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A series of 2D covalent organic frameworks with hexagonal and quadrilateral pores were constructed via in situ salphen or metal salphen formation.

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Dual‐atom catalysts (DAC) are deemed as promising electrocatalysts due to the abundant active sites and adjustable electronic structure, but the fabrication of well‐defined DAC is still full of challenges. Herein, bonded Fe dual‐atom catalysts (Fe2DAC) with Fe2N6C8O2 configuration were developed through one‐step carbonization of a preorganized covalent organic framework with bimetallic Fe chelation sites (Fe2COF). The transition from Fe2COF to Fe2DAC involved the dissociation of the nanoparticles and the capture of atoms by carbon defects. Benefitting from the optimized d‐band center and enhanced adsorption of OOH* intermediates, Fe2DAC exhibited outstanding oxygen reduction activity with a half‐wave potential of 0.898 V vs. RHE. This work will guide more fabrication of dual‐atom and even cluster catalysts from preorganized COF in the future.

Photoresponsive self-healing polymer gels have great potential in the fields of optical information storage, artificial intelligence, and wearable flexible devices. Herein, a series of photoresponsive self-healing gels based on dynamic imine bonds are synthesized in which the photoresponsive functions are achieved by the incorporation of the chromophore 1,2-bis(5′-formyl-2′-methylthien-3′-yl)perfluorocyclopentene (DEA) and the fluorophore 2,5-dimethoxybenzene-1,4-diformaldehyde derivatives (DBD) through the Schiff base reactions between DEA/DBD and aminopropylmethylsiloxane-dimethylsiloxane copolymers. The gels show ultrafast photoresponsive ability with the transition from yellow to blue within 10 s under 254 nm UV-Vis and subsequent color restoration within 20 s under visible light, derived from the fast ring-closure and -opening transition of DEA. Interestingly, the molecular states of DEA have influence on the on-off intensity of the fluorescence. The gels with ring-opened DEA show stronger blue fluorescence than the ones with ring-closed DEA. In addition, the cross-linked dynamic imine bond enables the gels to self-heal quickly, and the wound disappears within 10 min without any external stimuli.