1,4-Benzoquinone and 1,4-hydroquinone based determination of electron and superoxide radical formed in heterogeneous photocatalytic systems

Fónagy, Orsolya; Szabó-Bárdos, Erzsébet; Horváth, Ottó

doi:10.1016/j.jphotochem.2020.113057

Cited by 145 publications

(63 citation statements)

References 89 publications

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“…These results strongly suggest the formation of superoxide upon treating the catalyst with O 2 . Furthermore, addition of superoxide quencher p-quinone [72][73][74] to the Au/PyEt-MSN catalysed reaction of N-methyl pyrrolidine also led to a drop in conversion (6 h TON of 20) under our standard conditions, further suggesting that these reactive oxygen species take part in the process. We note that while the electron-deficient Au/MP-MSN is still able to mediate the reaction, its activity does not change upon flowing the system with N 2 instead of O 2 (6 h TON is 6 regardless of flowing with N 2 or O 2 ).…”

Section: Effects Of Surface Groups On Catalytic Activitymentioning

confidence: 74%

Surface ligands enhance the catalytic activity of supported Au nanoparticles for the aerobic α-oxidation of amines to amides

Chatterjee

Wang

Manzano

et al. 2022

Catal. Sci. Technol.

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Section: Effects Of Surface Groups On Catalytic Activitymentioning

confidence: 74%

Surface ligands enhance the catalytic activity of supported Au nanoparticles for the aerobic α-oxidation of amines to amides

Chatterjee

Wang

Manzano

et al. 2022

Catal. Sci. Technol.

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“…Besides • OH formation efficiency, the possibility of direct charge transfer and efficiency of e CB − was also studied and compared. Fónagy et al demonstrated that 1,4-benzoquinone (1,4-BQ) can be used as a direct e CB − scavenger under anoxic atmosphere, and the amount of the formed 1,4-H 2 Q is proportional to that of e CB − generated during the excitation of a photocatalyst [ 93 ]. Thus, we used the transformation rate of 1,4-benzoquinone (1,4-BQ) and the formation rate of 1,4-H 2 Q to investigate and compare the formation rate of photogenerated e CB − The backward reaction is also possible; reaction between 1,4-H 2 Q and h VB + (Equation (2)) results in 1,4-BQ [ 93 , 94 ].…”

Section: Resultsmentioning

confidence: 99%

“…Fónagy et al demonstrated that 1,4-benzoquinone (1,4-BQ) can be used as a direct e CB − scavenger under anoxic atmosphere, and the amount of the formed 1,4-H 2 Q is proportional to that of e CB − generated during the excitation of a photocatalyst [ 93 ]. Thus, we used the transformation rate of 1,4-benzoquinone (1,4-BQ) and the formation rate of 1,4-H 2 Q to investigate and compare the formation rate of photogenerated e CB − The backward reaction is also possible; reaction between 1,4-H 2 Q and h VB + (Equation (2)) results in 1,4-BQ [ 93 , 94 ]. 1,4-BQ + 2 e CB − + 2 H + → 1,4-H 2 Q 1,4-H 2 Q + 2 h VB + → 1,4-BQ + 2 H + h VB + + OH − /H 2 O → • OH 1,4-BQ + • OH → Products 1,4-H 2 Q + • OH → Products …”

Section: Resultsmentioning

confidence: 99%

Wavelength Dependence of the Transformation Mechanism of Sulfonamides Using Different LED Light Sources and TiO2 and ZnO Photocatalysts

et al. 2021

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The comparison of the efficiency of the commercially available photocatalysts, TiO2 and ZnO, irradiated with 365 nm and 398 nm light, is presented for the removal of two antibiotics, sulfamethazine (SMT) and sulfamethoxypyridazine (SMP). The •OH formation rate was compared using coumarin, and higher efficiency was proved for TiO2 than ZnO, while for 1,4-benzoquinone in O2-free suspensions, the higher contribution of the photogenerated electrons to the conversion was observed for ZnO than TiO2, especially at 398 nm irradiation. An extremely fast transformation and high quantum yield of SMP in the TiO2/LED398nm process were observed. The transformation was fast in both O2 containing and O2-free suspensions and takes place via desulfonation, while in other cases, mainly hydroxylated products form. The effect of reaction parameters (methanol, dissolved O2 content, HCO3− and Cl−) confirmed that a quite rarely observed energy transfer between the excited state P25 and SMP might be responsible for this unique behavior. In our opinion, these results highlight that “non-conventional” mechanisms could occur even in the case of the well-known TiO2 photocatalyst, and the effect of wavelength is also worth investigating.

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“…In order to verify this hypothesis, 1,4-benzoquinone (BQ) was introduced into the system, which had obvious quenching effect on O 2 − •. 63 As shown in Fig. 9(b), the removal rate of RhB was reduced by 35% after the introduction of BQ.…”

Section: Durability Testmentioning

confidence: 95%

Bimetal oxalate‐derived synthesis of laponite‐decorated CoFe₂O₄ porous nanostructures for activation of peroxymonopersulfate towards degradation of rhodamine B

Wei

Song

Liu

et al. 2021

J of Chemical Tech & Biotech

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BACKGROUND: Advanced oxidation processes based on sulfate radical have been widely employed for oxidation degradation of organic contaminants. Catalytic activation of peroxymonopersulfate (PMS) with transition metal oxides holds great promise for the generation of sulfate radical. In this work, laponite-decorated CoFe 2 O 4 porous nanostructures have been prepared through the thermal decomposition of laponite/oxalates, and evaluated as a magnetic catalyst to activate PMS for the oxidation of rhodamine B (RhB).RESULTS: The decoration of porous CoFe 2 O 4 microparticles with laponite was evidenced because of the presence of the vibration mode of Si O (at 1359 cm −1 ) in Fourier transform infrared spectra and the uniform distribution of Si and Mg elements from elemental mapping images. Decorating with laponite also resulted in an increase in amount of surface hydroxyl oxygen species, which facilitated the formation of Co OH complex for PMS activation. Furthermore, the enhanced activation of PMS with laponite-decorated CoFe 2 O 4 resulted in a faster removal (98.04%) of RhB as compared to undecorated CoFe 2 O 4 (79.62%) within 56 min. Meanwhile, the rate constant increased from 0.0288 (CoFe 2 O 4 ) to 0.0679 min −1 (laponite-decorated CoFe 2 O 4 ). The degradation rate of RhB progressively increased with reaction temperature and catalyst dosage. Scavenging and electron paramagnetic resonance tests manifested that the sulfate and superoxide radicals served as the major active species for the oxidation of RhB molecules. CONCLUSION:The above results demonstrated positive effects of laponite on the textural property, surface chemical states and catalytic activity of porous CoFe 2 O 4 microparticles. This study provides an insight into the promising role of laponite as an additive in improving PMS activation.

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1,4-Benzoquinone and 1,4-hydroquinone based determination of electron and superoxide radical formed in heterogeneous photocatalytic systems

Cited by 145 publications

References 89 publications

Surface ligands enhance the catalytic activity of supported Au nanoparticles for the aerobic α-oxidation of amines to amides

Surface ligands enhance the catalytic activity of supported Au nanoparticles for the aerobic α-oxidation of amines to amides

Wavelength Dependence of the Transformation Mechanism of Sulfonamides Using Different LED Light Sources and TiO2 and ZnO Photocatalysts

Bimetal oxalate‐derived synthesis of laponite‐decorated CoFe₂O₄ porous nanostructures for activation of peroxymonopersulfate towards degradation of rhodamine B

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1,4-Benzoquinone and 1,4-hydroquinone based determination of electron and superoxide radical formed in heterogeneous photocatalytic systems

Cited by 145 publications

References 89 publications

Surface ligands enhance the catalytic activity of supported Au nanoparticles for the aerobic α-oxidation of amines to amides

Surface ligands enhance the catalytic activity of supported Au nanoparticles for the aerobic α-oxidation of amines to amides

Wavelength Dependence of the Transformation Mechanism of Sulfonamides Using Different LED Light Sources and TiO2 and ZnO Photocatalysts

Bimetal oxalate‐derived synthesis of laponite‐decorated CoFe2O4 porous nanostructures for activation of peroxymonopersulfate towards degradation of rhodamine B

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Bimetal oxalate‐derived synthesis of laponite‐decorated CoFe₂O₄ porous nanostructures for activation of peroxymonopersulfate towards degradation of rhodamine B