Al doped MoS2 monolayer: A promising low-cost single atom catalyst for CO oxidation

Metal doped MoS₂ monolayer as single atom catalyst (SAC) for CO oxidation has been investigated using spin-polarized density functional theory (DFT) calculations. After carefully screening of several normal non-noble metals, Al doped MoS₂ is proven to be the most promising SAC. In Eley-Rideal (ER) mechanism, the energy barrier of the rate-determining step (RDS) is as low as 0.19 eV, which is lower than that of Langmuir-Hinshelwool (LH) mechanism (0.39 eV). It is worth to note that the energy barrier of ER mechanism is lower than most SACs, including those graphene based materials. Very interestingly, in the last step of the ER mechanism, the second CO₂ cannot be dissociated spontaneously because of the strong interaction between CO₂ and Al-MoS₂ with the E_ad of −0.78 eV, until another O₂ was adsorbed to weaken their interaction resulting in the energy barrier of 0.01 eV. Then the left adsorbed O₂ will continue the reaction via ER mechanism. Our results demonstrate that Al-MoS₂ is a promising SAC for CO oxidation.