Assessing the Use of Probes and Quenchers for Understanding the Reactive Species in Advanced Oxidation Processes

Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(13), P. 5433 - 5444

Published: March 17, 2023

Advanced oxidation processes (AOPs) are increasingly applied in water and wastewater treatment. Understanding the role of reactive species using probes quenchers is one main requirements for good process design. However, much fundamental kinetic data reactions with lacking, probably leading to inappropriate probe quencher selection dosing. In this work, second-order rate constants over 150 such as •OH, SO4•-, Cl• chemical oxidants free chlorine persulfate were determined. Some previously ill-quantified (e.g., furfuryl alcohol methyl phenyl sulfoxide certain oxidants, nitrobenzene 1,4-dioxane halogen radicals) found be kinetically favorable. The specific can guided by improved database. criteria properly choosing dosages proposed along a procedure quantifying interference from addition. limitations approaches explicated, possible solutions combination other tools) proposed. Overall, database protocols provided work benefit future research understanding radical chemistry AOPs well radical-involved processes.

Language: Английский

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Generating High‐valent Iron‐oxo ≡Fe^IV=O Complexes in Neutral Microenvironments through Peroxymonosulfate Activation by Zn−Fe Layered Double Hydroxides

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(42)

Published: Aug. 1, 2022

The universal limit on the pH conditions is disturbing peroxymonosulfate (PMS)-triggered high-valent iron-oxo systems in environmental applications. Here, we propose for first time construction of a neutral microenvironment surface Zn-Fe layered double hydroxide (ZnFe-LDH) by using amphoteric properties zinc hydroxide, which continuously generates ≡FeIV =O over wide range 3.0-11.0 activating PMS. ≡Zn(OH)2 moiety offers at phase interface, mitigates self-decomposition protons and hydrolysis reaction iron hydroxyl groups, supported Mossbauer spectra, density functional theory calculations designed experiments. Consequently, ZnFe-LDH/PMS can satisfy stability long-term experiments, selectivity under with high salinity or natural organic matter efficient treatment actual wastewater.

Language: Английский

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Selective Photoelectrocatalytic Glycerol Oxidation to Dihydroxyacetone via Enhanced Middle Hydroxyl Adsorption over a Bi₂O₃-Incorporated Catalyst

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(17), P. 7720 - 7730

Published: March 30, 2022

Photoelectrocatalytic (PEC) glycerol oxidation offers a sustainable approach to produce dihydroxyacetone (DHA) as valuable chemical, which can find use in cosmetic, pharmaceutical industries, etc. However, it still suffers from the low selectivity (≤60%) that substantially limits application. Here, we report PEC of DHA with 75.4% over heterogeneous photoanode Bi2O3 nanoparticles on TiO2 nanorod arrays (Bi2O3/TiO2). The be maintained at ∼65% under relatively high conversion (∼50%). existing p-n junction between and promotes charge transfer thus guarantees photocurrent density. Experimental combined theoretical studies reveal prefers interact middle hydroxyl facilitates selective DHA. Comprehensive reaction mechanism suggest follows two parallel pathways, including electrophilic OH* (major) lattice oxygen (minor) oxidations. Finally, designed self-powered system, achieving productivity 1.04 mg cm-2 h-1 >70% H2 0.32 mL h-1. This work may shed light potential strategy for biomass valorization toward value-added products via anode surface engineering.

Language: Английский

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Elucidating the Mechanistic Origin of a Spin State-Dependent FeN_x–C Catalyst toward Organic Contaminant Oxidation via Peroxymonosulfate Activation

Environmental Science & Technology, Journal Year: 2021, Volume and Issue: 56(2), P. 1321 - 1330

Published: Dec. 23, 2021

Atomically dispersed metals on nitrogen-doped carbon matrices have attracted extensive interest in the removal of refractory organic pollutants. However, a thorough exploration particular structure for each active site and specific effects these sites still remains elusive. Herein, an Fe-pyridinic N4 single-atom catalyst (FeNx-C) was constructed using facile pyrolysis strategy, it exhibited superior catalytic activity peroxymonosulfate (PMS) activation toward contaminant oxidation. The various Fe species relative amounts FeNx-C were validated X-ray absorption spectroscopy 57Fe Mössbauer spectroscopy, which showed critical dependencies precursor ratio calcination temperature. positive correlations between content high-spin state (FeII FeIII) performance found to determine reactive generation electron transfer pathway FeNx-C/PMS system. Moreover, theoretical calculation results revealed that FeII-N4 (S = 2) tends activate PMS form sulfate hydroxyl radicals via one-electron process, while FeIII-N4 moiety 5/2) is prone high-valent iron with lower free energy. Benefiting from finely tuned sites, achieved favorable applicability actual wastewater treatment efficient resistance common water matrix. present work advances mechanistic understanding spin state-dependent persulfate catalysts provides guidance design based descriptions.

Language: Английский

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Switching of radical and nonradical pathways through the surface defects of Fe3O4/MoO S in a Fenton-like reaction

Science Bulletin, Journal Year: 2023, Volume and Issue: 68(6), P. 603 - 612

Published: Feb. 25, 2023

Language: Английский

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Deciphering the Space Charge Effect of the p–n Junction between Copper Sulfides and Molybdenum Selenides for Efficient Water Electrolysis in a Wide pH Range

ACS Nano, Journal Year: 2022, Volume and Issue: 16(9), P. 15425 - 15439

Published: Aug. 29, 2022

Space charge transfer is crucial for an efficient electrocatalytic process, especially narrow-band-gap metal sulfides/selenides. Herein, we designed and synthesized a core-shell structure which ultrathin MoSe2 nanosheet coated CuS hollow nanoboxes (CuS@MoSe2) to form open p-n junction structure. The space effect in the region will greatly improve electron mass conduction, also have abundant active interfaces. It was used as bifunctional electrocatalyst water oxidation at wide pH range. exhibits low overpotential of 49 mV HER 236 OER current density 10 mA·cm-2 acidic pH, 72 219 alkaline 62 230 under neutral conditions. experimental results functional theory calculations testify that CuS@MoSe2 has strong with synergistic effect. built-in field can boost transport during process stabilize charged center junction. This be beneficial performance. work provides understanding semiconductor heterojunction applications regulating electronic sites.

Language: Английский

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Generation of Fe^IV=O and its Contribution to Fenton‐Like Reactions on a Single‐Atom Iron−N−C Catalyst

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(10)

Published: Jan. 10, 2023

Generating FeIV =O on single-atom catalysts by Fenton-like reaction has been established for water treatment; however, the generation pathway and oxidation behavior remain obscure. Employing an Fe-N-C catalyst with a typical Fe-N4 moiety to activate peroxymonosulfate (PMS), we demonstrate that generating is mediated Fe-N-C-PMS* complex-a well-recognized nonradical species induction of electron-transfer oxidation-and determined adjacent Fe sites specific Fe1 -Fe1 distance are required. After atoms <4 Å PMS-saturated, formed 4-5 can coordinate FeII -N4 , forming inter-complex enhanced charge transfer produce =O. enables system efficiently oxidize various pollutants in substrate-specific, pH-tolerant, sustainable manner, where its prominent contribution manifests higher one-electron potential.

Language: Английский

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Interlayer Structure Manipulation of Iron Oxychloride by Potassium Cation Intercalation to Steer H₂O₂ Activation Pathway

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(10), P. 4294 - 4299

Published: Feb. 4, 2022

Structural regulation of the active centers is often pivotal in controlling catalytic functions, especially iron-based oxidation systems. Here, we discovered a significantly altered pathway via simple cation intercalation into layered iron oxychloride (FeOCl) scaffold. Upon FeOCl with potassium iodide (KI), new stable phase K+-intercalated (K-FeOCl) was formed slided layers, distorted coordination, and high-spin Fe(II) species compared to pristine precursor. This structural manipulation steers H2O2 activation from traditional Fenton-like on nonradical ferryl (Fe(IV)═O) pathway. Consequently, K-FeOCl catalyst can efficiently remove various organic pollutants almost 2 orders magnitude faster reaction kinetics than other Fe-based materials an oxidative coupling or polymerization A reaction-filtration coupled process based finally demonstrated could potentially reduce energy consumption by 50%, holding great promise sustainable pollutant removal technologies.

Language: Английский

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Electronegative Cl− modified BiVO4 photoanode synergized with nickel hydroxide cocatalyst for high-performance photoelectrochemical water splitting

Chemical Engineering Journal, Journal Year: 2022, Volume and Issue: 454, P. 140081 - 140081

Published: Oct. 30, 2022

Language: Английский

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Ru-P pair sites boost charge transport in hematite photoanodes for exceeding 1% efficient solar water splitting

Proceedings of the National Academy of Sciences, Journal Year: 2023, Volume and Issue: 120(27)

Published: June 26, 2023

Fast transport of charge carriers in semiconductor photoelectrodes are a major determinant the solar-to-hydrogen efficiency for photoelectrochemical (PEC) water slitting. While doping metal ions as single atoms/clusters has been popularly used to regulate their transport, PEC performances often low due limited mobility and severe recombination. Here, we disperse Ru P diatomic sites onto hematite (DASs Ru-P:Fe 2 O 3 ) construct an efficient photoelectrode inspired by concept correlated single-atom engineering. The resultant photoanode shows superior photocurrent densities 4.55 6.5 mA cm −2 at 1.23 1.50 V RHE , low-onset potential 0.58 high applied bias photon-to-current conversion 1.00% under one sun illumination, which much better than pristine Fe . A detailed dynamic analysis reveals that remarkable synergetic ineraction reduced recombination concentration with substitution site well construction Ru-P bonds material increases carrier separation fast transportation dynamics. systematic simulation study further proves superiority compared Ru-O bonds, allows more long-lived participate oxidation reaction. This work offers effective strategy enhancing dynamics constructing pair into semiconductors, may be extended other solar splitting.

Language: Английский

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