Theoretical study of adsorption properties and CO oxidation reaction on surfaces of higher tungsten boride

Most modern catalysts are based on precious metals and rear-earth elements, making some of organic synthesis reactions economically insolvent. Density functional theory calculations are used here to describe several differently oriented surfaces of the higher tungsten boride WB_5-x, together with their catalytic activity for the CO oxidation reaction. Based on our findings, WB_5-x appears to be an efficient alternative catalyst for CO oxidation. Calculated surface energies allow the use of the Wulff construction to determine the equilibrium shape of WB_5-x particles. It is found that the (010) and (101) facets terminated by boron and tungsten, respectively, are the most exposed surfaces for which the adsorption of different gaseous agents (CO, CO₂, H₂, N₂, O₂, NO, NO₂, H₂O, NH₃, SO₂) is evaluated to reveal promising prospects for applications. CO oxidation on B-rich (010) and W-rich (101) surfaces is further investigated by analyzing the charge redistribution during the adsorption of CO and O₂ molecules. It is found that CO oxidation has relatively low energy barriers. The implications of the present results, the effects of WB_5-x on CO oxidation and potential application in the automotive, chemical, and mining industries are discussed.