title: Crystalline mesoporous K(2-x)Mn₈O₁₆ and ε-MnO₂ by mild transformations of amorphous mesoporous manganese oxides and their enhanced redox properties.
abstract: Synthesis of crystalline mesoporous K(2-x)Mn8O16 (Meso-OMS-2), and ε-MnO2 (Meso-ε-MnO2) is reported. The synthesis is based on the transformation of amorphous mesoporous manganese oxide (Meso-Mn-A) under mild conditions: aqueous acidic solutions (0.5 M H(+) and 0.5 M K(+)), at low temperatures (70 °C), and short times (2 h). Meso-OMS-2 and Meso-ε-MnO2 maintain regular mesoporosity (4.8-5.6 nm) and high surface areas (as high as 277 m(2)/g). The synthesized mesoporous manganese oxides demonstrated enhanced redox (H2-TPR) and catalytic performances (CO oxidation) compared to nonporous analogues. The order of reducibility and enhanced catalytic performance of the samples is Commercial-Mn2O3 < nonporous-OMS-2 < Meso-Mn2O3 < Meso-OMS-2 < Meso-ε-MnO2 < Meso-Mn-A.
authors: Department of Chemistry and ‡Department of Chemistry Institute of Materials Science, University of Connecticut , U-3060, 55 North Eagleville Road, Storrs, Connecticut 06269, United States.
authors: Altug S
authors: AS
authors: Poyraz
authors: Wenqiao
authors: W
authors: Song
authors: David
authors: D
authors: Kriz
authors: Chung-Hao
authors: CH
authors: Kuo
authors: Mohammad S
authors: MS
authors: Seraji
authors: Steven L
authors: SL
authors: Suib