DFT Study of MAX Phase Surfaces for Electrocatalyst Support Materials in Hydrogen Fuel Cells

In moving towards a greener global energy supply, hydrogen fuel cells are expected to play an increasingly significant role. New catalyst support materials are being sought with increased durability. MAX phases show promise as support materials due to their unique properties. The layered structure gives rise to various potential (001) surfaces. DFT is used to determine the most stable (001) surface terminations of Ti₂AlC, Ti₃AlC₂ and Ti₃SiC₂. The electrical resistivities calculated using BoltzTraP2 show good agreement with the experimental values, with resistivities of 0.460  µΩ  m for Ti₂AlC, 0.370  µΩ  m for Ti₃AlC₂ and 0.268  µΩ  m for Ti₃SiC₂. Surfaces with Al or Si at the surface and the corresponding Ti surface show the lowest cleavage energy of the different (001) surfaces. MAX phases could therefore be used as electrocatalyst support materials, with Ti₃SiC₂ showing the greatest potential.