Photo‐Driven Quasi‐Topological Transformation Exposing Highly Active Nitrogen Cation Sites for Enhanced Photocatalytic H₂O₂ Production

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(50)

Published: Nov. 7, 2023

Herein, the exposure of highly-active nitrogen cation sites has been accomplished by photo-driven quasi-topological transformation a 1,10-phenanthroline-5,6-dione-based covalent organic framework (COF), which contributes to hydrogen peroxide (H2 O2 ) synthesis during 2-electron photoreduction. The exposed with photo-enhanced Lewis acidity not only act as electron-transfer motor adjust inherent charge distribution, powering continuous and stable separation, broadening visible-light adsorption, but also providing large number active for adsorption. optimal catalyst shows high H2 production rate 11965 μmol g-1 h-1 under visible light irradiation remarkable apparent quantum yield 12.9 % at 400 nm, better than most previously reported COF photocatalysts. This work provides new insights designing photo-switchable catalytic centers toward efficient solar chemical energy conversion.

Language: Английский

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Reduction of Superoxide Radical Intermediate by Polydopamine for Efficient Hydrogen Peroxide Photosynthesis

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(14)

Published: Feb. 10, 2024

Abstract The synthesis of hydrogen peroxide through artificial photosynthesis is a green and promising technology with advantages in sustainability, economy safety. However, superoxide radical (⋅O 2 − ), an important intermediate photocatalytic oxygen reduction to H O production, has strong oxidizing properties that potentially destabilize the catalyst. Therefore, avoiding accumulation ⋅O for its rapid conversion paramount significance improving catalyst stability yield. In this work, strategy was developed utilize protonated groups depletion converted , thereby efficiency from CN successfully enhanced by 47‐fold. experimental findings demonstrated polydopamine not only improved carrier separation efficiency, more importantly, provided adsorption active site efficient production. This work offers versatile approach synthesizing stable photocatalysts.

Language: Английский

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Keto-anthraquinone covalent organic framework for H2O2 photosynthesis with oxygen and alkaline water

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

Published: March 26, 2024

Hydrogen peroxide photosynthesis suffers from insufficient catalytic activity due to the high energy barrier of hydrogen extraction H2O. Herein, we report that mechanochemically synthesized keto-form anthraquinone covalent organic framework which is able directly synthesize H2O2 (4784 μmol h-1 g-1 at λ > 400 nm) oxygen and alkaline water (pH = 13) in absence any sacrificial reagents. The strong alkalinity resulted formation OH-(H2O)n clusters water, were adsorbed on keto moieties within then dissociated into O2 active hydrogen, because was largely lowered. produced reacted with generate anthrahydroquinone, subsequently oxidized by produce H2O2. This study ultimately sheds light importance H2O for demonstrates synthesis achievable under conditions.

Language: Английский

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Nitrogen‐Rich Carbon Dot‐Mediated n→π* Electronic Transition in Carbon Nitride for Superior Photocatalytic Hydrogen Peroxide Production

Advanced Functional Materials, Journal Year: 2024, Volume and Issue: 34(38)

Published: May 7, 2024

Abstract Solar‐driven synthesis of hydrogen peroxide (H 2 O ) through photocatalysis stands out as a promising avenue for sustainable energy generation, marked by environmental friendliness and industrial feasibility. However, the inherent limitations carbon nitride (CN) in photocatalytic H production significantly impede their performance. Herein, novel 0D/2D dots‐modified CN nanosheet heterojunction (CDsMCN) is introduced, synthesized hydrothermal‐calcination tandem strategy induced CDs derived from melamine. This innovative technique enhances n→π* electronic transition CDsMCN, accelerating separation efficiency electron‐hole pairs, boosting oxygen adsorption, promoting highly selective 2e − ORR. Comparative to pristine CN, 10 MCN exhibited remarkable tenfold increase production, reaching an impressive 1.48 mmol L −1 . Furthermore, demonstrates exceptional stability, maintaining its catalytic at initial level over four consecutive cycles. The notable achievement molar selectivity ≈80% onset potential 0.6 V (vs RHE) underscores ability produce desired product selectively. Advanced situ characterization together with DFT calculations revealed that ultrathin enhanced improves optical properties, reduces bandgap, facilitates fast charge migration, increases performance, thereby serving candidate advanced applications.

Language: Английский

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Circumventing bottlenecks in H2O2 photosynthesis over carbon nitride with iodine redox chemistry and electric field effects

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

Published: June 3, 2024

Abstract Artificial photosynthesis using carbon nitride (g-C 3 N 4 ) holds a great promise for sustainable and cost-effective H 2 O production, but the high carrier recombination rate impedes its efficiency. To tackle this challenge, we propose an innovative method involving multispecies iodine mediators (I − /I intercalation through pre-photo-oxidation process potassium iodide (suspected deteriorated “KI”) within g-C framework. Moreover, introduce external electric field by incorporating cationic methyl viologen ions to establish auxiliary electron transfer channel. Such unique design drastically improves separation of photo-generated carriers, achieving impressive production 46.40 mmol g −1 h under visible light irradiation, surpassing most visible-light -producing systems. Combining various advanced characterization techniques elucidates inner photocatalytic mechanism, application potential system is validated with simulation scenarios. This work presents significative strategy preparing applying highly efficient -based catalysts in photochemical production.

Language: Английский

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Large‐Scale Continuous and In Situ Photosynthesis of Hydrogen Peroxide by Sulfur‐Functionalized Polymer Catalyst for Water Treatment

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(10)

Published: Jan. 24, 2024

Photocatalytic H

Language: Английский

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Tris(triazolo)triazine‐Based Covalent Organic Frameworks for Efficiently Photocatalytic Hydrogen Peroxide Production

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(45)

Published: July 1, 2024

Abstract Two‐dimensional covalent organic frameworks (2D‐COFs) have recently emerged as fascinating scaffolds for solar‐to‐chemical energy conversion because of their customizable structures and functionalities. Herein, two tris(triazolo)triazine‐based COF materials (namely COF‐JLU51 COF‐JLU52) featuring large surface area, high crystallinity, excellent stability photoelectric properties were designed constructed the first time. Remarkably, gave an outstanding H 2 O production rate over 4200 μmol g −1 h with reusability in pure water under one standard sun light, that higher than its isomorphic COF‐JLU52 most reported metal‐free materials, owing to superior generation, separation transport photogenerated carriers. Experimental theoretical researches prove photocatalytic process undergoes a combination indirect 2e − reduction reaction (ORR) 4e oxidation (WOR). Specifically, ultrahigh yield 7624.7 apparent quantum 18.2 % was achieved 1 : ratio benzyl alcohol system. This finding contributes novel, nitrogen‐rich high‐quality also designate bright future solar transformations.

Language: Английский

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Introduction of electron-deficient unit in resorcinol-formaldehyde resin to construct donor–acceptor conjugated polymer for enhancing photocatalytic H₂O₂ production

Journal of Materials Chemistry A, Journal Year: 2024, Volume and Issue: 12(14), P. 8420 - 8428

Published: Jan. 1, 2024

Intramolecular donor–acceptor conjugated polymer was constructed in resorcinol-formaldehyde resin by embedding benzothiadiazole, which can reduce the Gibbs free energy for two-electron oxygen reduction and improve photocatalytic H 2 O evolution.

Language: Английский

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Synergistic Utilization of Photogenerated Electrons and Holes in Carbon Nitride Nanosheet Assembly for Enhanced Photocatalytic H2O2 Production

Applied Catalysis B Environment and Energy, Journal Year: 2025, Volume and Issue: unknown, P. 124998 - 124998

Published: Jan. 1, 2025

Language: Английский

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Integrating Multipolar Structures and Carboxyl Groups in sp2‐Carbon Conjugated Covalent Organic Frameworks for Overall Photocatalytic Hydrogen Peroxide Production

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(41)

Published: July 23, 2024

Abstract The direct production of hydrogen peroxide (H 2 O ) through photocatalytic reaction via H and is considered as an ideal approach. However, the efficiency generation generally limited by insufficient charge mass transfer. Covalent organic framework (COFs) offer a promising platform metal‐free photocatalyst for due to their potential rational design at molecular level. Herein, we integrated multipolar structures carboxyl groups into COFs enhance in pure water without any sacrificial agents. introduction octupolar quadrupolar structures, along with increase planarity, created efficient oxygen reduction (ORR) sites. Meanwhile, could not only boost movement enhancement pore hydrophilicity, but also promote proton conduction, enabling conversion from ⋅O − , which crucial intermediate product photocatalysis. Overall, demonstrate that TACOF‐1‐COOH, consisting optimal enrichment sites (carboxyl groups), exhibited yield rate 3542 μmol h 1 g −1 solar‐to‐chemical (SCC) 0.55 %. This work provides valuable insights designing photocatalysts production.

Language: Английский

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