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O: Fachverband Oberflächenphysik
O 94: 2D Materials and their Heterostructures II (joint session DS/HL/O)
O 94.2: Vortrag
Donnerstag, 19. März 2020, 09:45–10:00, CHE 89
Predicting Exfoliability of MAX Phases into MXenes Using Ab-initio Thermodynamics — •Ali Muhammad Malik, Delwin Perera, Jochen Rohrer, and Karsten Albe — Institut für Materialwissenschaft, Technische Universität Darmstadt, Germany
In recent years, research on 2D MAX-derived MXenes has expanded significantly due to their potential application in energy storage systems, electromagnetic interface shielding, electrocatalysis and gas detection. Almost 40 MAX phases have been predicted to be exfoliable based on force constant calculations and exfoliation energies. However, in experiment only 21 have so far been chemically exfoliated. In this work, we present a descriptor that combines calculated reaction energies and surface stabilities under experimentally relevant conditions. In agreement with experiments, we show that this descriptor is indeed capable of predicting the exfoliability of MXenes from Ti-based MAX phases in HF, whereas Cr-based MAX phases are predicted to decompose into Cr3C2 (carbide). We suggest that this descriptor is capable to guide experimental synthesis efforts in particular with respect to the choice of etchant and concentration.