Du Yi-en, Du Dejian, Feng Qi, Yang Xiaojing
†Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University, Beijing, 100875, China.
‡Department of Advanced Materials Science, Faculty of Engineering, Kagawa University, 2217-20 Hayashi-cho, Takamatsu-shi, 761-0396, Japan.
ACS Appl Mater Interfaces. 2015 Apr 22;7(15):7995-8004. doi: 10.1021/acsami.5b00227. Epub 2015 Apr 13.
{010}-Facet-exposed anatase TiO2 crystals exhibit the highest photoreactivity among the exposed facets. To obtain a higher exposure rate of this facet, the work investigated the transformation of the nanosheets with cavities within the layers derived from a rock-salt-structured Li2TiO3 precursor. All the lithium ions were extracted from the precursor by H+/Li+ ion exchange in HCl aqueous solutions, and after tetramethylammonium ions were intercalated, the precursor can delaminated into the nanosheets. The [TiO3]2- nanosheets were hydrothermally treated under different temperatures and pH values. The results showed that the anatase phase was formed in a wider range of pH and temperature, compared with using nanoribbons of [Ti4O9]2- and nanosheets of [Ti1.73O4]1.07-. At low pH, [111]-faceted nanorod-shaped anatase nanocrystals were formed preferentially, and the nanocrystals preferentially grow along the [001] direction with the increase of solution pH, leading to a large percentage of {010} facets on their surface. The photocatalytic activity increases with the increase of exposure rate of {010} facets.
{010}面暴露的锐钛矿型TiO₂晶体在暴露的晶面中表现出最高的光反应活性。为了获得该晶面更高的暴露率，该研究工作考察了由岩盐结构的Li₂TiO₃前驱体衍生而来的层内有空腔的纳米片的转变情况。通过在HCl水溶液中进行H⁺/Li⁺离子交换从前驱体中提取出所有锂离子，在插入四甲基铵离子后，前驱体可剥离成纳米片。对[TiO₃]²⁻纳米片在不同温度和pH值下进行水热处理。结果表明，与使用[Ti₄O₉]²⁻纳米带和[Ti₁.₇₃O₄]¹.⁰⁷⁻纳米片相比，在更宽的pH值和温度范围内形成了锐钛矿相。在低pH值下，优先形成[111]面的纳米棒状锐钛矿纳米晶体，随着溶液pH值的增加，纳米晶体优先沿[001]方向生长，导致其表面有很大比例的{010}面。光催化活性随着{010}面暴露率的增加而提高。
