Application of EPR Spectroscopy in TiO2 and Nb2O5 Photocatalysis

Catalysts

Amer Hakki¹  Barbara Nascimento Nunes²  Osama Al-Madanat²  Detlef W. Bahnemann²  Yamen AlSalka³  Mariano Curti⁴  Antonio Otavio T. Patrocinio⁵ 

[1] Center for Industrial Process Technology, Department of Chemical Engineering, KU Leuven, Agoralaan Building B, 3590 Diepenbeek, Belgium;Institut für Technische Chemie, Leibniz Universität Hannover, Callinstr. 3, 30167 Hannover, Germany;Institute für Nanophotonik Göttingen e.V., Hans-Adolf-Krebs-Weg 1, 37077 Göttingen, Germany;Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology (BIST), Av. Països Catalans, 16, 43007 Tarragona, Spain;Laboratory of Photochemistry and Materials Science, Institute of Chemistry, Federal University of Uberlandia, Uberlandia 38400-902, Brazil;

关键词: EPR;    TiO₂;    Nb₂O₅;    spin trapping;    mechanistic studies;   

DOI  :  10.3390/catal11121514

来源: DOAJ

【 摘 要 】

The interaction of light with semiconducting materials becomes the center of a wide range of technologies, such as photocatalysis. This technology has recently attracted increasing attention due to its prospective uses in green energy and environmental remediation. The characterization of the electronic structure of the semiconductors is essential to a deep understanding of the photocatalytic process since they influence and govern the photocatalytic activity by the formation of reactive radical species. Electron paramagnetic resonance (EPR) spectroscopy is a unique analytical tool that can be employed to monitor the photoinduced phenomena occurring in the solid and liquid phases and provides precise insights into the dynamic and reactivity of the photocatalyst under different experimental conditions. This review focus on the application of EPR in the observation of paramagnetic centers formed upon irradiation of titanium dioxide and niobium oxide photocatalysts. TiO₂ and Nb₂O₅ are very well-known semiconductors that have been widely used for photocatalytic applications. A large number of experimental results on both materials offer a reliable platform to illustrate the contribution of the EPR studies on heterogeneous photocatalysis, particularly in monitoring the photogenerated charge carriers, trap states, and surface charge transfer steps. A detailed overview of EPR-spin trapping techniques in mechanistic studies to follow the nature of the photogenerated species in suspension during the photocatalytic process is presented. The role of the electron donors or the electron acceptors and their effect on the photocatalytic process in the solid or the liquid phase are highlighted.

【 授权许可】

Unknown