High-efficient oxidation removal of ethanol from air over ordered mesoporous Co3O4/KIT-6 catalyst

Abstract

In this study, cubic Ia3d mesoporous KIT-6 silica was developed as support to prepare Co3O4/KIT-6 catalysts (COKx, x = 10, 15, 20, 25, and 30 wt%) for OVOCs (ethanol as model compound) catalytic oxidation in air. The prepared COKx catalysts were also characterized by XRD (wide-, low-angle), BET, TEM, H2-TPR, and CO2-TPD. The fixed specific surface area and cubic Ia3d mesoporous structure of KIT-6 provided ordered Ia3d mesoporous structure and high specific surface area for COKx catalysts, but the crystal size, dispersion, reducibility, and oxygen storage-mobility properties of Co3O4, which were based on the ordering of Ia3d mesoporous structure with selected proper mass loading of Co3O4 as 25 wt%, decided the higher catalytic performance of COK25 for ethanol complete oxidation than the others. The T50 and T99 of the prepared COKx catalysts for ethanol oxidation in air were in the range of 215–238 °C and 240–270 °C, respectively, and showed positive relationship with the oxygen storage, desorption, and mobility properties (supply efficiency of reactive oxygen species) of COKx catalysts. The ethanol was completely oxidized to CO2 over COKx as the reaction temperature reached T99, otherwise partially oxidized to acetaldehyde at low reaction temperatures. In addition, the COK25 showed desired CO2 selectivity and T50 and T99 were significantly increased after 7 reaction cycles, revealing good catalytic stability, although the T50 and T99 values increase to 230 and 260 °C, respectively. The COK25 catalyst has showed potential application in OVOCs catalytic purification treatment, due to the available industrialized-preparation method and high catalytic performance.