School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, 430070, China.
Sci Rep. 2014 Sep 9;4:6298. doi: 10.1038/srep06298.
We successfully synthesized uniform Bi12GeO20 microspheres and microtetrahedrons enclosed by four {111} facets using a controlled hydrothermal method for the first time. The photocatalytic activity of these regular-shaped products was further investigated by the degradation of RhB and gaseous formaldehyde under visible light irradiation (λ>420 nm). The Bi12GeO20 microtetrahedrons (s) exhibited enhanced photocatalytic activity and stability which is closely related to the high capacity of exposed {111} facets for uptake of O2. The formation mechanism studies indicate that the Bi12GeO20 seeds were directed to grow into truncated microcubes, truncated microtetrahedrons, and then microtetrahedrons when the NaOH concentration was 5 M. The same batch of seeds only evolved into microspheres when the NaOH concentration was switched to 3 M. The difference in Bi12GeO20 morphology could be attributed to the rates of both crystal nucleation and crystal growth.
我们首次成功地使用可控水热法合成了由四个 {111} 面封闭的均匀 Bi12GeO20 微球和微四面体。通过在可见光照射下（λ>420nm）降解 RhB 和气态甲醛，进一步研究了这些规则形状产物的光催化活性。Bi12GeO20 微四面体（s）表现出增强的光催化活性和稳定性，这与暴露的 {111} 面具有高容量吸收 O2 的能力密切相关。形成机制研究表明，当 NaOH 浓度为 5M 时，Bi12GeO20 种子定向生长成截角微立方、截角微四面体，然后生长成微四面体。当 NaOH 浓度切换到 3M 时，同一批种子仅演变成微球。Bi12GeO20 形态的差异可归因于晶体成核和晶体生长的速率。
