Additionally, to gain insight into the reaction mechanism, the activation barrier was calculated using the climbing image nudge elastic band (CI-NEB) method . It is worth noting that conducting NEB calculations with support consisting of over 200 atoms is a computationally demanding task. Therefore, we excluded the effect of support to estimate the activation barrier for SO3 dissociation. ). This reduction is ascribed to the formation of strong S-O bonds at the anchor sites, which cover more than 50% of the surface area and pore volume. However, there is no significant change in the catalytic activity of the FeCo2O4 /SiC-Pretrt even after a 100 h run. Therefore, FeCo2O4 /SiC-Pretrt is a better catalyst for high-temperature sulfuric acid decomposition.