N_2, which shows consistency with interaction energy and NCI analysis. Furthermore, NBO and FMO analyses show that the C₅N₂ substrate exhibits high sensitivity and selectivity towards the picric acid compared to TNT and 1,3-DNB nitroaromatics. EDD and DOS analyses are in agreement with NBO and FMO analyses. Furthermore, the recovery time of the studied system has been computed to determine the efficiency of C₅N₂ material as an electrochemical sensor. Overall, the results show that carbon nitride can be a good sensor for the detection of nitroaromatics.