posted on 2018-10-19, 00:00authored byShiyan Wang, Zongxian Yang, Xingli Chu, Weichao Wang
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 Pt1 on VC-TiC(001), Pt2 on VC-TiC(001) has a larger diffusion barrier, indicating
that the VC-TiC(001) substrate can stabilize the Pt dimer
and inhibit its diffusion efficiently. Compared with the Pt1/VC-TiC(001), the DOS plot of Pt2/VC-TiC(001) presents a peak at the Fermi energy caused by variations
in the electronic structure of the VC-TiC(001)-modified
outermost Pt2, which indicates that the supported Pt2 has a high activity on VC-TiC(001). The steady
Pt2/VC-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 OOCO 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 Pt2/VC-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.