Synthesis and carbon monoxide purification performance of ZSM-5 molecular sieve Co-doped Mn/V catalytic material

Abstract

Trackless, rubber-tired, diesel-powered vehicles are widely used in the mining industry. In recent years, the use of high-performance catalysts to remove carbon monoxide (CO) from diesel vehicle exhaust has attracted much attention. In this paper, a series of manganese-vanadium doped ZSM-5 molecular sieve catalysts were prepared by an impregnation method. The structures of the catalysts were characterized and experiments were conducted to evaluate their performance. The CO catalytic oxidation performance experiments revealed that Mn_0.6-V_0.4-ZSM-5 had the best performance, with a conversion rate of 97.5 % at 300 °C. The catalyst was also tested for water resistance and stability. Kinetic measurements were performed and the fitted activation energy was 22.68 kJ/mol. Characterization studies revealed that the surface defects formed by Mn and V doping provided a large number of active sites and oxygen vacancies for CO oxidation, increased the number of adsorbed oxygen species on the surface, and enhanced the redox capacity through the interaction of Mn⁴⁺ and V⁵⁺ to improve the catalytic oxidation performance of the catalyst. The adsorption configurations, adsorption energy (E_bin), and formation energy of oxygen vacancies of CO at different adsorption sites and different active fractions were calculated with density functional theory. The E_bin of CO on Mn₂V₂O₇, the active fraction of Mn_0.6-V_0.4-ZSM-5, was −1.29 eV, which was the most stable adsorption configuration. This configuration had good oxygen mobility, and was conducive to CO catalysis, confirming the characterization and performance experiments.