AlO2: A novel two-dimensional material with a high negative Poisson's ratio for the adsorption of volatile organic compounds

We propose and investigate a novel stable two-dimensional (2D) AlO2 with anomalous stoichiometric ratios based on first-principles calculation. 2D AlO2 has metallic properties. It possesses the rare in-plane and out-of-plane negative Poisson's ratio (NPR) phenomenon, originating from its special sawtooth-like structure. The absolute value of the NPR decreases as the number of layers increases. The adsorption of volatile organic compounds (VOCs) including CH2O, C2H3Cl and C6H6 by AlO2 exhibit small adsorption distance, large adsorption energy, large charge transfer and significant density of states (DOS) changes, indicating the presence of strong interactions. The desorption time of each gas molecule on the AlO2 surface is also evaluated, and the results further suggest that the desorption of VOCs can be controlled by changing the temperature to achieve the recycling of AlO2. These interesting properties make 2D AlO2 a promising material for electronic, mechanical and sensing applications for VOCs.