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The strategy of molecular engineering has been employed to build the structure–property–activity relationship for covalent organic frameworks (COFs) with efficient photocatalytic water splitting for hydrogen production. However, previous reports focus on the impact of molecular design on COFs' physicochemical properties, the crystallinity differences are usually ignored and related studies remain rare. Herein, we describe the preparation of a series of structurally related COFs with similar chemical compositions but have different numbers of nitrogen (N) atoms in the central aromatic ring via an efficient crystallization strategy using of 2,4,6-triformyl resorcinol (TFR). On one hand, the introduction of N atoms reduces π-π stacking interaction during the formation of framework, leading to a decrease in crystallinity. On the other hand, it contributes to enhancing the photocatalytic performance of the materials by varying the electronic structures. Consequently, our results revealed that the photocatalytic hydrogen evolution (PHE) rate is 61.22 mmol g−1 h−1 for COF-905-1N, significantly higher than COF-905-3N (40.60 mmol g−1 h−1) and COF-905 (26.23 mmol g−1 h−1). This study not only provide fundamental insights into formation mechanism of COFs, but also provide a practical approach to enhance COF-based photocatalytic performance. We synthesized three COFs (COF-905, COF-905-1N, and COF-905-3N) with varying number of nitrogen atoms, resulting in different crystallinity via molecular engineering. COF-905-1N shows the highest photocatalytic hydrogen production performance with a rate up to 61.22 mmol g−1 h−1. The water-drainage experiments also suggest the potential of COF-905-1N in the practical applications for photocatalytic hydrogen evolution. [Display omitted] • Three structurally related COFs were constructed via an efficient crystallization strategy based on the use of TFR. • The crystallinity of the resultant COFs decreases as the number of N atoms in the central benzene ring increases. • The π-π stacking between the intermediate macrocycles becomes less favorable, leading to incompact stacking of 2D layers. • COF-905-1N exhibits superior PHE performance under the combined influence of nitrogen content and crystallinity. [ABSTRACT FROM AUTHOR]

• FGFR2 was upregulated in psoriatic lesion tissues. • Inhibition of FGFR2 significantly inhibited the keratinocyte proliferation and migration. • miR-124-3p was downregulated within psoriasis and could directly target FGFR2. • miR124-3p/FGFR2 axis inhibit keratinocyte proliferation, migration, and improve the inflammatory microenvironment. Keratinocyte hyperproliferation has been regarded as a central event in psoriasis pathogenesis. Investigating the mechanisms of keratinocyte hyperproliferation might provide novel strategies for psoriasis treatment. we demonstrated that fibroblast growth factor receptor 2 (FGFR2) expression was abnormally upregulated within psoriatic lesion tissues and HaCaT cells under rIL-22 stimulation. FGFR2 silence within HaCaT cells under rIL-22 stimulation significantly inhibited the capacity of cells to proliferate and to migrate, reduced IL-17A and TNFα mRNA expression, and decreased the protein levels of FGFR2, keratin 6, keratin 16, MMP1, MMP9, p-PI3K, p-AKT and p-ERK. In contrast to FGFR2, the expression of miR-124-3p showed to be remarkably downregulated within psoriasis lesion tissue samples and rIL-22-stimulated HaCaT cells. miR-124-3p inhibited the expression of FGFR2 via direct binding to its 3'UTR. Within HaCaT cells under rIL-22 stimulation, the overexpression of miR-124-3p also suppressed the capacity of cells to proliferate and to migrate, reduced IL-17A and TNFα mRNA expression, and decreased the protein levels of FGFR2, keratin 6, keratin 16, MMP1, MMP9 and p-PI3K, p-AKT and p-ERK. More importantly, when co-transfected to HaCaT cells, FGFR2-overexpressing vector significantly attenuated the effects of miR-124-3p mimics on HaCaT cells. In conclusion, we demonstrated an miR124-3p/FGFR2 axis that might inhibit human keratinocyte proliferation, migration, and improve the inflammatory microenvironment in psoriasis. miR124-3p/FGFR2 axis could be an underlying target for psoriasis therapy, which requires further in vivo and clinical investigation. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) have gained significant attention as key photocatalysts for efficient solar light conversion into hydrogen production. Unfortunately, the harsh synthetic conditions and intricate growth process required to obtain highly crystalline COFs greatly hinder their practical application. Herein, we report a simple strategy for the efficient crystallization of 2D COFs based on the intermediate formation of hexagonal macrocycles. Mechanistic investigation suggests that the use of 2,4,6‐triformyl resorcinol (TFR) as the asymmetrical aldehyde build block allows the equilibration between irreversible enol‐to‐keto tautomerization and dynamic imine bonds to produce the hexagonal β‐ketoenamine‐linked macrocycles, the formation of which could provide COFs with high crystallinity in half hour. We show that COF‐935 with 3 wt % Pt as cocatalyst exhibit a high hydrogen evolution rate of 67.55 mmol g−1 h−1 for water splitting when exposed to visible light. More importantly, COF‐935 exhibits an average hydrogen evolution rate of 19.80 mmol g−1 h−1 even at a low loading of only 0.1 wt % Pt, which is a significant breakthrough in this field. This strategy would provide valuable insights into the design of highly crystalline COFs as efficient organic semiconductor photocatalysts. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) have gained significant attention as key photocatalysts for efficient solar light conversion into hydrogen production. Unfortunately, the harsh synthetic conditions and intricate growth process required to obtain highly crystalline COFs greatly hinder their practical application. Herein, we report a simple strategy for the efficient crystallization of 2D COFs based on the intermediate formation of hexagonal macrocycles. Mechanistic investigation suggests that the use of 2,4,6‐triformyl resorcinol (TFR) as the asymmetrical aldehyde build block allows the equilibration between irreversible enol‐to‐keto tautomerization and dynamic imine bonds to produce the hexagonal β‐ketoenamine‐linked macrocycles, the formation of which could provide COFs with high crystallinity in half hour. We show that COF‐935 with 3 wt % Pt as cocatalyst exhibit a high hydrogen evolution rate of 67.55 mmol g−1 h−1 for water splitting when exposed to visible light. More importantly, COF‐935 exhibits an average hydrogen evolution rate of 19.80 mmol g−1 h−1 even at a low loading of only 0.1 wt % Pt, which is a significant breakthrough in this field. This strategy would provide valuable insights into the design of highly crystalline COFs as efficient organic semiconductor photocatalysts. [ABSTRACT FROM AUTHOR]

• A thiol-ene-induced exfoliation of COFs into CONs was developed. • Vinylene groups in OPV units allows the addition of thiols under UV irradiation. • The degree of exfoliation can be quantitatively adjusted by varying the feed ratio. • The exfoliation exhibits an obvious increase in the charge/discharge capacity. Exfoliating insoluble bulk covalent organic frameworks (COFs) into covalent organic nanosheets (CONs) is an attractive way to improve their processability and the application performance. Herein, we report an efficient thiol-ene-induced exfoliation of oligo (phenylene vinylene) (OPV) based 2D COF-935 into CONs, which exhibits an obvious improvement in the reversible charge/discharge capacity as electrode materials for energy storage devices. The presence of vinylene groups in OPV units allows the addition of thiols under UV irradiation, which weaken the interlayer interactions for exfoliation by breaking the planarity of the layers in COFs. Furthermore, the degree of modification can be quantitatively controlled by varying the feeding ratio to obtain CONs with reasonable π-conjugation and short lithium-ion transfer distance. Specifically, the CON-UV-1 offers a nearly 90 % higher excellent cycle performance of 494 mA·h·g−1 at 1 A·g−1 after 500 cycles and outstanding rechargeability. This research thus provides a promising strategy for the chemical exfoliation of covalent organic frameworks into nanosheets and promotes their potential applications in energy storage. [ABSTRACT FROM AUTHOR]

Imine‐linked covalent organic frameworks (COFs) have been extensively studied in photocatalysis because of their easy synthesis and excellent crystallinity. The effect of imine‐bond orientation on the photocatalytic properties of COFs, however, is still rarely studied. Herein, we report two novel COFs with different orientations of imine bonds using oligo(phenylenevinylene) moieties. The COFs showed similar structures but great differences in their photoelectric properties. COF‐932 demonstrated a superior hydrogen evolution performance compared to COF‐923 when triethanolamine was used as the sacrificial agent. Interestingly, the use of ascorbic acid led to the protonation of the COFs, further altering the direction of electron transfer. The photocatalytic performances were increased to 23.4 and 0.73 mmol g−1 h−1 for protonated COF‐923 and COF‐932, respectively. This study provides a clear strategy for the design of imine‐linked COF‐based photocatalysts and advances the development of COFs. [ABSTRACT FROM AUTHOR]

Imine‐linked covalent organic frameworks (COFs) have been extensively studied in photocatalysis because of their easy synthesis and excellent crystallinity. The effect of imine‐bond orientation on the photocatalytic properties of COFs, however, is still rarely studied. Herein, we report two novel COFs with different orientations of imine bonds using oligo(phenylenevinylene) moieties. The COFs showed similar structures but great differences in their photoelectric properties. COF‐932 demonstrated a superior hydrogen evolution performance compared to COF‐923 when triethanolamine was used as the sacrificial agent. Interestingly, the use of ascorbic acid led to the protonation of the COFs, further altering the direction of electron transfer. The photocatalytic performances were increased to 23.4 and 0.73 mmol g−1 h−1 for protonated COF‐923 and COF‐932, respectively. This study provides a clear strategy for the design of imine‐linked COF‐based photocatalysts and advances the development of COFs. [ABSTRACT FROM AUTHOR]

In this study, a novel TiO 2-x /TiN@C heterojunction was prepared using a typical hydrothermal synthesis and carbon thermal reduction approach. It was employed for photocatalytic degradation of levofloxacin antibiotics, with the formation of heterostructures and the surface plasmon resonance effect from TiN and TiO 2-x playing a crucial role in enhancing the photocatalytic activity. [Display omitted] • Porous TiO 2-x /TiN@C microdisks with abundant heterointerfaces were prepared through the process of ammonium chloride-assisted nitride pyrolysis for the photocatalytic degradation of levofloxacin. • Surface plasmon resonance induced by plasmonic TiN enhances the absorption of visible light. • The broad-spectrum absorption capability contributes to the improvement of photocatalytic performance. • The synergistic effect between photocatalysis and advanced oxidation processes enhances the efficiency of levofloxacin degradation. Semiconductor photocatalysis holds great promise as a method for addressing the issue of antibiotic pollution in water. However, the wide band gap and low carrier separation rate present significant challenges that restrict the water purification efficiency of photocatalytic materials. In this study, a novel TiO 2-x /TiN@C heterojunction was prepared through a typical hydrothermal synthesis and carbon thermal reduction approach, which was utilized for the photocatalytic degradation of levofloxacin (LEV) antibiotics. TiO 2-x contains various titanium oxides, including TiO 2 , Ti 2 O 3 , and Ti 3 O 5 , and possesses a narrow band gap, enabling efficient absorption of visible light. The visible light absorption ability is further enhanced when it forms a heterojunction with plasmonic titanium nitride, which exhibits good carrier separation ability. The results demonstrated that the degradation efficiency of TiO 2-x /TiN@C for levofloxacin under visible light irradiation was significantly superior to that of TiO 2-x @C and TiN without a heterostructure. Characterization tests and mechanistic analysis have revealed that the coupling of the heterostructure with localized surface plasmon resonance (LSPR) enhances photocatalytic activity. Additionally, the combination of photocatalysis with advanced oxidation methods has exhibited excellent catalytic degradation performance. This research provides novel insights into fabricating efficient LSPR-enhanced photocatalytic systems and a comprehensive understanding of the degradation pathways for LEV. [ABSTRACT FROM AUTHOR]