Bifunctional CdS/COF S-scheme photocatalyst for enhanced H2 evolution and organic synthesis

Chemical Engineering Journal, Journal Year: 2023, Volume and Issue: 476, P. 146818 - 146818

Published: Oct. 20, 2023

It is an efficient strategy to construct photocatalysts by integrating the advantages of inorganic semiconductors and covalent organic frameworks (COFs) for H2 generation along with simultaneous oxidation. Herein, inorganic/organic CdS/COF (denoted as TpBD) 2D heterostructure fabricated electrostatic self-assembly method. The ultrathin structure can reduce charge transfer distance, enhance light absorption, multiply reaction sites while S-scheme heterojunction improves separation efficiency. composite acquires outstanding photocatalytic activity 15.1 mmol/g/h, simultaneously convert cheap ascorbic acid value-added 2,3-diketo-L-gulonic acid. Hall effect test elucidates dynamics carrier migration. electron paramagnetic resonance analysis, photo-irradiated Kelvin probe force microscopy, femtosecond transient absorption spectroscopy, theoretical calculation, in-situ irradiation X-ray photoelectron spectroscopy measurements confirm superiority transfer. This research presents new inspiration develop hydrogen production green chemical production.

Language: Английский

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Structural regulation of covalent organic frameworks for advanced electrocatalysis

Nano Energy, Journal Year: 2023, Volume and Issue: 120, P. 109155 - 109155

Published: Dec. 2, 2023

Language: Английский

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Regulated High‐Spin State and Constrained Charge Behavior of Active Cobalt Sites in Covalent Organic Frameworks for Promoting Electrocatalytic Oxygen Reduction

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(27)

Published: May 3, 2023

A novel type of covalent organic frameworks has been developed by assembling definite cobalt-nitrogen-carbon configurations onto carbon nanotubes using linkers that have varying electronic effects. This innovative approach resulted in an efficient electrocatalyst for oxygen reduction, which is understood a combination situ spectroelectrochemistry and the bond order theorem. The strong interaction between electron-donating electron-accepting linker mitigates trend charge loss at cobalt sites, while inducing generation high spin state. enhances adsorption strength electron transfer center reactants/intermediates, leading to improved reduction capability. work not only presents effective strategy developing non-noble metal electrocatalysts through reticular chemistry, but also provides valuable insights into regulating configuration behavior active sites designing high-performance electrocatalysts.

Language: Английский

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Catalytic Linkage Engineering of Covalent Organic Frameworks for the Oxygen Reduction Reaction

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(30)

Published: April 28, 2023

Metal-free covalent organic frameworks (COFs) have been employed to catalyze the oxygen reduction reaction (ORR). To achieve high activity and selectivity, various building blocks containing heteroatoms groups linked by imine bonds were used create catalytic COFs. However, roles of linkages COFs in ORR not investigated. In this work, linkage engineering has modulate behaviors. single sites while avoiding other possible sites, we synthesized from benzene units bonds, such as imine, amide, azine, oxazole bonds. Among these COFs, oxazole-linkage enables with highest activity, which achieved a half-wave potential 0.75 V limited current density 5.5 mA cm-2 . Moreover, oxazole-linked COF conversion frequency (TOF) value 0.0133 S-1 , 1.9, 1.3, 7.4-times that azine-, amide- imine-COFs, respectively. The theoretical calculation showed carbon atoms facilitated formation OOH* promoted protonation O* form OH*, thus advancing activity. This work guides us on are suitable for ORR.

Language: Английский

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A Fluorinated Covalent Organic Framework with Accelerated Oxygen Transfer Nanochannels for High‐Performance Zinc–Air Batteries

Advanced Materials, Journal Year: 2023, Volume and Issue: 35(17)

Published: Feb. 6, 2023

The establishment of abundant three-phase interfaces with accelerated mass transfer in air cathodes is highly desirable for the development high-rate and long-cycling rechargeable zinc-air batteries (ZABs). Covalent organic frameworks (COFs) exhibit tailored nanopore structures, facilitating rational tuning their specific properties. Here, by finely fluorinated nanopores a COF, novel cathode ZABs unprecedentedly designed synthesized. COF nanosheets are decorated alkyl chains, which shows high affinity to oxygen (O2 ), its (fluorinated COF). stacked into well-defined O2 -transport channels, then assembled aerophilic "nano-islands" on hydrophilic FeNi layered-double-hydroxide (FeNi LDH) electrocatalyst surface. Therefore, mass-transport "highway" water segregated nanoscale, significantly enlarges area boundaries greatly promotes mass-transfer therein. based COF-modified deliver small charge/discharge voltage gap (0.64 V at 5 mA cm-2 peak power density (118 mW stable cyclability. This work provides feasible approach design high-performance ZABs, will expand new application COFs.

Language: Английский

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Engineering organic polymers as emerging sustainable materials for powerful electrocatalysts

Chemical Society Reviews, Journal Year: 2024, Volume and Issue: 53(3), P. 1447 - 1494

Published: Jan. 1, 2024

A comprehensive overview on organic polymers as electrocatalysts is summarized. By presenting the engineering strategies, insightful understandings, challenges, and perspectives, we hope this review can provide valuable references for readers.

Language: Английский

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Charging modulation of the pyridine nitrogen of covalent organic frameworks for promoting oxygen reduction reaction

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: Feb. 29, 2024

Abstract Covalent organic frameworks (COFs) are ideal templates for constructing metal-free catalysts the oxygen reduction reaction due to their highly tuneable skeletons and controllable porous channels. However, development of active sites within COFs remains challenging limited electron-transfer capabilities weak binding affinities intermediates. Herein, we constructed catalytic centres by modulating electronic states pyridine nitrogen atoms incorporated into COFs. By incorporating different units (such as pyridine, ionic imidazole units), tuned various properties including dipole moments, reductive ability, hydrophilicity, towards Notably, COF ( im -PY-BPY-COF) exhibited greater activity than neutral (PY-BPY-COF) ion -PY-BPY-COF). Specifically, -PY-BPY-COF demonstrated a half-wave potential 0.80 V in 0.1 M KOH, outperforming other Theoretical calculations situ synchrotron radiation Fourier transform infrared spectroscopy confirmed that carbon rings improved facilitating intermediate OOH* promoting desorption OH*. This study provides new insights design metal-like catalysts.

Language: Английский

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One-dimensional covalent organic frameworks with atmospheric water harvesting for photocatalytic hydrogen evolution from water vapor

Applied Catalysis B Environment and Energy, Journal Year: 2023, Volume and Issue: 338, P. 123074 - 123074

Published: July 7, 2023

Language: Английский

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Developing new-generation covalent organic frameworks as sustainable catalysts: Synthesis, properties, types and solar energy production

Materials Science and Engineering R Reports, Journal Year: 2024, Volume and Issue: 157, P. 100771 - 100771

Published: Jan. 30, 2024

Language: Английский

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Positional Thiophene Isomerization: A Geometric Strategy for Precisely Regulating the Electronic State of Covalent Organic Frameworks to Boost Oxygen Reduction

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(15)

Published: Feb. 13, 2024

Abstract With the oxygen conversion efficiency of metal‐free carbon‐based fuel cells dramatically improved, building blocks covalent organic frameworks (COFs) raised principal concerns on catalytic active sites with indistinct electronic states. Herein, to address this issue, we demonstrate COFs for reduction reaction (ORR) by regulating edge‐hanging thiophene units, and molecular geometries are further modulated via positional isomerization strategy, affording isomeric COF‐α 2‐substitution COF‐β 3‐substitution frameworks. The states intermediate adsorption ability well‐regulated through geometric modification, resulting in controllable chemical activity local density π‐electrons. Notably, introduction units different substitution positions into a pristine pure COF model COF‐Ph achieves excellent half‐wave potential 0.76 V versus reversible hydrogen electrode, which is higher than most those or metal‐based electrocatalysts. Utilizing combination theoretical prediction situ Raman spectra, show that skeleton ( ) can induce dangling unit activation, accurately identifying pentacyclic‐carbon (thiophene α‐position) adjacent sulfur atom as sites. results suggest groups suitable ORR promising geometry construction.

Language: Английский

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