Mn₂O₃ as an Electron Shuttle between Peroxymonosulfate and Organic Pollutants: The Dominant Role of Surface Reactive Mn(IV) Species

Environmental Science & Technology, Journal Year: 2022, Volume and Issue: 56(7), P. 4498 - 4506

Published: March 17, 2022

The environmentally benign Mn oxides play a crucial role in the transformation of organic contaminants, either through catalytically decomposing oxidants, e.g., peroxymonosulfate (PMS), or directly oxidizing target pollutants. Because their dual roles and complex surface chemical reactions, mechanism involved oxide-catalyzed PMS activation processes remains obscure. Here, we clearly elucidate Mn2O3 catalyzed process by means separating pollutant oxidation process. acts as shuttle that mediates electron transfer from substrates to PMS, accompanied redox cycle Mn(IV)/Mn(III). Multiple experimental results indicate is bound form an inner-sphere complex, which then decomposes long-lived reactive Mn(IV) species, without generation sulfate radicals (SO4•–) hydroxyl (HO•). species are proposed be responsible for degradation contaminants (e.g., phenol) formation singlet oxygen (1O2), followed regeneration Mn(III) sites on Mn2O3. This study advances fundamental understanding underlying transition metal processes.

Language: Английский

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Coordination Number Dependent Catalytic Activity of Single‐Atom Cobalt Catalysts for Fenton‐Like Reaction

Advanced Functional Materials, Journal Year: 2022, Volume and Issue: 32(38)

Published: July 7, 2022

Abstract Single‐atom catalysts (SACs) are widely investigated in Fenton‐like reactions for environmental remediation, wherein their catalytic performance can be further improved by coordination structure modulation, but the relevant report is rare. Herein, a series of atomically dispersed cobalt with diverse numbers (denoted as CoN x , represents nitrogen number) synthesized and peroxymonosulfate (PMS) conversion explored. The specific activity found to dependent on number single atomic Co sites, where lowest‐coordinated 2 catalyst exhibits highest PMS activation, followed under‐coordinated 3 normal 4 . Experimental theoretical results reveal that reducing increase electron density atom which governs catalysts. Specifically, entire Co–pyridinic NC motif serves active centers conversion, atom, pyridinic N‐bonded C atoms along vacancy neighboring unsaturated N moiety account reduction oxidation toward radical singlet oxygen ( 1 O ) generation, respectively. These findings provide useful avenue regulation SACs applications.

Language: Английский

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Oxygen doping of cobalt-single-atom coordination enhances peroxymonosulfate activation and high-valent cobalt–oxo species formation

Proceedings of the National Academy of Sciences, Journal Year: 2023, Volume and Issue: 120(16)

Published: April 11, 2023

The high-valent cobalt-oxo species (Co(IV)=O) is being increasingly investigated for water purification because of its high redox potential, long half-life, and antiinterference properties. However, generation Co(IV)=O inefficient unsustainable. Here, a cobalt-single-atom catalyst with N/O dual coordination was synthesized by O-doping engineering. O-doped (Co-OCN) greatly activated peroxymonosulfate (PMS) achieved pollutant degradation kinetic constant 73.12 min-1 g-2, which 4.9 times higher than that Co-CN (catalyst without O-doping) those most reported single-atom catalytic PMS systems. Co-OCN/PMS realized dominant oxidation pollutants increasing the steady-state concentration (1.03 × 10-10 M) 5.9 compared Co-CN/PMS. A competitive kinetics calculation showed contribution to micropollutant 97.5% during process. Density functional theory calculations influenced charge density (increased Bader transfer from 0.68 0.85 e), optimized electron distribution Co center d-band -1.14 -1.06 eV), enhanced adsorption energy -2.46 -3.03 eV, lowered barrier key reaction intermediate (*O*H2O) formation 1.12 0.98 eV. Co-OCN fabricated on carbon felt flow-through device, continuous efficient removal micropollutants (degradation efficiency >85% after 36 h operation). This study provides new protocol activation elimination through heteroatom-doping metal-oxo purification.

Language: Английский

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The debatable role of singlet oxygen in persulfate-based advanced oxidation processes

Water Research, Journal Year: 2023, Volume and Issue: 235, P. 119925 - 119925

Published: March 28, 2023

Language: Английский

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Facile Synthesis of Atomic Fe‐N‐C Materials and Dual Roles Investigation of Fe‐N₄ Sites in Fenton‐Like Reactions

Advanced Science, Journal Year: 2021, Volume and Issue: 8(22)

Published: Oct. 12, 2021

Fenton-like reactions with persulfates as the oxidants have attracted increasing attentions for remediation of emerging antibiotic pollutions. However, developing effective activators outstanding activities and long-term stabilities remains a great challenge in these reactions. Herein, novel activator is successfully synthesized single iron atoms anchored on porous N-doped carbon (Fe-N-PC) by facile chemical vapor deposition (CVD) method. The Fe are coordinated four N according to XANES, Fe-N4 -PC shows enhanced activity activation peroxymonosulfate (PMS) degrade sulfamethoxazole (SMX). experiments density functional theory (DFT) calculations reveal that introduction will regulate main active sites from graphite into , thus could enhance stability tune PMS pathway non-radical radical dominated process. In addition, connected -C structure can be used adsorption organic molecules materials. Therefore, here has dual roles antibiotics activation. CVD performance based reactions, potential environmental field.

Language: Английский

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Recent advances in the applications of encapsulated transition-metal nanoparticles in advanced oxidation processes for degradation of organic pollutants: A critical review

Applied Catalysis B Environment and Energy, Journal Year: 2023, Volume and Issue: 342, P. 123401 - 123401

Published: Oct. 18, 2023

Language: Английский

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Carbon materials in persulfate-based advanced oxidation processes: The roles and construction of active sites

Journal of Hazardous Materials, Journal Year: 2021, Volume and Issue: 426, P. 128044 - 128044

Published: Dec. 9, 2021

Language: Английский

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Origin of the Excellent Activity and Selectivity of a Single-Atom Copper Catalyst with Unsaturated Cu-N₂ Sites via Peroxydisulfate Activation: Cu(III) as a Dominant Oxidizing Species

Environmental Science & Technology, Journal Year: 2022, Volume and Issue: 56(12), P. 8765 - 8775

Published: May 12, 2022

As an efficient active oxidant for the selective degradation of pollutants in wastewater, high-valent copper species Cu(III) with persulfate activation has attracted substantial attention some Cu-based catalysts. However, systematic study a catalyst structure and mechanism about peroxydisulfate (PDS) is challenging owing to coexistence multiple Cu structural symmetry PDS. Herein, we anchored atom two pyridinic N atoms synthesize single-atom (CuSA-NC). Experimental characterizations theoretical calculations complemented each other well because uniform atomic sites. The was identified as site, unsaturated Cu-N2 configuration more conductive PDS than saturated Cu-N4 configuration. Benefiting from generation Cu(III), CuSA-NC exhibited obvious anti-interference performance pollutant complex matrix. superior catalytic activity compared that reported catalysts good durability continuous-flow experiment further revealed potential practical applications. This work strongly deepens understanding sites under develops approach actual water purification.

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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Outlook on Single Atom Catalysts for Persulfate-Based Advanced Oxidation

ACS ES&T Engineering, Journal Year: 2022, Volume and Issue: 2(10), P. 1776 - 1796

Published: Sept. 7, 2022

Single atom catalysts (SACs) have emerged as a promising catalyst material architecture for energy, chemical, and environmental applications. In the past several years, SACs been increasingly explored persulfate-based advanced oxidation processes (AOPs) due to their superior persulfate activation pollutant degradation performance compared benchmark dissolved ion nanoparticle catalysts. However, there still exist uncertainties on mechanism of by SACs, which involves complex interplay sulfate hydroxyl radicals, singlet oxygen, high-valent metal species, and/or mediated electron transfer. Questions also remain how ions molecularly align single site, are converted into reactive what design parameters lead higher efficiency degradation. this critical review, we examine SAC materials employed AOPs discuss they function differently counterparts. We further our discussion current limitations, opportunities, future research needs in (i) filling knowledge gaps mechanisms persulfate-SAC interactions; (ii) augmenting fundamental with theoretical simulation situ characterization techniques; (iii) improving tailored applications; (iv) proactively considering challenges associated engineering practices water matrixes.

Language: Английский

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