Hierarchical TiO2 Microspheres: Synergetic Effect of {001} and {101} Facets for Enhanced Photocatalytic Activity

• Published in: Chemistry : a European journal Vol. 17; no. 52; pp. 15032 - 15038
• Main Authors: Zheng, Zhaoke, Huang, Baibiao, Lu, Jibao, Qin, Xiaoyan, Zhang, Xiaoyang, Dai, Ying
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 23.12.2011; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Subjects: Chemistry; nanostructures; Photocatalysis; photocatalysts; reactive facets; Scanning electron microscopy; surface chemistry; titanium dioxide
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201101466

Well‐faceted nanocrystals of anatase TiO2 with specific reactive facets have attracted extraordinary research interest due to their many intrinsic shape‐dependent properties. In this work, hierarchical TiO2 microspheres consisting of anatase nanosheets or decahedrons were synthesized by means of a facile hydrothermal technique; meanwhile, the percentage of {001} facets can be tuned from 82 to 45 %. Importantly, by investigating the photo‐oxidation reactions for .OH radical generation and photoreduction reactions for hydrogen evolution, the TiO2 microspheres consisting of nano‐decahedrons with 45 % {001} facets show superior photoreactivity (more than 4.8‐times) compared to the nanosheets with 82 % {001} facets. By analyzing the results of scanning electron microscopy (SEM), photoluminescence (PL) and first‐principles density functional theory (DFT) calculations, a model of charge separation between the well‐formed {001} and {101} facets is proposed, and the enhanced photocatalytic efficiency is largely attributed to the efficient separation of photogenerated charges among the crystal facets co‐exposed. Makes good face: A facile strategy was developed to synthesize hierarchical TiO2 microspheres consisting of anatase nanosheets or decahedrons. Owing to the synergetic effect between well‐formed {001} and {101} facets, the TiO2 microspheres consisting of nano‐decahedrons with 45 % {001} facets show superior photoreactivity (more than 4.8‐times) compared to the nanosheets with 82 % {001} facets (see picture).