Probing paramagnetic species in titania-based heterogeneous photocatalysis by electron spin resonance (ESR) spectroscopy—A mini review

Wang, Zhaohui; Ma, Wanhong; Chen, Chuncheng; Ji, Hongwei; Zhao, Jincai

doi:10.1016/j.cej.2010.12.002

Cited by 297 publications

(117 citation statements)

References 92 publications

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“…The ESR signals were observed after light irradiation for 5 and 10 min. The observed sextet ESR signal with an intensity ratio of 1:1:1:1:1:1 could be ascribed to the presence of DMPO-O 2 −• [29,30,51]. This observation confirms the formation of O 2 −• in the presence of either pure BFO or 1.0 wt% Pt/BFO photocatalysts during light irradiation though the corresponding intensities were different.…”

Section: Proposed Photocatalytic Mechanismsupporting

confidence: 85%

Synthesis of Pt/BiFeO3 heterostructured photocatalysts for highly efficient visible-light photocatalytic performances

Niu

Chen

Qin

et al. 2015

Solar Energy Materials and Solar Cells

132

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Section: Proposed Photocatalytic Mechanismsupporting

confidence: 85%

Synthesis of Pt/BiFeO3 heterostructured photocatalysts for highly efficient visible-light photocatalytic performances

Niu

Chen

Qin

et al. 2015

Solar Energy Materials and Solar Cells

132

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“…The method is based on the reaction of a diamagnetic spin trapping agent with transient radical, forming more stable paramagnetic spin-adduct. DMPO is the most convenient spin trap applied in photochemical systems due to its low photoactivity, wide potential window, and solubility in polar and non-polar solvents [25,[47][48][49]. The ability of the studied photocatalysts to generate hydroxyl radical upon irradiation was tested in aerated aqueous suspensions in the presence of DMPO.…”

Section: Resultsmentioning

confidence: 99%

EPR Investigations of G-C3N4/TiO2 Nanocomposites

et al. 2018

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Abstract:The g-C 3 N 4 /TiO 2 nanopowders prepared by the annealing of melamine and TiO 2 P25 at 550 • C were investigated under dark and upon UV or visible-light photoactivation using X-and Q-band electron paramagnetic resonance (EPR) spectroscopy. The EPR spectra of powders monitored at room temperature and 100 K showed the impact of the initial loading ratio of melamine/TiO 2 on the character of paramagnetic centers observed. For the photocatalysts synthesized using a lower titania content, the paramagnetic signals characteristic for the g-C 3 N 4 /TiO 2 nanocomposites were already found before exposure. The samples annealed using the higher TiO 2 loading revealed the photoinduced generation of paramagnetic nitrogen bulk centers (g-tensor components g 1 = 2.005, g 2 = 2.004, g 3 = 2.003 and hyperfine couplings from the nitrogen A 1 = 0.23 mT, A 2 = 0.44 mT, A 3 = 3.23 mT) typical for N-doped TiO 2 . The ability of photocatalysts to generate reactive oxygen species (ROS) upon in situ UV or visible-light photoexcitation was tested in water or dimethyl sulfoxide by EPR spin trapping using 5,5-dimethyl 1-pyrroline N-oxide. The results obtained reflect the differences in photocatalyst nanostructures caused by the differing initial ratio of melamine/TiO 2 ; the photocatalyst prepared by the high-temperature treatment of melamine/TiO 2 wt. ratio of 1:3 revealed an adequate photoactivity in both spectral regions.

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“…• CH 2 COOH, CH 3 CO • , trapped electron in transition metals (because it localises in their d orbital), reactive oxygen species, bulk and surface non-metals, have been elucidated directly by EPR (Wang et al 2011) Recently, Fu et al (2006 carried out EPR measurements that gave the first direct evidence that the active species…”

Section: Paramagnetic Resonance Methodsmentioning

confidence: 98%

Mechanistic Principles of Photocatalytic Reaction

Gaya¹

2013

Heterogeneous Photocatalysis Using Inorganic Semiconductor Solids

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As developments in semiconductor photocatalysis flourish, profound success is being recorded in the elucidation of reactivity vis-à-vis mechanism. The mechanism of photocatalytic reactions lies between two limits. From viewpoint of photochemical kinetics, the reaction mechanism will be controlled by the properties of light and consequences of light absorption. However as mass transfer dominates, the process will be controlled by the non-catalytic diffusion mechanism. This chapter highlights both diffusion and photocatalytically controlled kinetics in semiconductor-based heterogeneous regimes. In the final place, some conventional analytical methods for validation of photocatalytic reaction mechanism are discussed.

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Probing paramagnetic species in titania-based heterogeneous photocatalysis by electron spin resonance (ESR) spectroscopy—A mini review

Cited by 297 publications

References 92 publications

Synthesis of Pt/BiFeO3 heterostructured photocatalysts for highly efficient visible-light photocatalytic performances

Synthesis of Pt/BiFeO3 heterostructured photocatalysts for highly efficient visible-light photocatalytic performances

EPR Investigations of G-C3N4/TiO2 Nanocomposites

Mechanistic Principles of Photocatalytic Reaction

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