Unveiling the role of metal-doped BNC2 monolayer for selective gas adsorption: A DFT investigation

Abstract

Developing effective gas sensors is crucial for environmental monitoring, safety, and industrial applications. Two-dimensional (2D) materials are increasingly investigated as gas-sensing platforms due to their high surface-to-volume ratios and tunable electronic properties. In this study, we utilize density functional theory (DFT) to investigate the gas-sensing properties of the BNC₂ monolayer (ML), focusing on the adsorption of CO, CO₂, NO, NO₂, and HCN on pristine and metal-doped (Li, Mg, and Al) BNC₂. Our results reveal that all doped metal atoms are strongly bound to the BNC₂ surface, though slightly protruding from the plane. Among the dopants, Al-doped BNC₂ exhibits the strongest interaction with gas molecules, particularly NO and NO₂, while Mg-doped BNC₂ shows a balanced interaction, making it highly suitable for selective gas sensing. Li-doped BNC₂, in contrast, demonstrates weaker interactions, leading to faster desorption times. The charge transfer analysis indicates that most gas molecules act as charge acceptors, with NO and NO₂ showing significant electron gain from Mg- and Al-doped surfaces. Additionally, recovery time calculations suggest that metal doping significantly enhances gas-sensing performance compared to pristine BNC₂, particularly for NO and NO₂ detection. This work underscores the versatility of metal-doped BNC₂ monolayers, both in gas sensing and gas capture, contributing to the development of advanced sensing technologies and environmental sustainability solutions.