Transition metal doped graphene-like germanium carbide: Screening of high performance electrocatalysts for oxygen reduction, oxygen evolution, or hydrogen evolution

It is very promising and challenging to design electrocatalysts with high activity for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). Graphene-like germanium carbide (g-GeC) is a new candidate in the field of electrocatalysis due to its stable structure, high specific surface, and adjustable electronic properties. In this work, we systematically studied the electrocatalytic activities to-wards ORR, OER, and HER of the 3d, 4d, and 5d transition metal atom doped g-GeC (M-GeC). According to the scaling relations between binding energies of *OOH and *O as the function of *OH binding strength, conclusion can be made that M-GeC with strong binding strength of *OH tend to show strong binding strength of *O and *OOH. For ORR, the calculated overpotentials show that the catalytic activity of g-GeC is effectively improved after the introduction of Ag and Au, and the eta(ORR) values of Ag-GeC and Au-GeC are 0.44 and 0.46 V, respectively. For OER, Pd-GeC and Ni-GeC are determined as highly active catalysts with low eta(OER) values of 0.41 and 0.55 V, respectively. For HER, the Delta G(*H) value of Mn-GeC is calculated as-0.04 eV, which is very close to the optimal value of 0 eV.