Well‐Designed Highly Conjugated Covalent Organic Frameworks as Light Responsive Oxidase Mimic for Effective Detection of Uric Acid

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.