Rapid and low-cost synthesis of metal–organic frameworks (MOFs) are very meaningful for their future practical application. In the present study, a Zr-based ultrastable MOF, UiO-66-NH2, was successfully synthesized by electrochemical method using metal Zr as the metal source at room temperature and atmospheric pressure. The effects of the reaction conditions, including the ratio of solvent (electrolyte), the applied voltage and different reaction time, on the crystallinity, morphology, and synthesis rate of the product were fully investigated. The results confirm that electrochemically synthesized UiO-66-NH2 under the optimized condition possesses apparent merits such as high crystallinity, uniform morphology and high porosity. Moreover, the electrochemical synthesis method of UiO-66-NH2 is promising for the large-scale and economical synthesis of nanoscale product to gramme degree. Interestingly, the resulting UiO-66-NH2 synthesized by this electrochemical method exhibits more excellent performance for the fluorescence detection of Fe3+ ions in water (detection limit of 10–8 mol/L) than that of the material prepared by solvothermal method.

Based on the inner filter effect, a luminescent Zn(ii)/Na(i) metal-organic framework (MOF) {[Zn2Na(L)(HL)2(H2O)2][OAc]·2H2O}n (1, H2L = 5-methyl-1,3-benzenedicarboxylic acid) with excellent stability was constructed for the fluorescence detection of Cu2+ ions. MOF 1 holds a 3D cationic framework in which [(OAc)2(H2O)2]n2n- anions are embedded into its 1D channels. Abundant hydrogen-bonding and π-π interactions in the MOF facilitate electron transfer from ligand-to-metal, resulting in a good luminescence peak at 412 nm and an efficient fluorescence quenching of MOF 1 in the presence of Cu2+ ions, due to the inner filter effect. The interactions between the Cu2+ ions and the OAc- anion in the channel endowed the Cu2+ ions with facile access to be adsorbed, and afforded the selective quenching of fluorescence. The MOF particles are well dispersed in water and the Cu2+ ions are pre-concentrated by adsorption, thus facilitating the determination of Cu2+ ions with a detection limit down to 0.65 μM. Our work thus paves a way for developing MOFs as an appealing platform to construct materials for environmental applications.

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Continuous and rapid synthesis of UiO-67 under mild conditions has been achieved by electrochemical methods for the first time. In the reaction system, a zirconium sheet was utilized as electrodes and a metal source for the assembly of UiO-67. High-crystalline UiO-67 with a regular tetrahedral morphology of around 1 μm was obtained within 1.5 h under the optimized solvent composition, voltage, and temperature conditions. This electrochemical synthetic method of UiO-67 in our work overcomes the shortcomings of high temperature and pressure of a traditional solvothermal method, which proposes new ideas for the large-scale and rapid synthesis of UiO-67. The UiO-67 synthesized by an electrochemical method was prepared as a UiO-67−carbon paste electrode (CPE), which exhibited a linear response to hydroquinone (HQ) in the range of 5−300 μM with a detection limit of 3.6 × 10 −9 M (S/N = 3), for the electrochemical detection of HQ. It was confirmed that UiO-67−CPE possessed excellent reusability and antiinterference ability for the detection of HQ, and its detection ability even did not change after standing for 3 months. We further tried to apply UiO-67−CPE to the practical determination of HQ in tap water and river water samples, and the results proved that the recovery rate is 97.9−104.7% in real samples.