Nano-micrometer-architectural acidic silica prepared from iron oxide of Leptothrix ochracea origin.
Nano-micrometer-architectural acidic silica prepared from iron oxide of Leptothrix ochracea origin.
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由 Leptothrix ochracea 来源的氧化铁制备的纳米微米结构酸性二氧化硅。
DOI：
10.1021/am401029r
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发表时间：
2013
影响因子：
9.5
通讯作者：
J. Takada
中科院分区：
文献类型：
--
作者：
H. Hashimoto;Atsushi Itadani;Takayuki Kudoh;S. Fukui;Y. Kuroda;M. Seno;Y. Kusano;Y. Ikeda;Y. Benino;T. Nanba;M. Nakanishi;T. Fujii;J. Takada
我们以天然无定形氧化铁为原料，制备了具有结构硅的纳米微米级酸性二氧化硅，这种结构硅是氧化铁细长线虫的产物。起始材料在500℃的H2气流中进行热处理，使α-Fe晶相颗粒偏析，然后在1M盐酸中溶解，去除α-Fe颗粒，得到灰色的沉淀。经鉴定为含一定量铁(Si/Fe=60)的无定形二氧化硅。无定形二氧化硅保持了起始材料的纳米微结构-~1-μm直径微米管，由几十纳米大小的内球形和外纤维结构组成-并具有许多大孔，这些孔很可能是由于α-Fe颗粒在微米管壁上的偏析而形成的。无定形二氧化硅的最小粒径为10 nm，比表面积为550m(2)/g，具有0.7 nm的微孔。通过使用吡啶蒸气作为探针分子来评估无定形二氧化硅中的活性中心，我们发现它具有相对较强的Brnsted和Lewis酸性中心，即使在400°C抽空后也不会解吸吡啶。这种新的二氧化硅材料的酸性通过两个典型的催化反应得到证实：开环反应和Friedel-Craft型反应，这两种反应都需要酸催化剂。
We prepared nano-micrometer-architectural acidic silica from a natural amorphous iron oxide with structural silicon which is a product of the iron-oxidizing bacterium Leptothrix ochracea. The starting material was heat-treated at 500 °C in a H2 gas flow leading to segregation of α-Fe crystalline particles and then dissolved in 1 M hydrochloric acid to remove the α-Fe particles, giving a gray-colored precipitate. It was determined to be amorphous silica containing some amount of iron (Si/Fe = ~60). The amorphous silica maintains the nano-microstructure of the starting material-~1-μm-diameter micrometer-tubules consisting of inner globular and outer fibrillar structures several tens of nanometer in size-and has many large pores which are most probably formed as a result of segregation of the α-Fe particles on the micrometer-tubule wall. The smallest particle size of the amorphous silica is ~10 nm, and it has a large surface area of 550 m(2)/g with micropores (0.7 nm). By using pyridine vapor as a probe molecule to evaluate the active sites in the amorphous silica, we found that it has relatively strong Brønsted and Lewis acidic centers that do not desorb pyridine, even upon evacuation at 400 °C. The acidity of this new silica material was confirmed through representative two catalytic reactions: ring-opening reaction and Friedel-Crafts-type reaction, both of which are known to require acid catalysts.
赭毛菌鞘网状表层中 Fe、O 和 C 的结构和空间关联
影响因子：
4.4
作者：
T. Suzuki;H. Hashimoto;H. Ishihara;T. Kasai;H. Kunoh;J. Takada
通讯作者：
J. Takada
影响因子：
15
作者：
Iwamoto, M;Tanaka, Y;Namba, S
通讯作者：
Namba, S