Beijing National Laboratory for Molecular Sciences, College of Chemistry, Peking University, Beijing 100871, People's Republic of China.
J Am Chem Soc. 2011 Feb 2;133(4):933-40. doi: 10.1021/ja108205q. Epub 2010 Dec 10.
Unique spindle-shaped nanoporous anatase TiO(2) mesocrystals with a single-crystal-like structure and tunable sizes were successfully fabricated on a large scale through mesoscale assembly in the tetrabutyl titanate-acetic acid system without any additives under solvothermal conditions. A complex mesoscale assembly process involving slow release of soluble species from metastable solid precursors for the continuous formation of nascent anatase nanocrystals, oriented aggregation of tiny anatase nanocrystals, and entrapment of in situ produced butyl acetate as a porogen was put forward for the formation of the anatase mesocrystals. It was revealed that the acetic acid molecules played multiple key roles during the nonhydrolytic processing of the [001]-oriented, single-crystal-like anatase mesocrystals. The obtained nanoporous anatase mesocrystals exhibited remarkable crystalline-phase stability (i.e., the pure phase of anatase can be retained after being annealed at 900 °C) and improved performance as anode materials for lithium ion batteries, which could be largely attributed to the intrinsic single-crystal-like nature as well as high porosity of the nanoporous mesocrystals.
通过在四丁醇钛-乙酸体系中在溶剂热条件下无任何添加剂进行介观组装，成功地大规模制备了具有单晶类似结构和可调节尺寸的独特纺锤形介孔锐钛矿 TiO2 mesocrystals。提出了一种复杂的介观组装过程，涉及从亚稳固体前体中缓慢释放可溶性物质以连续形成初生锐钛矿纳米晶、小锐钛矿纳米晶的定向聚集以及原位生成的乙酸丁酯作为致孔剂的捕获，以形成锐钛矿 mesocrystals。结果表明，在 [001] 取向的单晶类似锐钛矿 mesocrystals 的非水解处理过程中，乙酸分子发挥了多种关键作用。所得的纳米多孔锐钛矿 mesocrystals 表现出显著的晶相稳定性（即，在 900°C 下退火后仍能保持锐钛矿的纯相）和作为锂离子电池阳极材料的改进性能，这主要归因于纳米多孔 mesocrystals 的固有单晶类似性质和高孔隙率。
