Fu Bing, Wu Zhijiao, Guo Kai, Piao Lingyu
CAS Center for Excellence in Nanoscience, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, P. R. China.
Nanoscale. 2021 May 13;13(18):8591-8599. doi: 10.1039/d1nr01544c.
Owing to their scientific and technological importance, the development of highly efficient photocatalytic water oxidation systems with rapid photogenerated charge separation and high surface catalytic activity is highly desirable for the storage and conversion of solar energy. A promising candidate is rutile phase titanium dioxide (TiO2), which has been widely studied over half a century. Specifically, oriented single-crystalline TiO2 surfaces with high oxidative reactivity would be most desirable, but achieving these structures has been limited by the availability of synthetic techniques. In this study, a facile and green synthetic approach was developed for the first time to synthesize rutile TiO2 single crystals with regulable reductive and oxidative facets. Glycolic acid (GA) and sodium fluoride (NaF) are used as the crucial and effective phase and facet controlling agents, respectively. The selective adsorption of F- ions on the facets of rutile TiO2 crystals not only plays a key role in driving the nucleation and preferential growth of the crystals with desired facets but also significantly affects their photocatalytic gas evolution reactivity. With heat treatment, the highly stable F--free rutile TiO2 single crystals with a high percentage of oxidative facets exhibit a superior photocatalytic gas evolution rate (≈116 μmol h-1 per 0.005 g catalyst), 8.5 times higher than that of previous F--containing samples.
由于其科学技术重要性，开发具有快速光生电荷分离和高表面催化活性的高效光催化水氧化系统对于太阳能的存储和转换非常必要。一种有前景的候选材料是金红石相二氧化钛（TiO₂），半个多世纪以来它一直受到广泛研究。具体而言，具有高氧化反应活性的定向单晶TiO₂表面是最理想的，但实现这些结构受到合成技术可用性的限制。在本研究中，首次开发了一种简便且绿色的合成方法来合成具有可调节还原面和氧化面的金红石TiO₂单晶。乙醇酸（GA）和氟化钠（NaF）分别用作关键且有效的相和晶面控制剂。F⁻离子在金红石TiO₂晶体晶面上的选择性吸附不仅在驱动具有所需晶面的晶体的成核和优先生长中起关键作用，而且还显著影响其光催化析气反应活性。经过热处理，具有高比例氧化面的高度稳定的无F⁻金红石TiO₂单晶表现出优异的光催化析气速率（每0.005 g催化剂约116 μmol h⁻¹），比之前含F⁻的样品高8.5倍。
