Integrating Bifunctionality and Chemical Stability in Covalent Organic Frameworks via One-Pot Multicomponent Reactions for Solar-Driven H₂O₂ Production

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(5), P. 2975 - 2984

Published: Jan. 25, 2023

Multicomponent reactions (MCRs) can be used to introduce different functionalities into highly stable covalent organic frameworks (COFs). In this work, the irreversible three-component Doebner reaction is utilized synthesize four chemically quinoline-4-carboxylic acid DMCR-COFs (DMCR-1-3 and DMCR-1NH) equipped with an acid-base bifunctionality. These show superior photocatalytic H2O2 evolution (one of most important industrial oxidants) compared imine COF analogue (Imine-1). This achieved sacrificial oxidants but also in pure water under oxygen or air atmosphere. Furthermore, high photostability, durability, recyclability. MCR-COFs thus provide a viable materials' platform for solar chemical energy conversion.

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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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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Oxidation‐Reduction Molecular Junction Covalent Organic Frameworks for Full Reaction Photosynthesis of H₂O₂

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

Published: Dec. 30, 2022

The full reaction photosynthesis of H2 O2 that can combine water-oxidation and oxygen-reduction without sacrificial agents is highly demanded to maximize the light-utilization overcome complex reaction-process anthraquinone-oxidation. Here, a kind oxidation-reduction molecular junction covalent-organic-framework (TTF-BT-COF) has been synthesized through covalent-coupling tetrathiafulvalene (photo-oxidation site) benzothiazole (photo-reduction site), which presents visible-light-adsorption region, effective electron-hole separation-efficiency photo-redox sites enables generation . Specifically, record-high yield (TTF-BT-COF, ≈276 000 μM h-1 g-1 ) for achieved among porous crystalline photocatalysts. This first work design COFs , might extend scope in production.

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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Thiophene‐Containing Covalent Organic Frameworks for Overall Photocatalytic H₂O₂ Synthesis in Water and Seawater

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(38)

Published: Aug. 1, 2023

H2 O2 is a significant chemical widely utilized in the environmental and industrial fields, with growing global demand. Without sacrificial agents, simultaneous photocatalyzed synthesis through oxygen reduction reaction (ORR) water oxidation (WOR) dual channels from seawater green sustainable but still challenging. Herein, two novel thiophene-containing covalent organic frameworks (TD-COF TT-COF) were first constructed served as catalysts for via indirect 2e- ORR direct WOR channels. The photocatalytic production performance can be regulated by adjusting N-heterocycle modules (pyridine triazine) COFs. Notably, no just using air raw materials, TD-COF exhibited high yields of 4060 μmol h-1 g-1 3364 deionized natural seawater, respectively. Further computational mechanism studies revealed that thiophene was primary photoreduction unit ORR, while benzene ring (linked to imine bond) central photooxidation WOR. current work exploits COFs overall provides fresh insight into creating innovative photocatalyzing synthesis.

Language: Английский

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Regulating Relative Nitrogen Locations of Diazine Functionalized Covalent Organic Frameworks for Overall H₂O₂ Photosynthesis

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(41)

Published: Aug. 26, 2023

Nitrogen-heterocycle-based covalent organic frameworks (COFs) are considered promising candidates for the overall photosynthesis of hydrogen peroxide (H2 O2 ). However, effects relative nitrogen locations remain obscured and photocatalytic performances COFs need to be further improved. Herein, a collection functionalized by various diazines including pyridazine, pyrimidine, pyrazine have been judiciously designed synthesized photogeneration H2 without sacrificial agents. Compared with pyrimidine pyrazine, pyridazine embedded in TpDz tends stabilize endoperoxide intermediate species, leading toward more efficient direct 2e- oxygen reduction reaction (ORR) pathway. Benefiting from effective electron-hole separation, low charge transfer resistance, high-efficiency ORR pathway, an excellent production rate 7327 μmol g-1 h-1 solar-to-chemical conversion (SCC) value 0.62 % has achieved TpDz, which ranks one best COF-based photocatalysts. This work might shed fresh light on rational design functional targeting photocatalysts production.

Language: Английский

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Efficient photocatalytic production of hydrogen peroxide using dispersible and photoactive porous polymers

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

Published: Oct. 28, 2023

Developing efficient artificial photocatalysts for the biomimetic photocatalytic production of molecular materials, including medicines and clean energy carriers, remains a fundamentally technologically essential challenge. Hydrogen peroxide is widely used in chemical synthesis, medical disinfection, energy. However, current industrial production, predominantly by anthraquinone oxidation, suffers from hefty penalties toxic byproducts. Herein, we report hydrogen protonation-induced dispersible porous polymers with good charge-carrier transport properties. Significant generation occurs under ambient conditions at an unprecedented rate 23.7 mmol g-1 h-1 apparent quantum efficiency 11.3% 450 nm. Combined simulations spectroscopies indicate that sub-picosecond ultrafast electron "localization" both free carriers exciton states catalytic reaction centers underlie remarkable performance polymers.

Language: Английский

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Site Engineering of Covalent Organic Frameworks for Regulating Peroxymonosulfate Activation to Generate Singlet Oxygen with 100 % Selectivity

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(43)

Published: Sept. 5, 2023

Singlet oxygen (1 O2 ) is an excellent reactive species (ROSs) for the selective conversion of organic matter, especially in advanced oxidation processes (AOPs). However, due to huge dilemma synthesizing single-site type catalysts, control and regulation 1 generation AOPs still challenging underlying mechanism remains largely obscure. Here, taking advantage well-defined flexibly tunable sites covalent frameworks (COFs), we report first achievement precisely regulating ROSs peroxymonosulfate (PMS)-based by site engineering COFs. Remarkably, COFs with bipyridine units (BPY-COFs) facilitate PMS activation via a nonradical pathway 100 % , whereas biphenyl-based (BPD-COFs) almost identical structures activate produce radicals (⋅OH SO4.- ). The BPY-COFs/PMS system delivers boosted performance degradation target pollutants from water, which ca. 9.4 times that its BPD-COFs counterpart, surpassing most reported PMS-based systems. Mechanism analysis indicated highly electronegative pyridine-N atoms on BPY-COFs provide extra adsorb terminal H PMS, resulting simultaneous adsorption O one pyridine ring, facilitates cleavage S-O bond generate .

Language: Английский

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Enaminone‐Linked Covalent Organic Frameworks for Boosting Photocatalytic Hydrogen Production

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(31)

Published: May 31, 2023

Covalent organic frameworks (COFs), possessing pre-designable structures and tailorable functionalities, are promising candidates for photocatalysis. Nevertheless, the most studied imine-linked COFs (Im-COFs) usually suffer from unsatisfactory stability photocatalytic performance. To meet this challenge, a series of highly stable enaminone-linked (En-COFs) have been synthesized afford much improved visible-light-driven hydrogen production activities, ranging 44 to 1078 times that isoreticular Im-COFs, with only difference being linkages (enaminone vs. imine) in their structures. The enhanced light-harvesting ability, facilitated exciton dissociation chemical account superior activity. Furthermore, quinoline-linked (Qu-COFs) further obtained via post-modification Im-COFs. Compared activities Qu-COFs significantly after modification, but still below those corresponding En-COFs (3-107 times). facile synthesis, excellent activity, high demonstrate platform

Language: Английский

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