High‐Performance Co‐MnOx Composite Oxide Catalyst Structured onto Al‐Fiber Felt for High‐Throughput O3 Decomposition

Abstract

AbstractA highly active and efficient thin‐felt Al‐fiber‐structured Co‐MnOx composite oxide catalyst (named Co‐MnOx‐Al) with unique form factor and high permeability is developed for high‐throughput catalytic decomposition of gaseous ozone (O3). Thin‐sheet Al‐fiber felt (60 μm diameter; 90 vol % voidage) chips underwent a steam‐only oxidation and calcination for endogenously growing a 0.7‐μm‐thick mesoporous layer of γ‐Al2O3 nanosheets along with the Al‐fiber. Cobalt and manganese were placed onto the ns‐γ‐Al2O3/Al‐fiber chips by incipient wetness co‐impregnation method. The best catalyst is the one with a Co/Mn molar ratio of 0.36 and Co‐Mn loading of 5 wt % after calcining at 500 °C (named Co‐MnOx(0.36)‐Al), being able to achieve full O3 conversion at 25 °C for a feed gas containing 1000±30 ppm O3, using a high gas hourly space velocity of 48000 mL gcat.−1 h−1; full O3 conversion is retained in the absence of moisture till the testing end after 720 min; in case with a relative humidity of 50 %, O3 conversion slides from 88 % of the initial value to a flat of ∼66 % within 90 min. CoOx modification is paramount for improved formation of Mn2+ species while leading to the highest fraction of (Mn2++Mn3+) in total (Mn2++Mn3++Mn4+) and more oxygen vacancies on Co‐MnOx(0.36)‐Al catalyst surface.