Pt/MnO₂ nanosheets: facile synthesis and highly efficient catalyst for ethylene oxidation at low temperature

Transition metal oxides (TMOs) have been playing an indispensible role in the catalysis of redox reactions. In particular, two dimensional TMOs expose their surface/edge sites to a large extent, which brings unique catalytic features such as greatly enhanced catalytic activities. Here a series of MnO₂ nanosheets have been facilely synthesized by a simple redox reaction between KMnO₄ and 2-(N-morpholino)ethane sulfonic acid (MES) at room temperature. Among the obtained MnO₂ samples, MnO₂-48 h showed the highest performance in removing C₂H₄ resulting from its highest concentration of surface active oxygen species. To further improve the oxidation activity of the catalyst, a small amount of Pt nanoparticles (NPs) was subsequently loaded on MnO₂ nanosheets (Pt/MnO₂) by a colloidal deposition method. The Pt/MnO₂ demonstrated enhanced catalytic performance and maintained complete removal of 20 ppm C₂H₄ at 50 °C for at least 12 h, which can be attributed to the large amount of adsorbed oxygen species and synergetic catalytic effect between Pt and the MnO₂ support.