Hierarchical branched alpha-MnO2: one-step synthesis and catalytic activity

Hierarchical pine tree-like alpha-MnO2 architectures are prepared by a facile one-step method without any template. The hierarchical alpha-MnO2 is composed of branched alpha-MnO2 short nanorods assembled onto the backbone of an alpha-MnO2 long nanowire. Time-dependent experiment shows that the growth process of the branched alpha-MnO2 nanostructures is the formation of beta-MnOOH and then the transformation to a alpha-MnO2 branched structure in a step by step manner. Owing to its specific structure features, the hierarchical pine tree-like alpha-MnO2 exhibits superior catalytic performance in the catalytic combustion of dimethyl ether with a light-off temperature (T-10) at 169 degrees C and a complete conversion temperature (T-90) of 235 degrees C, which is far better than commercial MnO2.