Design of Efficient Catalysts for CO Oxidation on Titanium Carbide-Supported Platinum via Computational Study

摘要

The formation, geometries, electronic structures, and catalytic properties of monovacancy and divacancy of the defective TiC(001) with single Pt atom and Pt dimer are systematically studied based on the first-principles calculations. Compared with the diffusion barrier of Pt-1 on V-C-TiC(001), Pt-2 on V-C-TiC(001) has a larger diffusion barrier, indicating that the V-C-TiC(001) substrate can stabilize the Pt dimer and inhibit its diffusion efficiently. Compared with the Pti/Vc-TiC(001), the DOS plot of Pt-2/V-C-TiC(001) presents a peak at the Fermi energy caused by variations in the electronic structure of the V-C-TiC(001)-modified outermost Pt-2, which indicates that the supported Pt-2 has a high activity on Vc-TiC(001). The steady Pt-2/V-C-TiC(001) catalyst exhibits outstanding activity for CO oxidation in the Langmuir-Hinshelwood (LH) and termolecular Eley-Rideal (TER) mechanisms for the rate-limiting step of the 0000 and OCOOCO dissociation, having the energy barriers of 0.32 and 0.52 eV, respectively, which are both more preferable than the Eley-Rideal (ER) mechanism. Therefore, the Pt-2/V-C-TiC(001) is quite efficient for CO oxidation. The existing results are expected to help us to develop efficient catalysts that are highly tolerant to CO poisoning.