DFT and Green’s Function Formalism Investigation of 2D Penta-NiN ₂ Nanosheets: Implications for Catechol Sensing

Inspired by the recent successful synthesis of the penta-NiN 2 monolayer (ACS Nano, 2021, 15, 13539), we explore its potential as a highly sensitive and reusable sensor for the detection of the catechol (CC) biomolecule using the first-principles density functional theory (DFT) combined with Green’s function formalism. Our comprehensive study reveals that CC adsorption significantly modulates the electronic properties of the penta-NiN 2 surface. In the presence of water, the adsorption energy increases from −0.85 eV (vacuum) to −0.89 eV (aqueous), indicating a stronger interaction. Projected density of states (PDOS) and Bader charge analysis show ∼0.03 e charge transfer from CC to the NiN 2 nanosheet. Notably, the adsorption of CC leads to a ∼1.7-fold increase in current through the NiN 2 nanosheet channel, highlighting its potential in sensing applications. Reduced density gradient (RDG) analysis offers further insight into the noncovalent interactions governing the adsorption process. Ab-initio molecular dynamics (AIMD) simulations confirm the thermal stability of the system at 300 K. Moreover, the calculated recovery times under visible light are 0.28 s in dry and 1.28 s in aqueous environment, demonstrating excellent sensor reusability. These results position the penta-NiN 2 nanosheet as a promising candidate for a real-time, reusable CC biosensing platform with high sensitivity, stability, and rapid response.