The remarkable effect of alkali earth metal ion on the catalytic activity of OMS-2 for benzene oxidation.

The remarkable effect of alkali earth metal ion on the catalytic activity of OMS-2 for benzene oxidation.
Chemosphere. 2020 Jul;250:126211
Authors: Ni C, Hou J, Li L, Li Y, Wang M, Yin H, Tan W
Abstract
Cryptomelane-type octahedral molecular sieve (OMS-2) is one of the most promising catalysts for VOCs oxidation, and introduction of metal ions in OMS-2 tunnel is widely used for tailoring its catalytic activity. Here, different types of alkali earth metal ions with the same X/Mn atomic ratio of approximately 0.012 (X represents Mg2+, Ca2+, and Sr2+) were successfully introduced into OMS-2 tunnel by a one-step redox reaction. The catalytic test showed that introducing alkali earth metal ions into tunnels had a considerable effect on the catalytic performance of OMS-2 for benzene oxidation. The Sr2+ doped OMS-2 catalyst exhibited the better catalytic activity compared with those of Mg-OMS-2 and Ca-OMS-2 samples, and was also superior to a commercial 0.5% Pt/Al2O3 catalyst, as evidenced by its low reaction temperatures of T50 = 200 °C and T90 = 223 °C (corresponding to benzene conversions at 50% and 90%, respectively). The origin of the considerable effect of alkali earth metal doping on the catalytic activity of OMS-2 catalysts was experimentally and theoretically investigated by an 18O2 isotopic labeling experiment, CO temperature-programmed reduction, O2 temperature-programmed oxidation, and density functional theory calculati...

Source: Chemosphere - May 29, 2020 Category: Chemistry Authors: Ni C, Hou J, Li L, Li Y, Wang M, Yin H, Tan W Tags: Chemosphere Source Type: research