Hierarchically porous monoliths based on low-valence transition metal (Cu,Co, Mn) oxides: gelation and phase separation |
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| Authors: | Xuanming Lu Kazuyoshi Kanamori Kazuki Nakanishi |
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| Institution: | Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan;Institute for Integrated Cell-Material Sciences, Kyoto University Institute for Advanced Study, Kyoto University, Kyoto 606-8501, Japan;Division of Materials Research, Institute of Materials and Systems for Sustainability, Nagoya University, Nagoya 464-8601, Japan |
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| Abstract: | Hierarchically porous monoliths based on copper (Cu), cobalt (Co) and manganese (Mn) oxides with three-dimensionally (3D) interconnected macropores and open nanopores were prepared using metal bromides as precursors via a sol–gel process accompanied by phase separation. The difficulty of gelation for low-valence metal cation was overcome by introducing a highly electronegative Br atom near to the metal atom to control the rates of hydrolysis and polycondensation. The 3D interconnected macropores were obtained using appropriate polymers to induce phase separation. The domain sizes of macropores and skeletons can be controlled by reaction parameters such as concentration and/or average molecular weight of polymers, and the amount of hydrochloric acid. The crystalline metal oxide monoliths with their 3D interconnected macroporous structure preserved were obtained after heat treatment in air. |
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| Keywords: | hierarchically porous monolith low-valence transition metal oxide 3D interconnected macropore sol– gel process phase separation |
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