TY - JOUR

T1 - Application of EPR spectroscopy in TiO2 and Nb2O5 photocatalysis

AU - Al-Madanat, Osama

AU - Nunes, Barbara Nascimento

AU - Alsalka, Yamen

AU - Hakki, Amer

AU - Curti, Mariano

AU - Patrocinio, Antonio Otavio T.

AU - Bahnemann, Detlef W.

N1 - Funding Information: Funding: Financial support from the Katholischer Akademischer Ausländer-Dienst (KAAD) and Graduiertenakademie at Gottfried Wilhelm Leibniz Universität Hannover are gratefully acknowledged for providing scholarships for Osama Al-Madanat to perform his PhD. B.N.N. gratefully acknowledges the financial support from CAPES, Brazil, from the CAPES/DAAD/CNPQ (15/2017) program, grant number 88887.161403/2017-00. M.C. acknowledges the funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 801474 and from the State Research Agency/Spanish Ministry of Science and Innovation (AEI/MICINN) through the Severo Ochoa Excellence Accreditation CEX2019-000925-S. The studies performed in the laboratory “Photoactive nanocomposite materials” were supported by Saint-Petersburg State University (ID: 73032813).

PY - 2021/12

Y1 - 2021/12

N2 - 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.

AB - 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.

KW - EPR

KW - Mechanistic studies

KW - NbO

KW - Spin trapping

KW - TiO

UR - http://www.scopus.com/inward/record.url?scp=85121269936&partnerID=8YFLogxK

U2 - 10.3390/catal11121514

DO - 10.3390/catal11121514

M3 - Review article

AN - SCOPUS:85121269936

VL - 11

JO - CATALYSTS

JF - CATALYSTS

SN - 2073-4344

IS - 12

M1 - 1514

ER -