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 UO2 2+ 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.