Sulfur-tolerant mechanism in catalytic combustion of toluene over Co/5Mg-γ-Al2O3 catalyst: Dual functions of MgO

Using toluene catalytic combustion as a probe reaction, simulating quantitative sulfur poisoning by in situ thermal decomposition of ammonium sulfate solution, the study used MgO modified γ-Al2O3 to support cobalt-based catalyst, and the result displayed that the catalyst exhibited excellent sulfur poisoning resistance. The successful construction of MgO-Al2O3 heterogeneous interface weakened the interaction between Co and Al and reduced the production of inactive CoAl2O4. Besides that, it fixed sulfur species and formed MgSO4 to protect active components. The dual function of MgO have been proved by various characterization experiments. The modification of γ-Al2O3 by the appropriate amount of MgO could improve the catalytic activity of Co/γ-Al2O3. Meanwhile, T100 increased from 300 °C to 330 °C after 1.6 wt.% sulfur poisoning and we concluded that the decrease in catalytic performance was not caused by the loss of active Co, but by the decrease of specific surface area and lattice oxygen activity.