Comparative Study of CO Oxidation on the Surface of Mo‐B‐O and Au/TiO ₂ as a Way for Searching for Alternatives to Noble‐Metal Based Catalysts

ABSTRACT In line with the modern trend of searching for inexpensive alternatives to noble‐metal based catalysts, in the present work a comparative study of the process of carbon monoxide oxidation on the surface of the ternary system Mo‐B‐O, on the one hand, and the Au/TiO 2 (110) system, on the other hand, is carried out. Model systems of both types as substrates were created in a controlled way under ultrahigh vacuum (UHV) conditions and studied in situ by X‐ray photoelectron spectroscopy, Fourier‐transform infrared spectroscopy, low‐energy electron diffraction, scanning tunneling microscopy, temperature‐programmed reaction, and work function measurements. To form the Mo‐B‐O system, a 4‐monolayer‐thick film of boron atoms was first formed on the surface of the Mo(110) crystal, after which the formed film system was annealed to form a binary Mo‐B compound. Then, this compound was oxidized in situ by oxygen admitted to the UHV chamber to form a ternary compound Mo‐B‐O with an atomically ordered surface structure of c(1 × 3)R30 ° symmetry relative to bare Mo(110). The peculiarity of this system is its rather high efficiency of CO oxidation, comparable to that of the Au/TiO 2 system, a prototype widely used in practical applications for low‐temperature CO oxidation. The basis for such high efficiency of Mo‐B‐O is a significant transformation of the electronic state of both CO and O 2 molecules during their co‐adsorption. In addition to high catalytic activity, the Mo‐B‐O system exhibits high stability during the reaction, which, along with its low cost, can be a more acceptable alternative to the currently widely used Au/TiO 2 catalyst.