Atomic and Electronic Structures of M (=Ni, Fe, NiFe, or FeNi) Adlayer-Modified α-Al2O3(0001) Catalyst Interface

In this study, density functional theory calculation is applied to examine the interfacial electronic and physical structures between the monometallic (Fe, Ni) or bimetallic (NiFe, FeNi) adlayer-modified α-Al2O3(0001) support and its connection with catalytic activity, for example, methane cracking. It is shown that bimetallic interfaces display the key factors for highly catalytic activity as a result of a balance of system stability, favorable d orbital directionality for molecular adsorption, spin quenching, and electron accumulation at the interface. The most stable interfaces promoting the strong metal–support interaction are the monometallic Fe or Ni and bimetallic NiFe interfaces formed with α-Al2O3(0001). Such interfaces are composed of polar/ionic bonds in which bimetallic modification experiences the most significant interfacial M–M (M = Fe or Ni) and Al–O–M bond expansion. In addition to the spin quenching of the metal adlayer, it is identified that interface lattice expansion/distortion upon m...