Design of functionalized double-metal MXenes (M_2M'C_2T_2: M = Cr, Mo, M' = Ti, V) for magnetic and catalytic applications

摘要

Two dimensional (2D) materials have demonstrated huge potential in wide applications ranging from nanodevices to energy storage. In this work, we propose a series of double-metal MXenes functionalized with various terminal atoms (M2M'C2T2), including B, N, O, P and S, based on density-functional theory (DFT) calculation. We screen out a series of stable structures and study their magnetic and electronic properties. We find that the magnetism of M2M'C2T2 can be regulated according to different transition metals and terminal atoms. The magnetic moments of Cr2TiC2T2 and Cr2VC2T2 (T = N, O or S) are mainly contributed by chromium, while those of Mo2VC2T2 (T = N, O or S) are originated from vanadium. We also find that these monolayers are metal with spontaneous conductivity, which is favorable for the electrocatalysis. The Gibbs free energies for the adsorption of hydrogen atoms on Cr2TiC2S2, Cr2VC2S2 and Mo2TiC2P2 are close to zero, indicating their high catalytic activity for hydrogen evolution reaction (HER). Our findings suggest that the functionalized double-metal MXenes are promising materials for magnetic nanodevices and electrocatalysts. (c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.