Structure–property–activity relationships in a pyridine containing azine-linked covalent organic framework for photocatalytic hydrogen evolution

Haase, Frederik; Banerjee, Tanmay; Savaşçı, Gökçen; Ochsenfeld, Christian; Lotsch, Bettina V.

doi:10.1039/c7fd00051k

Cited by 109 publications

(82 citation statements)

References 25 publications

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“…triethanolamine as a sacrificial donor and a platinum cocatalyst. 35,36 Recently, Thomas and coworkers described a diacetylene functionalized COF with good hydrogen evolution activity. 37 Kurongot and Banerjee reported a cadmium sulfide-COF composite material with a higher hydrogen evolution rate of 3.68 mmol g -1 h -1 using lactic acid as the sacrificial agent, 32 although the COF was the minor component in that composite (90 wt.…”

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confidence: 99%

Sulfone-containing covalent organic frameworks for photocatalytic hydrogen evolution from water

et al. 2018

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Nature uses organic molecules for light harvesting and photosynthesis but most man-made water splitting catalysts are inorganic semiconductors. Organic photocatalysts, while attractive because of their synthetic tunability, tend to have low quantum efficiencies for water splitting. Here we present a crystalline covalent organic framework (COF) based on a benzobis(benzothiophene sulfone) moiety that shows a much higher activity for photochemical hydrogen evolution than its amorphous or semi-crystalline counterparts. The COF is stable under long-term visible irradiation and shows steady photochemical hydrogen evolution with a sacrificial electron donor for at least fifty hours. We attribute its high quantum efficiency of FS-COF to its crystallinity, its strong visible light absorption, and its wettable, hydrophilic 3.2 nm mesopores. These pores allow the framework to be dye sensitized, leading to a further 61% enhancement in the hydrogen evolution rate up to 16.3 mmol g-1 h-1. The COF also retained its photocatalytic activity when cast as a thin film onto a support. Photocatalytic solar hydrogen production-or water splitting-offers an abundant clean energy source for the future. The use of dispersed, powdered photocatalysts or thin catalyst films is attractively simple, but so far, no catalyst satisfies the combined requirements of cost, stability and solar-to-hydrogen efficiency. Since the first report of TiO2 as a photocatalyst, 1 many inorganic semiconductors have been explored for water splitting, both in photoelectrochemical cells and as photocatalyst suspensions. 2-4 Recently, organic semiconductors have emerged as promising materials for photocatalytic hydrogen and oxygen evolution. 5-7 Poly(p-phenylene) was first reported as a photocatalyst for hydrogen evolution in 1985, 8,9 but its activity was poor and limited to the ultraviolet spectrum. Since then, more active organic materials have been reported as visible light photocatalysts for hydrogen production using sacrificial donors. This started with carbon nitrides 5,10 followed by poly(azomethine)s, 11 conjugated microporous polymers (CMPs), 6,12,13 linear conjugated polymers, 12,14-16 and covalent triazine-based frameworks (CTFs). 17-19 Carbon nitrides were further developed into hybrid systems that facilitate overall water splitting to produce both hydrogen and oxygen, for example by including metal co-catalysts. 20 CMPs were also claimed to exhibit overall photocatalytic water splitting. 21 However, while it is possible to tune semiconductor properties such as band gap by modular copolymerization strategies, 6 organic materials such as carbon nitrides, conjugated polymers and CTFs lack long-range order: they are amorphous or semi-crystalline. 17,22 This lack of order might limit the transport of photoactive charges to the catalyst surface. 23 More generally, it is challenging to construct atomistic structure-property relationships for materials where the three-dimensional architecture is poorly defined. Covalent organic frameworks (COFs) 24-26 are a cla...

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Sulfone-containing covalent organic frameworks for photocatalytic hydrogen evolution from water

et al. 2018

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“…Subsequently, they prepared pyridine-containing COFs for hydrogen production and tested whether nitrogen on phenyl rings can enhance the photocatalytic functions of polymers. [66] PTPÀ COF showed a very low HER (84 μmol h À 1 g À 1 ) compared to those of high-nitrogen-content COFs, owing to irregular π-stacking of pyridine in the backbone, which results in low crystallinity for a polymer. Later, the same groups reported the insertion of tetra-alkynyl groups between pyrene building blocks and that substituted phenylene units can enhance the photocatalytic activities of polymers.…”

Section: Covalent Organic Frameworkmentioning

confidence: 99%

“…The resultant N3−COF exhibited a high HER of 1,703 μmol h −1 g −1 because of its structural and optoelectronic properties resulting from the rational design of the molecular structure. Subsequently, they prepared pyridine‐containing COFs for hydrogen production and tested whether nitrogen on phenyl rings can enhance the photocatalytic functions of polymers . PTP−COF showed a very low HER (84 μmol h −1 g −1 ) compared to those of high‐nitrogen‐content COFs, owing to irregular π‐stacking of pyridine in the backbone, which results in low crystallinity for a polymer.…”

Section: Photocatalysts Based On Triazine Frameworkmentioning

confidence: 99%

Recent Advances in Visible‐Light‐Driven Hydrogen Evolution from Water using Polymer Photocatalysts

2020

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Efficient polymer photocatalysts that mimic natural photosynthesis to generate H 2 through the visible-light-promoted splitting of water are ideal systems for the conversion of solar energy into usable fuel with high energy density and in an environmentally friendly manner. In this article, we review recent reports on donor-acceptor-based π-conjugated polymers as photocatalysts, including conjugated linear polymers, microporous polymers, triazine frameworks, covalent organic frameworks, polymer dots, and other related organic polymers, which show superior photocatalytic activity and robust stability under visible-light irradiation, for hydrogen production. Moreover, their syntheses and material design strategies, photophysical properties, proposed mechanisms, and applications are systematically summarized. Finally, recent research on and challenges related to organic polymer photocatalysts are discussed. This minireview will help readers to more easily understand the recent advances in and future direction of this field.

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“…The above study suggests that with the increase of N containing in the central core of COFs the photocatalytic activity is increased so further they tried to introduced N atom in the peripheral unit of COF also [20]. They introduced pyridine containing azine-linked COFs by solvothermal process between PTP-CHO and hydrazine hydrate (Figure 4).…”

Section: Covalent Organic Frameworkmentioning

confidence: 99%

Visible Light–Driven Hydrogen Production by Carbon based Polymeric Materials

Pati¹,

In²,

Tian³

2018

Visible-Light Photocatalysis of Carbon-Based Materials

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Converting solar energy into storable solar fuels such as H 2 from earth abundant sourcewater-is a nice approach to find the solution of energy crisis and environmental protection. There are two half reactions; first, water oxidation into oxygen and proton and followed by proton reduction led to H 2 evolution from water. After two decades of continuous attempts, there have been several efficient water oxidation photocatalysts introduced, whereas the proton reduction photocatalyst were relatively less explored. Major portion of reported photocatalysts for proton reduction are mainly derived from either noble metals or precious metals. Carbon-based organic photocatalysts have become attractive recently. These organic materials have several advantages like light weight, cheap, well-defined structure-property relationship and the most attractive one is better batch to batch reproducibility. Here, the reported organic photocatalysts and their performance are summarized which in fact help others to get an idea about ongoing progress in this area of research and to understand the basic designing principle for efficient photocatalysts for fuel production.

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Structure–property–activity relationships in a pyridine containing azine-linked covalent organic framework for photocatalytic hydrogen evolution

Cited by 109 publications

References 25 publications

Sulfone-containing covalent organic frameworks for photocatalytic hydrogen evolution from water

Sulfone-containing covalent organic frameworks for photocatalytic hydrogen evolution from water

Recent Advances in Visible‐Light‐Driven Hydrogen Evolution from Water using Polymer Photocatalysts

Visible Light–Driven Hydrogen Production by Carbon based Polymeric Materials

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