Transition-Metal Ni6−xCux (x = 0–6)/Hexagonal Boron Nitride Composite for CO Detection: A DFT Study

The development of highly selective and sensitive gas sensors is essential for detecting toxic pollutants, such as carbon monoxide (CO), which pose severe health and environmental risks. In this work, the adsorption of CO molecules on Ni6−xCux (x = 0–6) clusters supported on hexagonal boron nitride quantum dots with nitrogen vacancies (h-BNVQDs) is explored through density functional theory (DFT) calculations. For this purpose, the stability of the metallic clusters supported on the boron nitride sheet was calculated, and the adsorption properties of the CO molecule on the Ni6−xCux (x = 0–6)/h-BNVQDs composite were determined. The results demonstrated a high binding energy between Ni6−xCux (x = 0–6) clusters and the h-BNVQDs sheets, suggesting that Ni-Cu clusters are highly stable on h-BNVQDs sheets. For CO adsorption, adsorption energy and charge transfer calculations indicated that the Ni6 and Ni6−xCux (x = 2 and 3) clusters exhibit the strongest CO binding and highest charge transfer, suggesting them as good candidates for CO gas sensing. These findings provide theoretical insights into the rational design of bimetallic catalysts for gas-sensing applications.