Fabricating Covalent–Organic Quantum Dots through Selective Disassembly of Hydrogen-Covalent Hybridized Organic Frameworks for Efficient and Sensitive Uranium Detection

The preparation of low-dimensional covalent–organic frameworks (COFs) is currently a hot and challenging research topic, especially for zero-dimensional (0D) COF quantum dots (COQDs). Herein, for the first time we introduce a facile and efficient approach to fabricating COQDs by selectively disassembling hydrogen-covalent hybridized organic frameworks (H–COFs). By taking advantage of the disparate stabilities between noncovalent and covalent bonds within the periodic lamellar structures of H–COFs, we disrupt the hydrogen bonds through ultrasonic treatment, resulting in the decomposition of H–COFs into COQDs with abundant functional groups, uniform size, high yield, and good stability. Notably, the as-prepared COQD-1 exhibits excellent fluorescence properties, enabling its application in the detection of low-concentration UO22+ with high sensitivity, high selectivity, and good visuality. This study not only presents a novel strategy for preparing COQDs but also highlights their potential in fluorescence-based metal ion detection.