Advanced Functional Materials, Vol.20, No.19, 3373-3382, 2010
Titanium Containing gamma-MnO2 (TM) Hollow Spheres: One-Step Synthesis and Catalytic Activities in Li/Air Batteries and Oxidative Chemical Reactions
Titanium containing gamma-MnO2 octahedral molecular sieves having hollow sphere structures are successfully prepared for the first time using a one-step synthesis method. Titanium cations are used as structure directing agents in the synthesis process. The assembly of the hollow spheres is carried out at the beginning of the process. Various techniques including XRD, N-2 adsorption, SEM, EDX, RAMAN, TEM, XPS, and TGA are employed for the materials characterization. Ti is incorporated into the MnO2 framework in isolated sites, and TiO2 phases (anatase and rutile) are not observed. When introduced in medium-sized lithium air batteries, the materials give very high specific capacity (up to 2.3 A h g(-1)). These materials are also catalytically tested in the oxidation of toluene with molecular oxygen at atmospheric pressure, showing significant oxidative catalytic activities in this difficult chemical reaction.