Polarization Engineering of Covalent Triazine Frameworks for Highly Efficient Photosynthesis of Hydrogen Peroxide from Molecular Oxygen and Water

Advanced Materials, Journal Year: 2022, Volume and Issue: 34(28)

Published: May 7, 2022

Two-electron oxygen photoreduction to hydrogen peroxide (H2 O2 ) is seriously inhibited by its sluggish charge kinetics. Herein, a polarization engineering strategy demonstrated grafting (thio)urea functional groups onto covalent triazine frameworks (CTFs), giving rise significantly promoted separation/transport and obviously enhanced proton transfer. The thiourea-functionalized CTF (Bpt-CTF) presents substantial improvement in the photocatalytic H2 production rate 3268.1 µmol h-1 g-1 with no sacrificial agents or cocatalysts that over an order of magnitude higher than unfunctionalized (Dc-CTF), remarkable quantum efficiency 8.6% at 400 nm. Mechanistic studies reveal performance attributed prominently two-electron reduction reaction forming endoperoxide unit highly concentrated holes thiourea site. generated from water oxidation subsequently consumed (ORR), thereby boosting overall findings suggest powerful functional-groups-mediated method for development efficient metal-free polymer-based photocatalysts.

Language: Английский

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Piperazine-Linked Metalphthalocyanine Frameworks for Highly Efficient Visible-Light-Driven H₂O₂ Photosynthesis

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(46), P. 21328 - 21336

Published: Nov. 9, 2022

Artificial photosynthesis of H2O2 from O2 reduction provides an energy-saving, safe, and green approach. However, it is still critical to develop highly active selective 2e– oxygen reaction photocatalysts for efficient production owing the unsatisfactory productivity. Herein, two new two-dimensional piperazine-linked CoPc-based covalent organic frameworks (COFs), namely, CoPc-BTM-COF CoPc-DAB-COF, were afforded nucleophilic substitution hexadecafluorophthalocyaninato cobalt(II) (CoPcF16) with 1,2,4,5-benzenetetramine (BTM) or 3,3′-diaminobenzidine (DAB). Powder X-ray diffraction analysis in combination electron microscopy a series spectroscopic technologies reveals their crystalline porous framework fully conjugated structure eclipsed π-stacking model. Ultraviolet–visible diffuse reflectance absorption spectra unveil excellent light capacity wide range 400–1000 nm. This, together enhanced photo-induced charge separation transport efficiency as disclosed by photocurrent response photoluminescence measurements, endows as-prepared COFs superior photocatalytic activity toward O2-to-H2O2 conversion under visible-light irradiation (λ > 400 nm). In particular, exhibits record-high yield 2096 μmol h–1 g–1 among COF-based impressive apparent quantum 7.2% at 630 The present result should be helpful fabricating high-performance low-cost visible-light-driven photosynthesis.

Language: Английский

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Dual donor-acceptor covalent organic frameworks for hydrogen peroxide photosynthesis

Nature Communications, Journal Year: 2023, Volume and Issue: 14(1)

Published: Aug. 28, 2023

Constructing photocatalytically active and stable covalent organic frameworks containing both oxidative reductive reaction centers remain a challenge. In this study, benzotrithiophene-based with spatially separated redox are rationally designed for the photocatalytic production of hydrogen peroxide from water oxygen without sacrificial agents. The triazine-containing framework demonstrates high selectivity H2O2 photogeneration, yield rate 2111 μM h-1 (21.11 μmol 1407 g-1 h-1) solar-to-chemical conversion efficiency 0.296%. Codirectional charge transfer large energetic differences between linkages linkers verified in double donor-acceptor structures periodic frameworks. sites mainly concentrated on electron-acceptor fragments near imine bond, which regulate electron distribution adjacent carbon atoms to optimally reduce Gibbs free energy O2* OOH* intermediates during formation H2O2.

Language: Английский

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Developing Ni single-atom sites in carbon nitride for efficient photocatalytic H2O2 production

Nature Communications, Journal Year: 2023, Volume and Issue: 14(1)

Published: Nov. 6, 2023

Photocatalytic two-electron oxygen reduction to produce high-value hydrogen peroxide (H2O2) is gaining popularity as a promising avenue of research. However, structural evolution mechanisms catalytically active sites in the entire photosynthetic H2O2 system remains unclear and seriously hinders development highly-active stable photocatalysts. Herein, we report high-loading Ni single-atom photocatalyst for efficient synthesis pure water, achieving an apparent quantum yield 10.9% at 420 nm solar-to-chemical conversion efficiency 0.82%. Importantly, using situ synchrotron X-ray absorption spectroscopy Raman directly observe that initial Ni-N3 dynamically transform into high-valent O1-Ni-N2 after O2 adsorption further evolve form key *OOH intermediate before finally forming HOO-Ni-N2. Theoretical calculations experiments reveal structure reduces formation energy barrier suppresses O=O bond dissociation, leading improved production activity selectivity.

Language: Английский

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Photocatalytic hydrogen peroxide evolution: What is the most effective strategy?

Nano Energy, Journal Year: 2022, Volume and Issue: 104, P. 107906 - 107906

Published: Oct. 19, 2022

Language: Английский

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Sulfone‐Modified Covalent Organic Frameworks Enabling Efficient Photocatalytic Hydrogen Peroxide Generation via One‐Step Two‐Electron O₂ Reduction

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(26)

Published: April 25, 2023

Abstract Photocatalytic oxygen reduction reaction (ORR) offers a promising hydrogen peroxide (H 2 O ) synthetic strategy, especially the one‐step two‐electron (2e − ORR route holds great potential in achieving highly efficient and selectivity. However, 2e is rarely harvested underlying mechanism for regulating pathways remains greatly obscure. Here, by loading sulfone units into covalent organic frameworks (FS‐COFs), we present an photocatalyst H generation via from pure water air. Under visible light irradiation, FS‐COFs exert superb yield of 3904.2 μmol h −1 g , outperforming most reported metal‐free catalysts under similar conditions. Experimental theoretical investigation reveals that accelerate separation photoinduced electron‐hole (e ‐h + pairs, enhance protonation COFs, promote adsorption Yeager‐type, which jointly alters process two‐step to one, thereby with high

Language: Английский

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Constructing Synergistic Triazine and Acetylene Cores in Fully Conjugated Covalent Organic Frameworks for Cascade Photocatalytic H₂O₂ Production

Chemistry of Materials, Journal Year: 2022, Volume and Issue: 34(11), P. 5232 - 5240

Published: May 16, 2022

Covalent organic frameworks (COFs) are an ideal template for photocatalytic H2O2 synthesis because of the tunable chemical structures and semiconductor properties. However, photoactivity COFs is still under-improved due to inefficient intrinsic charge generation, fast recombination photogenerated charges, limited electron transport along frameworks. Herein, spatially separated synergistic triazine acetylene units first integrated into (EBA-COF BTEA-COF) production. The spatial separation cores leads efficient suppressed recombination, C═C linkage facilitates electrons over skeletons. Both experimental computational results suggested that synergistically promote in a two-electron pathway. EBA-COF showed attractive activity with production rate 1830 μmol h–1 gcat–1, superior most other COF-based catalysts. This study provides method designing photocatalysts active sites based on vinylene-linked COFs.

Language: Английский

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Solar‐to‐H₂O₂ Catalyzed by Covalent Organic Frameworks

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(49)

Published: Aug. 14, 2023

Abstract Benefiting from the excellent structural tunability, robust framework, ultrahigh porosity, and rich active sites, covalent organic frameworks (COFs) are widely recognized as promising photocatalysts in chemical conversions, emerged hydrogen peroxide (H 2 O ) photosynthesis 2020. H , serving an environmental‐friendly oxidant a liquid fuel, has attracted increasing researchers to explore its potential. Over past few years, numerous COFs‐based developed with encouraging achievements production, whereas no comprehensive review articles exist summarize this specific significant area. Herein we provide systematic overview of advances challenges COFs photocatalytic production. We first introduce priorities photosynthesis. Then, various strategies improve efficiency discussed. The perspective outlook for future emerging field finally offered. This timely will pave way development highly efficient practical production value‐added chemicals not limited .

Language: Английский

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Covalent Organic Frameworks Containing Dual O₂Reduction Centers for Overall Photosynthetic Hydrogen Peroxide Production

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 62(9)

Published: Dec. 28, 2022

Covalent organic frameworks (COFs) are highly desirable for achieving high-efficiency overall photosynthesis of hydrogen peroxide (H2 O2 ) via molecular design. However, precise construction COFs toward photosynthetic H2 remains a great challenge. Herein, we report the crystalline s-heptazine-based (HEP-TAPT-COF and HEP-TAPB-COF) with separated redox centers efficient production from pure water. The spatially orderly active sites in HEP-COFs can efficiently promote charge separation enhance photocatalytic production. Compared HEP-TAPB-COF, HEP-TAPT-COF exhibits higher efficiency integrating dual reduction s-heptazine triazine moieties. Accordingly, bearing remarkable solar-to-chemical energy 0.65 % high apparent quantum 15.35 at 420 nm, surpassing previously reported COF-based photocatalysts.

Language: Английский

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Covalent organic frameworks towards photocatalytic applications: Design principles, achievements, and opportunities

Coordination Chemistry Reviews, Journal Year: 2022, Volume and Issue: 475, P. 214882 - 214882

Published: Oct. 14, 2022

Language: Английский

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