Sensing Performance of Heptazine-Based C3N4 Quantum Dot Toward Highly Toxic Environmental Pollutants, Amides, and Acetyl Derivatives

The detection of toxic molecules has gained imperial attention to protect living organisms and their environment. The broadly explored sensor behaviour of triazine-based C 3 N 4 reveals their ultra-high sensitivity towards numerous toxic molecules e.g ., chemical welfare agents. However, another potential analogue of C 3 N 4 composed of heptazine exhibits remarkable electrical and optical properties but has not been much explored in sensor technology, especially for toxic pollutants. Keeping this in mind, the sensing performance of heptazine-based g-C 3 N 4 is explored for the detection of toxic amides by using First Principles calculations. In this context, acryloyl amide (C 2 H 3 CONH 2 ), acryloyl chloride (C 2 H 3 COCl), fluoroacetic acid (C 2 H 3 FCOOH), flouroaceta amide (C 2 H 2 FONH 2 ), flouroacetyl chloride (C 2 H 2 FOCl) are selected as toxic pollutants; herein, for the ease of understanding, these molecules are represented as AAM, ACl, FAAc, FAA, & FACl, respectively. The electrochemical sensitivity of g-C 3 N 4 is determined via geometric, energetic, and electronic properties analysis, whereas the photochemical sensitivity is explored by UV–Vis absorption analysis based on TD-DFT calculations. The interaction energies of studied molecules on C 3 N 4 range between − 9.09 and - 23.39 kcal/mol depending upon the type of interactions e.g., hydrogen bonding or dispersion, which are explained on the basis of Symmetry Adopted Perturbation Theory, Non-Covalent Interaction Index, and Quantum Theory of Atoms in Molecules analyses. The density of State analysis, Frontier Molecular Orbitals and NBO charge transfer characterized that the electronic behaviour of g-C3N4 can be an effective sensor material with a semiconducting nature and significant charge transfer. Lastly, UV–Vis absorption analysis confirms the photosensitivity of g-C 3 N 4 upon interaction with toxic molecules.