Revelation of Mn4+-Osur-Mn3+ active site and combined Langmuir-Hinshelwood mechanism in propane total oxidation at low temperature over MnO2

Mn-based oxides exhibit attractive catalytic activity for VOCs oxidation, but the catalytic mechanism and kinetics are still significant challenges and rarely mentioned. Therefore, we prepared OMS-2 manganese oxide octahedral molecular sieve with alpha-MnO(2 )crystal phase as model compound. By analyzing the properties of the surface chemical states of the catalysts in different reaction stages, combined with the control experiments, the coordination of Mn4+-O-sur-Mn3+ was confirmed as the active site at low temperature. Meanwhile, the reaction path of propane catalytic oxidation on MnO2 surface based on condensation mechanism was proved by in-situ spectroscopy and density functional theory calculation. And kinetic studies revealed that the catalytic combustion of propane processed through Langmuir-Hinshelwood mechanism at low temperature. All these systematic study results supplied a well-defined understanding for the propane combustion over manganese oxide.

Automated summary

This study analyzed the catalytic activity of OMS-2 manganese oxide octahedral molecular sieve and revealed that the coordination of Mn4+-O-sur-Mn3+ was the active site at low temperature. The reaction path of propane catalytic oxidation on MnO2 surface based on condensation mechanism was proved, and kinetic studies showed that the reaction proceeded through Langmuir-Hinshelwood mechanism.