Low-temperature and stable CO oxidation of in-situ grown monolithic Mn3O4/TiO2 catalysts

Transition metal oxide catalysts have attracted considerable attention for their promising potential as an alternative to replace noble metal catalysts in the application of various catalytic reactions. Herein, we report the design of monolithic Mn3O4/TiO2 catalysts in-situ grown on Ti mesh substrate for efficient and stable CO oxidation. Porous TiO2 film which is fabricated from the oxidation of Ti mesh using conventional plasma electrolytic oxide process plays an important role in the in-situ nucleation of TiO2 nanosheets with strong adhesion to maintain the long-term stable CO oxidation, as well as providing Ti precursors for the formation of TiO2 nanosheets. The decoration of Mn3O4 co-catalysts on TiO2 nanosheet support could significantly enhance the catalytic property of monolithic Mn3O4/TiO2 catalysts due to the synergetic effect. Thus, a complete CO oxidation can be achieved as low as 160 °C without the involvement of any noble metal catalyst. The novel synthesis strategy of Mn3O4/TiO2 heterogeneous catalysts shows overwhelming advantages of outstanding catalytic performance and superior stability in comparison with other traditional methods of powder-based catalysts. More importantly, it can be extended to the rational design of a variety of TiO2-based transition metal oxide catalysts which can be used for diverse applications including CO oxidation, de-NOx, CHx decomposition etc.