Covalent organic frameworks with high quantum efficiency in sacrificial photocatalytic hydrogen evolution

Nature Communications, Journal Year: 2022, Volume and Issue: 13(1)

Published: April 29, 2022

Abstract Organic semiconductors offer a tunable platform for photocatalysis, yet the more difficult exciton dissociation, compared to that in inorganic semiconductors, lowers their photocatalytic activities. In this work, we report charge carrier lifetime is dramatically prolonged by incorporating suitable donor-acceptor (β-ketene-cyano) pair into covalent organic framework nanosheet. These nanosheets show an apparent quantum efficiency up 82.6% at 450 nm using platinum as co-catalyst H 2 evolution. Charge kinetic analysis and femtosecond transient absorption spectroscopy characterizations verify these modified have intrinsically lower binding energies longer-lived carriers than corresponding without unit. This work provides model gaining insight nature of short-lived active species polymeric photocatalysts.

Language: Английский

---

A Crystalline Partially Fluorinated Triazine Covalent Organic Framework for Efficient Photosynthesis of Hydrogen Peroxide

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(19)

Published: March 1, 2022

A partially fluorinated, metal-free, imine-linked two-dimensional triazine covalent organic framework (TF50 -COF) photocatalyst was developed. Fluorine (F)-substituted and nonsubstituted units were integrated in equimolar amounts on the edge aromatic units, where they mediated two-electron O2 photoreduction. F-substitution created an abundance of Lewis acid sites, which regulated electronic distribution adjacent carbon atoms provided highly active sites for adsorption, widened visible-light-responsive range catalyst, while enhancing charge separation. Varying proportion F maximized interlayer interactions TF50 -COF, resulting improved crystallinity with faster carrier transfer robust photostability. The -COF catalyst demonstrates high selectivity stability photoreduction into H2 , a yield rate 1739 μmol h-1 g-1 remarkable apparent quantum efficiency 5.1 % at 400 nm, exceeding performance previously reported nonmetal COF-based photocatalysts.

Language: Английский

---

Computation-based regulation of excitonic effects in donor-acceptor covalent organic frameworks for enhanced photocatalysis

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

Published: May 29, 2023

The strong excitonic effects widely exist in polymer-semiconductors and the large exciton binding energy (Eb) seriously limits their photocatalysis. Herein, density functional theory (DFT) calculations are conducted to assess band alignment charge transfer feature of potential donor-acceptor (D-A) covalent organic frameworks (COFs), using 1,3,5-tris(4-aminophenyl)triazine (TAPT) or 1,3,5-tris(4-aminophenyl)benzene (TAPB) as acceptors tereph-thaldehydes functionalized diverse groups donors. Given discernable D-A interaction strengths pairs, Eb can be systematically regulated with minimum TAPT-OMe. Guided by these results, corresponding COFs synthesized, where TAPT-OMe-COF possesses best activity photocatalytic H2 production trend other is associated that calculated for pairs. In addition, further alkyne cycloaddition imine linkage greatly improves stability resulting TAPT-OMe-alkyne-COF a substantially smaller exhibits ~20 times higher than parent COF.

Language: Английский

---

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

---

Advanced porous adsorbents for radionuclides elimination

EnergyChem, Journal Year: 2023, Volume and Issue: 5(4), P. 100101 - 100101

Published: Feb. 14, 2023

Language: Английский

---

Linkage Microenvironment of Azoles‐Related Covalent Organic Frameworks Precisely Regulates Photocatalytic Generation of Hydrogen Peroxide

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(36)

Published: July 18, 2023

Artificial H2 O2 photosynthesis by covalent organic frameworks (COFs) photocatalysts is promising for wastewater treatment. The effect of linkage chemistry COFs as functional basis to photoelectrochemical properties and photocatalysis remains a significant challenge. In this study, three kinds azoles-linked including thiazole-linked TZ-COF, oxazole-linked OZ-COF imidazole-linked IZ-COF were successfully synthesized. More accessible channels charge transfer constructed in TZ-COF via the donor-π-acceptor structure between thiazole pyrene linker, leading efficient suppression photoexcited recombination. Density theory calculations support experimental studies, demonstrating that more favorable formation *O2 intermediate production than oxazole imidazole linkages. real active sites located at benzene ring fragment unit azole linkage.

Language: Английский

---

2D/2D S-scheme heterojunction with a covalent organic framework and g-C3N4 nanosheets for highly efficient photocatalytic H2 evolution

CHINESE JOURNAL OF CATALYSIS (CHINESE VERSION), Journal Year: 2022, Volume and Issue: 43(10), P. 2592 - 2605

Published: Jan. 1, 2022

Language: Английский

---

The emerging covalent organic frameworks (COFs) for solar-driven fuels production

Coordination Chemistry Reviews, Journal Year: 2021, Volume and Issue: 446, P. 214117 - 214117

Published: July 21, 2021

Language: Английский

---

Structure–performance correlation guided applications of covalent organic frameworks

Materials Today, Journal Year: 2022, Volume and Issue: 53, P. 106 - 133

Published: Feb. 25, 2022

Language: Английский

---

Rational Modification of Two-Dimensional Donor–Acceptor Covalent Organic Frameworks for Enhanced Visible Light Photocatalytic Activity

ACS Applied Materials & Interfaces, Journal Year: 2021, Volume and Issue: 13(23), P. 27041 - 27048

Published: June 7, 2021

Covalent organic frameworks (COFs) are promising crystalline materials for photocatalytic solar- to hydrogen-energy conversion due the tunable chemical structures and energy band gaps. Herein, we report a modification strategy improving activity of COFs. A benzene-1,3,5-tricarbaldehyde (BT)- benzothiadiazole derivative-based two-dimensional donor–acceptor (D-A) COF, denoted as BT-COF, were fabricated further modified by using an alternative electron-donating unit, 2-hydroxybenzene-1,3,5-tricarbaldehyde (HBT), polycondensation reaction, yielding HBT-COF with enhanced internal D-A effect hydrophilicity. Interestingly, H2 production rate reaches 19.00 μmol h–1, which is 5 times higher than that BT-COF (3.40 h–1) under visible light irradiation. The increase in rationally attributed finely tuned levels improved wettability, turn leads broadened absorption, efficient photoinduced charge separation transfer, interactions between COF catalyst reaction substrates. present results demonstrate subtle structural can significantly modulate structure interfacial property, thus providing feasible optimization COF-based systems.

Language: Английский

---