Theoretical study on iron and nitrogen co-doped graphene catalyzes CO oxidation

Carbon monoxide oxidation is a famous typical polyphase catalytic reaction, which can convert toxic gases into non-toxic substances, thus reducing environmental pollution. The traditional catalytic reaction has high energy barriers and low energy efficiency, while the single metal atom was inserted into the thin graphene with excellent electronic properties to form a special structure, which has extraordinary catalytic properties. Based on the first principle calculation method, the different reaction mechanism of CO oxidation in nitrogen co-doped single vacancy and double vacancy (FeN-SV and FeN-DV) was studied systematically, and its stable structure was analyzed to find the optimal catalytic reaction path. For FeN-SV, the energy barriers of a new trimolecular co-adsorption mechanism (2*CO+*O2 ->*OOCO+*CO ->*O+*CO+CO2 ->*CO21 ->*CO22), which has not been reported yet, was only 0.525 eV. The rate-determining step (RDS) for FeN-SV (FeN-DV) is *CO+*O2 ->*OOCO ->*O+CO2 ->*O+CO -> CO2, which is also very beneficial to CO oxidation, was 0.604 eV (0.660 eV). The findings revealed FeN-SV and FeN-DV can be used as a low cost, high efficiency for CO catalytic oxidation.