Online Quantification of O2·-and H2O2and Their Formation Kinetics in Ultraviolet (UV)-Irradiated Nano-TiO2Suspensions by Continuous Flow Chemiluminescence

王大彬,; 赵利霞,; 郭良宏,; 张辉,; 万斌,; 杨郁,

doi:10.6023/a15010036

Cited by 7 publications

(3 citation statements)

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“…The latter emitted strong CL when mixed with H 2 O 2 and K 5 Cu(HIO 6 ) 2 . The concentration of O 2 •– and ·OH were quantified according to the CL intensity. − …”

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confidence: 99%

Surface Bridge Hydroxyl-Mediated Promotion of Reactive Oxygen Species in Different Particle Size TiO₂ Suspensions

Zhao

Chen

et al. 2019

J. Phys. Chem. Lett.

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Reactive oxygen species (ROS) play an essential role in TiO 2 photocatalysis. They arise from the transfer of lightinitiated carriers to the TiO 2 surface and react with oxygen or water, in which the TiO 2 surface is crucial. However, how the TiO 2 surface affects ROS production is unclear. Herein, dynamic generation of ROS in suspensions of TiO 2 of different particle sizes was investigated under ultraviolet-light irradiation. It is surprising to find that more ROS were produced more quickly for 100−140 nm TiO 2 than for 20−60 nm TiO 2 . Further research suggested that ROS production was intrinsically correlated with the surface bridging hydroxyls per unit area. More bridging hydroxyls induced lower IEP and more negative charges on the TiO 2 surface, which favored the transfer of photogenerated carriers, resulting in the promotion of ROS and photocatalytic activity. This provided insight into designing high-efficiency photocatalysts to solve the problem of small particle sizes causing loss and blockage in wastewater treatment.

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“…The latter emitted strong CL when mixed with H 2 O 2 and K 5 Cu(HIO 6 ) 2 . The concentration of O 2 •– and ·OH were quantified according to the CL intensity. − …”

mentioning

confidence: 99%

Surface Bridge Hydroxyl-Mediated Promotion of Reactive Oxygen Species in Different Particle Size TiO₂ Suspensions

Zhao

Chen

et al. 2019

J. Phys. Chem. Lett.

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“…As we know, the CL intensity was usually affected by the buffer type and pH of the CL system, oxidant concentration, and pump speed, etc. , Therefore, these parameters were investigated systematically for the CFCL monitoring of TCBQ and OH-TrCBQ. TiO 2 /PCP suspension as shown in Figure was replaced by TCBQ or OH-TrCBQ standard solutions, and the xenon lamp was shut down.…”

Section: Resultsmentioning

confidence: 99%

“…Chemiluminescence (CL) is well suited for the detection of unstable intermediates, since the luminescence is instantly produced by a redox chemical reaction when CL reactants including intermediates and an oxidant are mixed, and light emission can be detected immediately by a photomultiplier tube (PMT) with ultralow background. − Therefore, CL is capable of following the dynamic process of unstable intermediates generation and transformation in photocatalysis. In the previous work, a CFCL was developed for the selective and online detection of O 2 •– , • OH, and H 2 O 2 generated during UV irradiation of nano-TiO 2 suspension with the advantages of high sensitivity and high selectivity. , However, no work was reported on tracking the dynamic process of highly toxic intermediates generation during the PCP photocatalytic degradation using CL.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Tracking of Highly Toxic Intermediates in Photocatalytic Degradation of Pentachlorophenol by Continuous Flow Chemiluminescence

Zhao

Wang

et al. 2018

Environ. Sci. Technol.

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Photocatalytic degradation is a powerful technique for the decomposition of pollutants. However, toxic intermediates might be generated which have become a great concern recently. In the present work, a continuous flow chemiluminescence (CFCL) method was developed for dynamic monitoring of toxic intermediates generated in the photocatalytic degradation of pentachlorophenol (PCP). Among the main intermediates, tetrachloro-1,4-benzoquinone (TCBQ) and trichlorohydroxy-1,4-benzoquinone (OH-TrCBQ) showed higher or similar toxicity to PCP. As both TCBQ and OH-TrCBQ can produce chemiluminescence (CL) in the presence of HO, a CFCL system was established for the dynamic tracking of the two toxic intermediates. A PCP/TiO suspension was irradiated in a photoreactor, pumped continuously into a detection cell, and mixed with HO to produce CL. The time-dependent CL response displayed two distinctive peaks at pH 7, which were attributed to the generation of OH-TrCBQ and TCBQ, respectively, by comparing with their changes measured by high-performance liquid chromatography (HPLC). Furthermore, the CL response curve of PCP/TiO suspension showed a pattern very similar to their bacteria inhibition. Therefore, the CFCL could be used as a simple and low-cost method for online monitoring of TCBQ and OH-TrCBQ to ensure complete removal of not only PCP but also highly toxic degradation intermediates.

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Metal‐free Semiconductor Photocatalysis for sp² C−H Functionalization with Molecular Oxygen

et al. 2018

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Designing metal‐free catalysts for solar energy conversion is a long‐standing challenge in semiconductor photoredox catalysis (SPC). With visible‐light‐responsive hexagonal boron carbon nitride (h‐BCN) as a non‐metal photocatalyst, this system affords C−H/N−H coupling products with broad substitution tolerance and high efficiency with molecular oxygen as the terminal oxidant. The catalyst exhibits remarkable performance for the selective C−H functionalization of electron‐rich arenes to C−N products (yields up to 95 %) and good stability (6 recycles). Both nitrogen heteroarenes and amine salts are competent coupling nucleophiles. Mechanically, the reactive oxygen species are superoxide anion radical (O2−.) and H2O2, which are proved by electron spin resonance (ESR) data, KI‐starch, and control experiments. In addition, kinetic isotope effect (KIE) experiments indicate that C−H bond cleavage is not involved in the rate limiting step. This semiconductor‐based photoredox system allows for C−H amination free of any metals, ligands, strong oxidants, and additives. It provides a complementary avenue to C−H functionalizations and enables synthetic applications efficiently in a sustainable manner.

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Online Quantification of O₂^·-and H₂O₂and Their Formation Kinetics in Ultraviolet (UV)-Irradiated Nano-TiO₂Suspensions by Continuous Flow Chemiluminescence

Cited by 7 publications

References 1 publication

Surface Bridge Hydroxyl-Mediated Promotion of Reactive Oxygen Species in Different Particle Size TiO₂ Suspensions

Surface Bridge Hydroxyl-Mediated Promotion of Reactive Oxygen Species in Different Particle Size TiO₂ Suspensions

Dynamic Tracking of Highly Toxic Intermediates in Photocatalytic Degradation of Pentachlorophenol by Continuous Flow Chemiluminescence

Metal‐free Semiconductor Photocatalysis for sp² C−H Functionalization with Molecular Oxygen

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Online Quantification of O2·-and H2O2and Their Formation Kinetics in Ultraviolet (UV)-Irradiated Nano-TiO2Suspensions by Continuous Flow Chemiluminescence

Cited by 7 publications

References 1 publication

Surface Bridge Hydroxyl-Mediated Promotion of Reactive Oxygen Species in Different Particle Size TiO2 Suspensions

Surface Bridge Hydroxyl-Mediated Promotion of Reactive Oxygen Species in Different Particle Size TiO2 Suspensions

Dynamic Tracking of Highly Toxic Intermediates in Photocatalytic Degradation of Pentachlorophenol by Continuous Flow Chemiluminescence

Metal‐free Semiconductor Photocatalysis for sp2 C−H Functionalization with Molecular Oxygen

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Online Quantification of O₂^·-and H₂O₂and Their Formation Kinetics in Ultraviolet (UV)-Irradiated Nano-TiO₂Suspensions by Continuous Flow Chemiluminescence

Surface Bridge Hydroxyl-Mediated Promotion of Reactive Oxygen Species in Different Particle Size TiO₂ Suspensions

Surface Bridge Hydroxyl-Mediated Promotion of Reactive Oxygen Species in Different Particle Size TiO₂ Suspensions

Metal‐free Semiconductor Photocatalysis for sp² C−H Functionalization with Molecular Oxygen