Ultrahigh oxygen-doped carbon quantum dots for highly efficient H2O2 production via two-electron electrochemical oxygen reduction

Guo, Ying; Zhang, Rong; Zhang, Shaoce; Hu, Hong; Zhao, Yuwei; Huang, Zhaodong; Han, Cuiping; Li, Hongfei; Chen, Zhi

doi:10.1039/d2ee01797k

Cited by 101 publications

(54 citation statements)

References 53 publications

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“…Such O-containing groups play a critical role in the 2e – ORR pathways, which has been verified by theoretical calculations and experiments in many reports. Zhi and co-workers confirmed that the C–O bonds from the ether groups in the carbon quantum dot (CQD) catalyst fabricated by the direct dehydration and carbonization of glucose are the most active sites for the 2e – ORR . The CQD catalyst shows an ultrahigh O content (30.4 atom %) and exhibits an excellent catalytic H 2 O 2 production performance with nearly 100% selectivity.…”

Section: Resultsmentioning

confidence: 97%

“…Zhi and co-workers confirmed that the C−O bonds from the ether groups in the carbon quantum dot (CQD) catalyst fabricated by the direct dehydration and carbonization of glucose are the most active sites for the 2e − ORR. 64 The CQD catalyst shows an ultrahigh O content (30.4 atom %) and exhibits an excellent catalytic H 2 O 2 production performance with nearly 100% selectivity. Wang and co-workers demonstrated by the DFT calculations that the electrons are transferred from carboxyl groups to adjacent carbon, which enhances the adsorption strength toward *OOH intermediates and thus promotes the H 2 O 2 generation with high activity and high selectivity.…”

Section: Resultsmentioning

confidence: 99%

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Selective H₂O₂ Electrosynthesis over Defective Carbon from Electrochemical Etching of Molybdenum Carbide

Zhang

Wang

et al. 2022

ACS Appl. Mater. Interfaces

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The controllable synthesis of specific defective carbon catalysts is crucial for two-electron oxygen reduction reaction (2e − ORR) to generate H 2 O 2 due to the great potential applications. Herein, the defective carbon catalysts (Mo-CDC-ns) were prepared by an electrochemical activation (ECA) method with Mo 2 C/C as a parent. Electrochemical cyclic voltammetry curves, X-ray photoelectron spectroscopy, inductively coupled plasma-mass spectrometry, scanning electron microscopy, and high-resolution transmission electron microscopy confirm the evolution process of a defective carbon structure from the Mo 2 C phase in which Mo species are first oxidized to Mo 6+ species and then the latter are dissolved into the solution and defective carbon is simultaneously formed. Raman and electron paramagnetic resonance spectra reveal that the defect types in Mo-CDC-ns are the edge defect and vacancy defect sites. Compared with the parent Mo 2 C/C, Mo-CDC-ns exhibit gradually increased kinetic current density and selectivity for H 2 O 2 generation with an extension of activation cycles from 10 (Mo-CDC-10) to 30 (Mo-CDC-30). Over Mo-CDC-30, a kinetic current density of 19.4 mA cm −2 and a selectivity close to 90% in 0.1 M KOH solution were achieved, as well as good stability for H 2 O 2 production in an extended test up to 12 h in an H-cell. Graphene planes and Stone Wales 5757-carbon were constructed as basic models for density functional theory calculations. It revealed that the obtained defective structure after the removal of Mo atoms contains the double vacancy at the edge of graphene (Edge-DVC) and the topological defect on the plane of 5757-carbon (5757C-D), which show more moderate reaction free energy for forming *OOH and smaller energy barrier of 2e − ORR.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Selective H₂O₂ Electrosynthesis over Defective Carbon from Electrochemical Etching of Molybdenum Carbide

Zhang

Wang

et al. 2022

ACS Appl. Mater. Interfaces

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“…Further downsizing carbon materials into “quantum dots” can open up the bandgap by creating a quantum confinement effect. [ 46 ] Once the bandgap of carbon is opened (indicated as modified carbon in Figure 4e), the modified carbon can take on the role of the semiconductor, and a space charge region may appear in the modified carbon when it is in contact with a metal or semiconductor. Consequently, an internal electric field can be formed in the metal‐modified carbon Schottky junction or semiconductor‐modified carbon heterojunction.…”

Section: Classification Of the Internal Electric Fieldmentioning

confidence: 99%

Enabling Internal Electric Fields to Enhance Energy and Environmental Catalysis

Chen

Ren

Yuan

2023

Advanced Energy Materials

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Recent years have witnessed an upsurge of interest in exploiting advanced photo‐/electrocatalysts for efficient energy conversion and environmental remediation. Constructing internal electric fields has been highlighted as a rising star to help facilitate various catalytic processes, with the merits of promoting charge transfer/separation, optimizing redox potential and creating effective active/adsorption sites. Internal electric fields are usually formed by the polarization of uneven charge distributions between different constituent layers, which widely exist in piezoelectrics, polar surface terminations, and heterostructure materials. Herein, a groundbreaking and interdisciplinary overview of the latest advances in the construction of internal electric fields to improve photo(electro)catalytic and electrocatalytic activity is provided. This critical review begins with an encyclopedic summary of the classification, advantages, and synthesis strategies of internal electric fields. Subsequently, the identification methods are thoroughly discussed based on the characterization techniques, experiments, and theoretical calculations, which can provide profound guidance for the in‐depth study of internal electric fields. To elaborate the theory–structure–activity relationships for internal electric fields, the corresponding reaction mechanisms, modification strategies, and catalytic performance are jointly discussed, along with a discussion of their practical energy and environmental applications. Finally, an insightful analysis of the challenges and future prospects for internal electric field‐based catalysts are discussed.

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“…Table S3 (Supporting Information) lists the contents of different oxygen groups. Oxygen doping in carbon has been known promoting the two-electron ORR to H 2 O 2 , [29][30][31] while PN and GN species have been known promoting the four-electron ORR. [13,31,32] The electron transfer number (n) follows the order COF 800 > COF 900 > COF 700 in both alkaline and acidic electrolyte.…”

Section: Origin Of the Electrocatalytic Performance Enhancementmentioning

confidence: 99%

Bifunctional Edge‐Rich Nitrogen Doped Porous Carbon for Activating Oxygen and Sulfur

Liu

Zhu

Song

et al. 2023

Adv Funct Materials

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Oxygen reduction reaction (ORR) and sulfur reduction reaction (SRR) play key roles in advanced batteries. However, they both suffer from sluggish reaction kinetics. Here, an interesting nitrogen doped porous carbon material that can simultaneously activate oxygen and sulfur is reported. The carbon precursor is a nitrogen containing covalent organic framework (COF), constituting periodically stacked 2D sheets. The COF structure is well preserved upon pyrolysis, resulting in the formation of edge-rich porous carbon with structure resembling stacked holey graphene. The nitrogen containing groups in the COF are decomposed into graphitic and pyridinic nitrogen during pyrolysis. These edge sites and uniform nitrogen doping endow the carbon product with high intrinsic catalytic activities toward ORR and SRR. The COF derived carbon delivers outstanding performances when assembling as cathodes in the Li-S and Li-O 2 batteries. Simultaneous activation of oxygen and sulfur also enables a new battery chemistry. A proof-of-concept Li-S/O 2 hybrid battery is assembled, delivering a large specific capacity of 2,013 mAh g −1 . This study may inspire novel battery designs based on oxygen and sulfur chemistry.

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Ultrahigh oxygen-doped carbon quantum dots for highly efficient H₂O₂ production via two-electron electrochemical oxygen reduction

Abstract: Direct electrochemical two-electron oxygen reduction (2eORR) into H2O2 provides a promising alternative for on-site green H2O2 production to the predominant anthraquinone oxidation technology. Oxidized carbon materials have demonstrated their impressive...

Cited by 101 publications

References 53 publications

Selective H₂O₂ Electrosynthesis over Defective Carbon from Electrochemical Etching of Molybdenum Carbide

Selective H₂O₂ Electrosynthesis over Defective Carbon from Electrochemical Etching of Molybdenum Carbide

Enabling Internal Electric Fields to Enhance Energy and Environmental Catalysis

Bifunctional Edge‐Rich Nitrogen Doped Porous Carbon for Activating Oxygen and Sulfur

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Ultrahigh oxygen-doped carbon quantum dots for highly efficient H2O2 production via two-electron electrochemical oxygen reduction

Abstract: Direct electrochemical two-electron oxygen reduction (2eORR) into H2O2 provides a promising alternative for on-site green H2O2 production to the predominant anthraquinone oxidation technology. Oxidized carbon materials have demonstrated their impressive...

Cited by 101 publications

References 53 publications

Selective H2O2 Electrosynthesis over Defective Carbon from Electrochemical Etching of Molybdenum Carbide

Selective H2O2 Electrosynthesis over Defective Carbon from Electrochemical Etching of Molybdenum Carbide

Enabling Internal Electric Fields to Enhance Energy and Environmental Catalysis

Bifunctional Edge‐Rich Nitrogen Doped Porous Carbon for Activating Oxygen and Sulfur

Contact Info

Product

Resources

About

Ultrahigh oxygen-doped carbon quantum dots for highly efficient H₂O₂ production via two-electron electrochemical oxygen reduction

Selective H₂O₂ Electrosynthesis over Defective Carbon from Electrochemical Etching of Molybdenum Carbide

Selective H₂O₂ Electrosynthesis over Defective Carbon from Electrochemical Etching of Molybdenum Carbide