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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 and COF‐JLU52) featuring large surface area, high crystallinity, excellent stability and photoelectric properties were designed and constructed for the first time. Remarkably, COF‐JLU51 gave an outstanding H2O2 production rate of over 4200 μmol g−1 h−1 with excellent reusability in pure water and O2 under one standard sun light, that higher than its isomorphic COF‐JLU52 and most of the reported metal‐free materials, owing to its superior generation, separation and transport of photogenerated carriers. Experimental and theoretical researches prove that the photocatalytic process undergoes a combination of indirect 2e− O2 reduction reaction (ORR) and 4e− H2O oxidation reaction (WOR). Specifically, an ultrahigh yield of 7624.7 μmol g−1 h−1 with apparent quantum yield of 18.2 % for COF‐JLU52 was achieved in a 1 : 1 ratio of benzyl alcohol and water system. This finding contributes novel, nitrogen‐rich and high‐quality tris(triazolo)triazine‐based COF materials, and also designate their bright future in photocatalytic solar transformations. [ABSTRACT FROM AUTHOR]

Photoactive conjugated microporous polymers (CMPs) as heterogeneous photocatalysts provide a sustainable alternative to classical metal‐based semiconductor photosensitizers. However, previously reported CMPs are typically synthesized through metal catalyzed coupling reactions, which bears product separation, but also increases the price of materials. Herein, a new type of sp2 carbon linked DCM‐CMPs are successfully designed and synthesized by organic base catalyzed Knoevenagel reaction using 2,6‐Dimethyl‐4H‐pyran‐4‐ylidene‐malononitrile and aromatic polyaldehydes as monomers. The new polymers feature inherent porosity, excellent stability, and fully π‐conjugated skeleton with broad visible‐light absorption. They effectively induce the synthesis of benzimidazole compounds under light irradiation, and exhibit wide substrate adaptability with outstanding recyclability. [ABSTRACT FROM AUTHOR]

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 and COF-JLU52) featuring large surface area, high crystallinity, excellent stability and photoelectric properties were designed and constructed for the first time. Remarkably, COF-JLU51 gave an outstanding H 2 O 2 production rate of over 4200 μmol g -1  h -1 with excellent reusability in pure water and O 2 under one standard sun light, that higher than its isomorphic COF-JLU52 and most of the reported metal-free materials, owing to its superior generation, separation and transport of photogenerated carriers. Experimental and theoretical researches prove that the photocatalytic process undergoes a combination of indirect 2e - O 2 reduction reaction (ORR) and 4e - H 2 O oxidation reaction (WOR). Specifically, an ultrahigh yield of 7624.7 μmol g -1  h -1 with apparent quantum yield of 18.2 % for COF-JLU52 was achieved in a 1 : 1 ratio of benzyl alcohol and water system. This finding contributes novel, nitrogen-rich and high-quality tris(triazolo)triazine-based COF materials, and also designate their bright future in photocatalytic solar transformations., (© 2024 Wiley-VCH GmbH.)

Wurtzite CuInS 2 exhibits great potential for optoelectronic applications because of its excellent optical properties and good stability. However, exploring effective strategies to simultaneously optimize its optical and photoelectrical properties remains a challenge. In this study, the bandgap of wurtzite CuInS 2 nanocrystals is successfully extended and the photocurrent is enhanced synchronously using external pressure. The bandgap of wurtzite CuInS 2 increases with pressure and reaches an optimal value (1.5 eV) for photovoltaic solar energy conversion at about 5.9 GPa. Surprisingly, the photocurrent simultaneously increases nearly 3-fold and reaches the maximum value at this critical pressure. Theoretical calculation indicates that the pressure-induced bandgap extention in wurtzite CuInS 2 may be attributed to an increased charge density and ionic polarization between the In-S atoms. The photocurrent preserves a relatively high photoresponse even at 8.8 GPa, but almost disappears above 10.3 GPa. The structural evolution demonstrates that CuInS 2 undergoes a phase transformation from the wurtzite phase ( P 6 3 mc ) to the rock salt phase ( Fm 3̄ m ) at about 10.3 GPa, which resulted in a direct to indirect bandgap transition and fianlly caused a dramatic reduction in photocurrent. These results not only map a new route toward further increase in the photoelectrical performance of wurtzite CuInS 2 , but also advance the current research of A I - B III - C VI2 materials.