Two-dimensional iron-phthalocyanine (Fe-Pc) monolayer as a promising single-atom-catalyst for oxygen reduction reaction: a computational study.

Searching for low-cost non-Pt catalysts for oxygen reduction reaction (ORR) has been a key scientific issue in the development of fuel cells. In this work, the potential of utilizing the experimentally available two-dimensional (2D) Fe-phthalocyanine (Fe-Pc) monolayer with precisely-controlled distribution of Fe atoms as a catalyst of ORR was systematically explored by means of comprehensive density functional theory computations. The computations revealed that O2 molecules can be sufficiently activated on the surface of the Fe-Pc monolayer, and the subsequent ORR steps prefer to proceed on the Fe-Pc monolayer through a more efficient 4e pathway with a considerable limiting potential of 0.68 V. Especially, the Fe-Pc monolayer is more stable than the Fe-Pc molecule in acidic medium, and can present good catalytic performance for ORR on the addition of axial ligands. Therefore, the Fe-Pc monolayer is quite a promising single-atom-catalyst with high efficiency for ORR in fuel cells.