Computational Exploration of Nickel Nanoclusters as Nano Sensors for Toxic Gas Detection

ABSTRACT In this study, the structural, electronic, and adsorption properties of Ni 2–5 nanoclusters and their Fe‐ and Zn‐doped counterparts were systematically investigated using density functional theory (DFT) to evaluate their suitability for toxic gas sensing applications. Key properties such as density of states (DOS), adsorption energy, HOMO–LUMO gap, infrared (IR) spectra, recovery time, and electrostatic potential (ESP) were thoroughly analyzed. All pristine and doped clusters exhibited negative formation energies and no imaginary frequencies in their IR spectra, confirming structural and dynamical stability. Notably, increasing the cluster size enhanced adsorption strength, with Ni 5 showing the highest adsorption energies (−2.149 eV for HCN and −1.687 eV for CNCl). Unlike prior studies, this work provides a comparative insight into the influence of Fe and Zn doping across Ni 2–5 clusters, highlighting how dopant type and cluster size synergistically tune gas adsorption behavior. These findings, supported by favorable electrostatic and electronic structural characteristics, offer valuable design principles for next‐generation nanoscale chemical sensors aimed at detecting hazardous gases such as HCN and CNCl in real‐world environments.