Visible light superoxide radical anion generation by tetra(4-carboxyphenyl)porphyrin/TiO2: EPR characterization

Díaz‐Uribe, Carlos; Daza, Martha C.; Martı́nez, Fernando; Páez‐Mozo, Edgar A.; Guedes, Carmen Luı́sa Barbosa; Mauro, Eduardo Di

doi:10.1016/j.jphotochem.2010.08.013

Cited by 109 publications

(44 citation statements)

References 51 publications

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“…Thus, it is reasonable to assume that the small signals arise from superoxide formed during the loading and unloading of the autoclaves where some illumination from the ambient cannot be avoided. In contrast to P25, illumination of CsPbBr 3 /P25 with visible light leads to the evolution of a strong ESR signal, in which only the three hyperfine components of nitrogen are visible, resulting from the ring‐opening of the DMPO–superoxide adduct . Owing to the absence of any further hyperfine structure of trapped species, the original radical is devoid of protons, which strongly supports the formation of superoxide radicals under visible‐light illumination.…”

Section: Figurementioning

confidence: 89%

A CsPbBr₃/TiO₂ Composite for Visible‐Light‐Driven Photocatalytic Benzyl Alcohol Oxidation

2018

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Halide perovskites have attracted great attention in the fields of photovoltaics, LEDs, lasers, and most recently photocatalysis, owing to their unique optoelectronic properties. The all-inorganic halide perovskite CsPbBr /TiO composite material catalyzes selective benzyl alcohol oxidation to benzaldehyde under visible-light illumination. The catalyst, which is prepared by a facile wet-impregnation method, shows very good selectivity towards benzaldehyde (>99 % at 50 % conversion). Action spectra and electron spin resonance (ESR) studies reveal that photoexcited electrons formed within CsPbBr upon visible-light illumination take part in the reaction via reduction of oxygen to form superoxide radicals. The detailed post-catalysis characterization by UV/Vis and X-ray photoelectron spectroscopy, X-ray diffraction, and high-angle annular dark-field scanning transmission electron microscopy studies further demonstrated the good stability of CsPbBr in terms of morphology and crystal structure under the reaction conditions. This study sheds light on promising new photocatalytic applications of halide perovskites.

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Section: Figurementioning

confidence: 89%

A CsPbBr₃/TiO₂ Composite for Visible‐Light‐Driven Photocatalytic Benzyl Alcohol Oxidation

2018

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“…The symmetric vibration mode of À COO À on TCPP near 1400 cm À 1 shifted to 1388 cm À 1 in all the hybrids, and became intensified with the increase of TCPP doping content. [19][20] Moreover, the CÀ O stretching vibration and C=O vibration peak at 1225, 1277 cm À 1 and 1692 cm À 1 vanished upon embedded on CeO 2 NTs, indicating that the carboxylic acid groups of TCPP chemically bonded with hydroxyl groups on the surface of CeO 2 instead of physical absorption. Such tight coupling is beneficial to both 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 the stability of hybrids and the electronic communication between the composition.…”

Section: Synthesis and Structural Characterizationmentioning

confidence: 98%

Enzyme‐Like Catalytic Activity of Porphyrin‐Functionalized Ceria Nanotubes for Water Oxidation

Meng

Chen

et al. 2019

ChemPlusChem

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Artificial enzymes have broad applications in catalysis and can be used to help understand catalytic mechanisms. Nanoceria has various enzyme‐mimetic properties that depend on the relative content of Ce3+ and Ce4+. In this context, CeO2 nanotubes was investigated as catalase mimics for water oxidation. The photosensitizer 5,10,15,20‐meso‐tetra(4‐carboxyphenyl) porphyrin (TCPP) was facilely embedded in CeO2 nanotubes (TCPP@CeO2 NTs), and photoinduced charge transfer was shown to occur between the strongly coupled TCPP and CeO2, which leads to effective charge separation and charge redistribution within the hybrids. As a consequence, formation of H2O2, a competing process in water oxidation and a key factor that affects the oxidative stability of photoelectrodes, was effectively inhibited on TCPP@CeO2 NTs. These findings show that enzyme mimics can be used for the selective generation of reactive oxygen species, and therefore to control the kinetics of water oxidation.

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“…However,t he DMPO-O 2 À C EPR signalwas clear under visible-light illumination, providing directp roof that O 2 À C,a st he most important active oxygen species, exists in the photo-oxidationo fD HA, which is consistentwith the resultsreported by other authors. [46][47][48][49]…”

Section: Epr Spin Trappingmentioning

confidence: 99%

Visible‐Light‐Triggered Quantitative Oxidation of 9,10‐Dihydroanthracene to Anthraquinone by O₂ under Mild Conditions

Jiang

Chen

et al. 2020

ChemSusChem

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The development of mild and efficient processes for the selective oxygenation of organic compounds by molecular oxygen (O2) is key for the synthesis of oxygenates. This paper discloses an atom‐efficient synthesis protocol for the photo‐oxygenation of 9,10‐dihydroanthracene (DHA) by O2 to anthraquinone (AQ), which could achieve quantitative AQ yield (100 %) without any extra catalysts or additives under ambient temperature and pressure. A yield of 86.4 % AQ was obtained even in an air atmosphere. Furthermore, this protocol showed good compatibility for the photo‐oxidation of several other compounds with similar structures to DHA. From a series of control experiments, free‐radical quenching, and electron paramagnetic resonance spin‐trapping results, the photo‐oxygenation of DHA was probably initiated by its photoexcited state DHA*, and the latter could activate O2 to a superoxide anion radical (O2.−) through the transfer of its electron. Subsequently, this photo‐oxidation was gradually dominated by the oxygenated product AQ as an active photocatalyst obtained from the oxidation of DHA by O2.−, and was accelerated with the rapid accumulation of AQ. The present photo‐oxidation protocol is a good example of selective oxygenation based on the photoexcited substrate self‐activated O2, which complies well with green chemistry ideals.

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Visible light superoxide radical anion generation by tetra(4-carboxyphenyl)porphyrin/TiO2: EPR characterization

Cited by 109 publications

References 51 publications

A CsPbBr₃/TiO₂ Composite for Visible‐Light‐Driven Photocatalytic Benzyl Alcohol Oxidation

A CsPbBr₃/TiO₂ Composite for Visible‐Light‐Driven Photocatalytic Benzyl Alcohol Oxidation

Enzyme‐Like Catalytic Activity of Porphyrin‐Functionalized Ceria Nanotubes for Water Oxidation

Visible‐Light‐Triggered Quantitative Oxidation of 9,10‐Dihydroanthracene to Anthraquinone by O₂ under Mild Conditions

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Visible light superoxide radical anion generation by tetra(4-carboxyphenyl)porphyrin/TiO2: EPR characterization

Cited by 109 publications

References 51 publications

A CsPbBr3/TiO2 Composite for Visible‐Light‐Driven Photocatalytic Benzyl Alcohol Oxidation

A CsPbBr3/TiO2 Composite for Visible‐Light‐Driven Photocatalytic Benzyl Alcohol Oxidation

Enzyme‐Like Catalytic Activity of Porphyrin‐Functionalized Ceria Nanotubes for Water Oxidation

Visible‐Light‐Triggered Quantitative Oxidation of 9,10‐Dihydroanthracene to Anthraquinone by O2 under Mild Conditions

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A CsPbBr₃/TiO₂ Composite for Visible‐Light‐Driven Photocatalytic Benzyl Alcohol Oxidation

A CsPbBr₃/TiO₂ Composite for Visible‐Light‐Driven Photocatalytic Benzyl Alcohol Oxidation

Visible‐Light‐Triggered Quantitative Oxidation of 9,10‐Dihydroanthracene to Anthraquinone by O₂ under Mild Conditions