Defective, oxygen-functionalized multi-walled carbon nanotubes as an efficient peroxymonosulfate activator for degradation of organic pollutants

Adil, Sawaira; Kim, Woong Sub; Kim, Tae Hyeong; Lee, Seonghyun; Hong, Seok Won; Kim, Eunju

doi:10.1016/j.jhazmat.2020.122757

Cited by 125 publications

(16 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…From quantitative analyses of EPR results, the contents of 1 O 2 were calculated to be up to 99%. In contrast, for Fe NP /ND, • OH and • SO 4 – were obviously generated, which can be attributed to the radical-generating catalytic route for PMS reduction over Fe NP /ND (Fe (low valence) + HSO 5 – → Fe (high valence) + • SO 4 – + OH – ) rather than non-radical-generating catalytic route for PMS oxidation over Fe 1 /ND (Fe (high valence) + HSO 5 – → Fe (low valence) + • SO 4 – + 1/2 1 O 2 + H + ). ,− Moreover, Fe 1 /CN SAC also exhibited near 100% selectivity for 1 O 2 generation, which further confirmed the unique electronic structure of the single-atom metal site preferring to accept electrons from PMS for its oxidation along a non-radical-generating catalytic route. Nevertheless, the quantitative analyses of EPR results displayed that the content of 1 O 2 generated on flat Fe 1 –N 4 single-atom site is much lower than that of curved Fe 1 –N 4 site.…”

Section: Resultsmentioning

confidence: 92%

Unprecedented Relay Catalysis of Curved Fe₁–N₄ Single-Atom Site for Remarkably Efficient ¹O₂ Generation

Yang

Sun

et al. 2022

ACS Catal.

View full text Add to dashboard Cite

The design of catalysts and catalytic processes for high efficiency and selectivity of important singlet oxygen ( 1 O 2 ) active species generation in oxidation reactions is still challenging, especially utilizing abundant and environmental O 2 without photoelectric field or extra thermal condition. Herein, a curved Fe 1 −N 4 single-atom site is developed by incorporating isolated Fe single atom into nanodiamond with high-curvature surface. It leads to an unprecedented relay catalysis route, in which the activation of O 2 is coupled with peroxymonosulfate (PMS) activation, to efficiently generate 1 O 2 species. In detail, PMS is first activated on the curved Fe 1 −N 4 site with electron donation to Fe single atom, accompanied by 1/2 equiv of 1 O 2 production. More importantly, due to the compressive strain of the curved Fe 1 −N 4 site with a higher energy level of Fe 3d z 2 orbital, the curved Fe 1 −N 4 site with electron charge acquisition can directly transfer electron to O 2 molecule and consequently trigger the generation of additional 1 equiv of 1 O 2 . Taking advantage of this tandem process, remarkable efficiency and near 100% selectivity of 1 O 2 generation are achieved, which leads to an ultrahigh metal catalytic efficiency of 0.77 min −1 for tetracycline oxidative degradation and an outstanding catalytic performance for benzene alcohol selective oxidation. This work, on the one hand, opens up an efficient way to generate 1 O 2 by O 2 activation in peroxide-based catalytic oxidations, and on the other hand, develops a bifunctional Fe 1 −N 4 single-atom site with rapid electron gain and loss ability, which sheds light on further improving catalytic performance in single-atom catalysts via relay catalysis mechanism.

show abstract

Section: Resultsmentioning

confidence: 92%

Unprecedented Relay Catalysis of Curved Fe₁–N₄ Single-Atom Site for Remarkably Efficient ¹O₂ Generation

Yang

Sun

et al. 2022

ACS Catal.

View full text Add to dashboard Cite

show abstract

“…In particular, structural defects in graphene disturb the sp 2 -hybridized carbon matrix and result in a redistribution of electrons around the defects. Delocalized electrons at the carbon defects facilitate the PMS adsorption and activation. − According to the result of the quenching experiment, EPR, and LSV curves, O 2 •– plays the most important role, which can be transformed into 1 O 2 quickly for phenol degradation in the N,S-G-CO 2 @PMS systems.…”

Section: Results and Discussionmentioning

confidence: 99%

Fine-Tuning Radical/Nonradical Pathways on Graphene by Porous Engineering and Doping Strategies

et al. 2021

View full text Add to dashboard Cite

Nitrogen and sulfur co-doped graphene (N,S-G) is activated using ZnCl2, KOH, and CO2 to develop different defects and functionalities. The modified carbo-catalysts are used to activate peroxymonosulfate (PMS) for phenol degradation. Compared with nitrogen-doped graphene (N-G), N,S-G exhibits better catalytic activity, and KOH activation further enhances the oxidation efficiency. Radical quenching experiments, electrochemical characterization, and electron paramagnetic resonance characterization reveal that N-G activates PMS via a nonradical pathway. The involvement of a secondary sulfur dopant will transform the reaction pathway into radical-dominated oxidation (SO4 •–and •OH). KOH activation further promotes the generation of the two radical species and further involves superoxide ion radicals (O2 •–), thus achieving deeper mineralization of the organic pollutants. Different from the nonradical species confined on the catalyst surface, radical oxidation (including the singlet oxygen (1O2) transformed from O2 •–) occurs in bulk solution and protects the carbo-catalyst from corrosion, herein securing better structural integrity and stability of carbo-catalysts. Based on the structure–activity features, we designed a high-performance scalable carbo-catalyst of KOH-activated and N,S-codoped graphene (N,S-G-rGO-KOH) using a facile strategy, which is promising for practical applications.

show abstract

“…Several studies tried to tune the type and density of surface functional groups of CNTs in order to improve the catalytic performance [ 25 , 33 ]. Adil et al [ 34 ] fabricated CNTs with surface oxygen functional groups through a repeated oxidation–reduction cycle of cobalt oxide, which displayed 6 times higher degradation rate in PMS activation to degrade 4-chlorophenol than that of primitive CNTs. After treating with concentrated H 2 SO 4 , H 3 PO 4 , KMnO 4 and H 2 O 2 in sequence, the CNTs could effectively activate PMS to degrade acetaminophen, and the pyridinic N and surface carbonyl groups of CNTs were dominate active sites [ 35 ].…”

Section: Introductionmentioning

confidence: 99%

Improvement of Carbonyl Groups and Surface Defects in Carbon Nanotubes to Activate Peroxydisulfate for Tetracycline Degradation

et al. 2023

View full text Add to dashboard Cite

Carbon nanotubes (CNTs) were considered a promising activator for persulfates due to their high electrical conductivity, large specific surface area and low toxicity. The functional groups and surface defects of CNTs could significantly affect their activation performance. In this study, CNTs with high C=O ratio and defect density (CNT-O-H) were prepared through a facile treatment of raw CNTs with HNO3 oxidation followed by calcination at 800 °C under an argon atmosphere. X-ray photoelectron spectroscopy (XPS) and Raman results showed that the C=O proportion and defect degree (ID/IG) rose to 75% and 1.53, respectively. The obtained CNT-O-H possessed a superior performance towards peroxydisulfate (PDS) activation, and the degradation efficiency of tetracycline (TC) in the CNT-O-H/PDS system was increased to 75.2% from 56.2% of the raw CNTs/PDS system within 40 min. Moreover, the activity of CNT-O-H after use could be easily recovered with re-calcination. In addition, the CNT-O-H/PDS system exhibited high adaptabilities towards wide solution pH (2–10), common coexisting substances and diverse organic pollutants. Singlet oxygen (1O2) was confirmed to be the dominant reactive oxygen species (ROS) generated in the CNT-O-H/PDS system. It was inferred that surface C=O groups and defects of CNTs were the key site to activate PDS for TC degradation.

show abstract

Defective, oxygen-functionalized multi-walled carbon nanotubes as an efficient peroxymonosulfate activator for degradation of organic pollutants

Cited by 125 publications

References 56 publications

Unprecedented Relay Catalysis of Curved Fe₁–N₄ Single-Atom Site for Remarkably Efficient ¹O₂ Generation

Unprecedented Relay Catalysis of Curved Fe₁–N₄ Single-Atom Site for Remarkably Efficient ¹O₂ Generation

Fine-Tuning Radical/Nonradical Pathways on Graphene by Porous Engineering and Doping Strategies

Improvement of Carbonyl Groups and Surface Defects in Carbon Nanotubes to Activate Peroxydisulfate for Tetracycline Degradation

Contact Info

Product

Resources

About

Defective, oxygen-functionalized multi-walled carbon nanotubes as an efficient peroxymonosulfate activator for degradation of organic pollutants

Cited by 125 publications

References 56 publications

Unprecedented Relay Catalysis of Curved Fe1–N4 Single-Atom Site for Remarkably Efficient 1O2 Generation

Unprecedented Relay Catalysis of Curved Fe1–N4 Single-Atom Site for Remarkably Efficient 1O2 Generation

Fine-Tuning Radical/Nonradical Pathways on Graphene by Porous Engineering and Doping Strategies

Improvement of Carbonyl Groups and Surface Defects in Carbon Nanotubes to Activate Peroxydisulfate for Tetracycline Degradation

Contact Info

Product

Resources

About

Unprecedented Relay Catalysis of Curved Fe₁–N₄ Single-Atom Site for Remarkably Efficient ¹O₂ Generation

Unprecedented Relay Catalysis of Curved Fe₁–N₄ Single-Atom Site for Remarkably Efficient ¹O₂ Generation