Hierarchical FeTiO 3 –TiO 2 hollow spheres for efficient simulated sunlight-driven water oxidation

• Published in: Nanoscale 2015, Vol.7 (38), p.15924-15934
• Main Authors: Han, Taoran, Chen, Yajie, Tian, Guohui, Wang, Jian-Qiang, Ren, Zhiyu, Zhou, Wei, Fu, Honggang
• Format: Article
• Language: English
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/C5NR05242D

Oxygen generation is the key step for the photocatalytic overall water splitting and considered to be kinetically more challenging than hydrogen generation. Here, an effective water oxidation catalyst of hierarchical FeTiO 3 –TiO 2 hollow spheres are prepared via a two-step sequential solvothermal processes and followed by thermal treatment. The existence of an effective heterointerface and built-in electric field in the surface space charge region in FeTiO 3 –TiO 2 hollow spheres plays a positive role in promoting the separation of photoinduced electron–hole pairs. Surface photovoltage, transient-state photovoltage, fluorescence and electrochemical characterization are used to investigate the transfer process of photoinduced charge carriers. The photogenerated charge carriers in the hierarchical FeTiO 3 –TiO 2 hollow spheres with a proper molar ratio display much higher separation efficiency and longer lifetime than those in the FeTiO 3 alone. Moreover, it is suggested that the hierarchical porous hollow structure can contribute to the enhancement of light utilization, surface active sites and material transportation through the framework walls. This specific synergy significantly contributes to the remarkable improvement of the photocatalytic water oxidation activity of the hierarchical FeTiO 3 –TiO 2 hollow spheres under simulated sunlight (AM1.5).