Background Production of biodiesel from renewable sources such as inedible vegetable oils by enzymatic catalysis has been a hotspot but remains a challenge on the efficient use of an enzyme. COFs (Covalent Organic Frameworks) with large surface area and porosity can be applied as ideal support to avoid aggregation of lipase and methanol. However, the naturally low density limits its application. In this work, we reported a facile synthesis of core–shell magnetic COF composite (Fe3O4@COF-OMe) to immobilize RML (Rhizomucor miehei lipase), to achieve its utilization in biodiesel production. Result This strategy gives extrinsic magnetic property, and the magnetic COFs is much heavier and could disperse in water medium well, facilitating the attachment with the enzyme. The resultant biocomposite exhibited an excellent capacity of RML due to its high surface area and fast response to the external magnetic field, as well as good chemical stability. The core–shell magnetic COF-OMe structure not only achieved highly efficient immobilization and recovery processes but also maintained the activity of lipase to a great extent. RML@Fe3O4@COF-OMe performed well in practical applications, while free lipase did not. The biocomposite successfully achieved the production of biodiesel from Jatropha curcas Oil with a yield of about 70% in the optimized conditions. Conclusion Magnetic COFs (Fe3O4@COF-OMe) for RML immobilization greatly improved catalytic performance in template reaction and biodiesel preparation. The magneticity makes it easily recovered and separated from the system. This first successful attempt of COFs-based immobilized enzyme broadened the prospect of biodiesel production by COFs with some inspiration.

Covalent organic frameworks (COFs) are widely used in photocatalysis due to their periodic π–π arrays, high crystallinity, and adjustable bandgap. Herein, a new strategy for integrating polyphenyl building blocks in COFs is presented to improve the photocatalytic efficiency. To implement this strategy, a series of COFs with different numbers of phenyl groups are successfully designed and synthesized. By varying the number of phenyl units in the precursor, the COFs exhibit different bandgaps, band‐edge positions, carrier mobilities, and interfacial transfer resistances. The corresponding characterization reveals that the photocatalytic capacity of COFs increases with the number of phenyls in the basic structural unit. Further, under visible light irradiation, the COFs prepared from 1,3,5‐tris [4‐amino(1,1‐biphenyl‐4‐yl)] benzene (TABB) and 1,4‐benzenedicarboxaldehyde (BDB) (named TABB‐BDB COF) exhibit superior light‐responsive oxidase‐mimicking characteristic, which can catalyze the oxidation of 2,2′‐azino‐bis (3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS). Based on the aforementioned characteristics, TABB‐BDB COF is designed as a robust colorimetric probe for the inexpensive, highly sensitive, and rapid detection of uric acid (UA) with a linear range of 5–160 mg L−1. This study not only demonstrates COFs‐based light‐response oxidase mimicking for efficient UA detection but also provides an intelligent tactic for boosting the photocatalytic competence of COFs.

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Background: Production of biodiesel from renewable sources such as inedible vegetable oils by enzymatic catalysis has been a hotspot but remains a challenge on the efficient use of an enzyme. COFs (Covalent Organic Frameworks) with large surface area and porosity can be applied as ideal support to avoid aggregation of lipase and methanol. However, the naturally low density limits its application. In this work, we reported a facile synthesis of core-shell magnetic COF composite (Fe3O4@COF-OMe) to immobilize RML (Rhizomucor miehei lipase), to achieve its utilization in biodiesel production.Result: This strategy gives extrinsic magnetic property, and the magnetic COFs is much heavier and could disperse in water medium well, facilitating the attachment with the enzyme. The resultant biocomposite exhibited an excellent capacity of RML due to its high surface area and fast response to the external magnetic field, as well as good chemical stability. The core-shell magnetic COF-OMe structure not only achieved highly efficient immobilization and recovery processes but also maintained the activity of lipase to a great extent. RML@Fe3O4@COF-OMe performed well in practical applications, while free lipase did not. The biocomposite successfully achieved the production of biodiesel from Jatropha curcas Oil with a yield of about 70% in the optimized conditions. Conclusion: Magnetic COFs (Fe3O4@COF-OMe) for RML immobilization greatly improved catalytic performance in template reaction and biodiesel preparation. The magneticity makes it easily recovered and separated from the system. This first successful attempt of COFs-based immobilized enzyme broadened the prospect of biodiesel production by COFs with some inspiration.