Graduate School of Chemical Science and Engineering, Hokkaido University, Sapporo 060-0814, Japan.
ACS Appl Mater Interfaces. 2013 Feb;5(4):1348-54. doi: 10.1021/am302631b. Epub 2013 Feb 11.
We succeed in preparation of anatase TiO₂ single crystals with marked photocatalytic activity via a facile and effective method. This TiO₂ is composed of TiO₂ ultrathin nanosheets (2 nm in thickness) with 95% of exposed {100} facet, which is considered to be the active facet for photocatalytic reaction. This percentage (95%) is the highest among previously reported {100} facet exposed anatase TiO₂. More importantly, due to this high ratio, our developed TiO₂ nanosheets showed marked photocatalytic activity, about 5 times higher activity in both H₂ evolution and CO₂ reduction than the reference sample, TiO₂ cuboids with 53% of exposed {100} facet. For the TiO₂ nanosheets, both the higher percentage of exposed {100} facets and larger surface area can offer more surface active sites in the photocatalytic reaction. On the other hand, the superior electronic band structure which results from the higher percentage of {100} facet is also beneficial for the higher activity. This study exemplifies that the facet engineering of semiconductors is one of the most effective strategies to achieve advanced properties over photofunctional materials for solar energy conversion.
我们成功地通过一种简单有效的方法制备了具有显著光催化活性的锐钛矿 TiO₂单晶。这种 TiO₂由厚度为 2nm 的 TiO₂超薄纳米片组成，其中 95%暴露的是{100}晶面，这被认为是光催化反应的活性晶面。这个比例（95%）在之前报道的暴露{100}晶面的锐钛矿 TiO₂中是最高的。更重要的是，由于这个高比例，我们开发的 TiO₂纳米片表现出显著的光催化活性，在 H₂ 演化和 CO₂还原方面的活性比参考样品 TiO₂长方体（暴露{100}晶面的比例为 53%）高约 5 倍。对于 TiO₂纳米片来说，暴露的{100}晶面的更高比例和更大的表面积都可以在光催化反应中提供更多的表面活性位点。另一方面，由于{100}晶面比例较高而导致的优越的电子能带结构也有利于更高的活性。这项研究证明了半导体的晶面工程是实现太阳能转换用光功能材料的先进性能的最有效策略之一。
