Linghu Yaoyao, Lu Dongmei, Wu Chao
School of Chemistry & Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China.
School of Materials Science and Engineering, North University of China, Taiyuan 030051, People's Republic of China.
J Phys Condens Matter. 2021 Apr 20;33(16). doi: 10.1088/1361-648X/abeff9.
Defective (missing S atoms) and nonmetal (C- and N-) doped MoSmonolayers in the 2H and 1T' phases have been evaluated for catalyzing CO oxidation based on first-principles calculations. For the reaction 2CO + O→ 2CO, the oxidization of the first CO molecule is fairly easy and sometimes is even spontaneous, as the O molecule is highly activated or dissociates upon adsorption. However, for the defective (2H-), C-doped (1T'-), and N-doped (2H- and 1T'-) MoSmonolayers, the remaining Oadatom often refuses to react with other CO molecules and is hard to be removed (barrier > 1.20 eV). Only when over the C-doped 2H- and defective 1T'-MoSmonolayers, the removal of the second Oadatom requires to overcome moderate barriers (0.74 and 0.88 eV, respectively) by reacting with another CO molecule via the Eley-Rideal mechanism and the catalysts are recovered. The barriers can be further reduced by applying either tensile or compressive strain to the MoSnanosheet. In contrast, the Langmuir-Hinshelwood mechanism is followed over the metal-containing MoSnanosheets, as the bigger size of metal dopants allow the co-adsorption of CO and O. Therefore, the C-doped 2H- and defective 1T'-MoSmonolayers are promising nonmetal-doped catalysts for CO oxidation.
