Meaningful comparison of photocatalytic properties of {001} and {101} faceted anatase TiO2 nanocrystals

• Published in: Science bulletin (Beijing) Vol. 61; no. 13; pp. 1003 - 1012
• Main Authors: Lu, Yang, Zang, Yipeng, Zhang, Haimin, Zhang, Yunxia, Wang, Guozhong, Zhao, Huijun
• Format: Journal Article
• Language: English
• Published: Beijing Elsevier B.V 01.07.2016; Science China Press
• Subjects: adsorption; Anatase TiO2; Chemistry/Food Science; Crystal facet; Earth Sciences; Engineering; Humanities and Social Sciences; Life Sciences; multidisciplinary; nanocrystals; oxidation; Photocatalysis; photocatalysts; phthalic acid; Physics; renewable energy sources; Science; Science (multidisciplinary); Structure–activity relationships; TiO2光催化剂; TiO2纳米晶; titanium dioxide; 二氧化钛纳米晶; 催化氧化活性; 光催化活性; 光催化特性; 单分子层吸附; 锐钛矿型; Crystal facet; Anatase TiO2; Structure–activity relationships; Photocatalysis; 晶面; Anatase TiO; 锐钛矿二氧化钛; 光催化; 构效关系
• ISSN: 2095-9273; 2095-9281
• DOI: 10.1007/s11434-016-1109-8

The facet-dependent photocatalytic performance of TiO2 nanocrystals has been extensively investigated due to their promising applications in renewable energy and environmental fields. However, the intrinsic distinction in the photocatalytic oxidation activities between the {001 } and {101} facets of anatase TiO2 nanocrystals is still unclear and under debate. In this work, a simple photo- electrochemical method was employed to meaningfully quantify the intrinsic photocatalytic activities of {001 } and { 101 } faceted TiO2 nanocrystal photoanodes. The effective surface areas of photoanodes with different facets were measured based on the monolayer adsorption of phthalic acid on TiO2 photoanode surface by an ex situ photoelectrochemical method, which were used to normalize the photocurrents obtained from different faceted photoanodes for meaningful comparison of their photocatalytic activities. The results demonstrated that the { 001 } facets of anatase TiO2 nanocrystals exhibited much better photo- catalytic activity than that of { 101 } facets of anatase TiO2 nanocrystals toward photocatalytic oxidation of water and organic compounds with different functional groups （e.g., -OH, -CHO, -COOH）. Furthermore, the instantaneous kinetic constants of photocatalytic oxidation of pre-adsor- bates on {001} faceted anatase TiO2 photoanode are obviously greater than those obtained at {101} faceted anatase TiO2 photoanode, further verifying the higher photocatalytic activity of {001} facets of anatase TiO2. This work provided a facile photoelectrochemical method to quantitatively determine the photocatalytic oxidation activity of specific exposed crystal facets of a photocata- lyst, which would be helpful to uncover and meaningfully compare the intrinsic photocatalytic activities of different exposed crystal facets of a photocatalyst.