Single-atom catalysis for carbon dioxide dissociation using greigite-supported M₁/Fe₃S₄(111) (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) under electrostatic fields

Single transition metal adatoms (M) supported on a solid surface –here the reactive greigite M₁/Fe₃S₄(111) surface– combine the best properties of homogeneous and heterogeneous catalytic systems and are highly selective materials capable of altering the pathway of difficult reactions. We have employed state-of-the-art first-principles simulations to investigate the process of carbon dioxide (CO2) dissociation on the single-atom catalyst (SAC) M₁/Fe₃S₄(111). We discuss how reconstructions of the symmetrical stacking sequence of charged atomic planes determines the possible stable non-polar terminations of the Fe3S4(111) surface. The thermodynamic stability and the work function are the main descriptors that are affected by external electrostatic fields, both for the most stable termination of the pristine Fe3S4(111) surface as well as the M₁/Fe₃S₄(111) catalysts. We present the electron density plots for the M₁/Fe₃S₄(111) surfaces, which show that the M adatom forms covalent metal-support interactions (CMSI). In general, positive external electrostatic fields enhance the adsorption properties of the M₁/Fe₃S₄(111) catalysts towards the CO₂ molecule, which activates chemically upon interaction. Our energy profiles for the dissociation of the CO₂ molecule show that carefully selected transition metal adatoms, such as V, Cr and Co, and positive external electrostatic fields can be used to tune the catalytic properties of SACs.