Probing the Electric Field Effect on the Catalytic Performance of Mn-Doped Graphene to CO Oxidation

The electric field is an effective route to tune the performance of catalysts. Here, we have probed the reaction mechanism of CO oxidation on Mn-doped graphene (Mn-Gr), the effect as a result of the externally applied electric field, and provided a theoretical understanding of the rule by density functional theoy (DFT) calculation. On the basis of DFT calculations, we suggest that electric field has significant impact on the catalytic performance of CO oxidation on Mn-Gr. The reaction barriers for CO 2 formation decrease with increasing CO/O 2 adsorption on Mn-Gr as the electric field decreases from +0.5 to −0.75 V/Å, leading to a greater activation of the O–O bond and then accelerate the CO 2 formation. However, strong binding between CO 2 and Mn-Gr under a larger positive or negative electric field would result in CO 2 desorption difficult and hinder the catalyst regeneration. Therefore, it is proposed that −0.50 F/Å is more appropriate for CO oxidation on Mn-Gr with a lower determined reaction barrier of 0.55 eV when considering the CO 2 formation and desorption, in which the adsorption energy is neither too strong nor too weak. These findings highlight the possibility to manipulate the catalytic performance of the doped graphene to CO oxidation with the electric field controlled which would be helpful for future design and implementation of high performance catalysts.