Graphene-MnO2 Hybrid Nanostructure as a New Catalyst for Formaldehyde Oxidation

Graphene-based hybrids for catalysis are currently attracting tremendous attention due to their unique and advantageous properties. However, the application in gas-phase thermal catalysis including the catalytic oxidation of volatile organic compounds (VOCs) remains a theoretical research stage. Here we developed a new use of graphene-based hybrid as a catalyst for formaldehyde (HCHO) oxidation. The hybrid design of MnO2 catalyst incorporated on graphene nanosheets not only exposes more active surface for catalysis, introduces expressways for charge travel during redox reaction, but also brings a large amount of surface OH- species, which simplifies the decomposition pathway of HCHO without the generation and oxidation of intermediate CO. Therefore, this hybrid design enables great performance enhancements in HCHO oxidation as compared to pure MnO2 and even other noble metal catalysts, displaying a much low 100% removal temperature of 65 degrees C. Highly stable performance and excellent recycling ability are also observed over graphene-MnO2 hybrids. Kinetic tests reveal that the introduction of graphene reduces activation energy of MnO2 catalyst from 65.5 to 39.5 kJ mol(-1).