title: Supersaturation-controlled shape evolution of α-Fe2O3 nanocrystals and their facet-dependent catalytic and sensing properties.
abstract: Surface engineering of crystals at nanoscale level by precisely and rationally exposing specific facets proved to be highly effective in enhancing the performance of inorganic functional nanocrystals. To do so, a comprehensive understanding of the growth mechanism was of great importance. By using hematite (α-Fe2O3) as an example, in this paper we demonstrated high effectiveness of controlling supersaturation of growth monomers in engineering the exposed facets of nanocrystals. Under surfactant-free hydrothermal conditions, a series of morphology evolution of α-Fe2O3 nanocrystals from {012} faceted pseudocubes to {113} faceted hexagonal bipyramids and {001} faceted nanoplates were successfully activated through concentration-, reaction time-, and solvent-dependent hydrolysis of ferric acetylacetonate. High supersaturation was eventually proven to be conducive to the formation of facets with high surface energy. Furthermore, the α-Fe2O3 nanocrystals enclosed with facets of high surface energy exhibited excellent catalytic activity and gas-sensing ability. The present work will deepen our understanding of thermodynamics and kinetic control over the morphology of nanocrystals as well as our understanding of surface-related performance of inorganic functional nanocrystals.
authors.affiliation: State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University , Xiamen 361005, China.
authors.forename: Junjie
authors.initials: J
authors.lastname: Ouyang
authors.forename: Jun
authors.initials: J
authors.lastname: Pei
authors.forename: Qin
authors.initials: Q
authors.lastname: Kuang
authors.forename: Zhaoxiong
authors.initials: Z
authors.lastname: Xie
authors.forename: Lansun
authors.initials: L
authors.lastname: Zheng