A new anthracene-based Zr-MOF for highly efficient visible-light-driven CO2 reduction to produce formate via dual catalytic routes.

By using a controllable pillared-layer method, a novel visible-light responsive metal–organic framework (MOF) photocatalyst NNU-36 has been rationally constructed. The synthesized NNU-36 is of broad-range visible light absorption and good chemical stability which are beneficial to its application of photocatalysis. Photocatalytic experiments reveal that NNU-36 is highly efficient for Cr­(VI) reduction and dye degradation in aqueous solution under visible light irradiation. Control experiments show that the pH value is vital for Cr­(VI) reaction, and meanwhile, the use of hole scavenger of methanol promotes the photocatalytic reduction significantly. It has been also demonstrated that NNU-36 is efficient for dye degradation, in which the introduction of hydrogen peroxide (H2O2) significantly enhances the photocatalytic efficiency of dye degradation. This study illustrates that the introduction of hole scavengers or oxidants in the MOF-mediated photocatalytic reaction is a feasible approach to enhance the catalytic efficiency by suppressing the recombination of photoexcited electron–hole pairs in MOFs photocatalysts.

A new three-dimensional microporous MOF has been constructed using a highly conjugated anthracene-based ligand. The rarely occurring long-range π-stacking of the ligand in the form of a zigzag chain has been found in the MOF structure, which provides not only a new charge transport pathway with high electrical conductivity of 1.3 (±0.5) × 10(-3) S cm(-1) but also an electroluminescence property with an emission centred at 575 nm.

A dual-emitting dye@MOF composite has been synthesized by incorporating a fluorescent dye eosin Y (EY) within a UiO-type zirconium-based metal−organic framework (Zr-MOF) through a synthetic encapsulation method. The Zr-MOF prevents the aggregation of EY molecules and keeps EY molecules stably included after synthesis. As expected, an energy transfer from Zr-MOF to EY molecules occurred because of the good overlap between the emission of Zr-MOF and the absorption of EY. As a result, the obtained EY@Zr-MOF composite features a weak blue emission at 446 nm and a strong yellow emission at 553 nm. By using the relative height of the two emission peaks replacing absolute peak height as detecting signals, EY@Zr-MOF composite acts as a self-calibrating luminescent sensor for selectively detecting Fe 3+ , Cr 2 O 7 2− , and 2-nitrophenol. Furthermore, the observed fluorescence responses of the composite toward analyte are highly stable and reversible after recycling experiments. To the best of our knowledge, this is the first example of a dye@MOF-implicated self-calibrating sensor for Fe 3+ , Cr 2 O 7 2− , and 2-nitrophenol detection.

By employing a conjugated amine-functionalized dicarboxylic ligand (HL = 2,2'-diamino-4,4'-stilbenedicarboxylic acid, HSDCA-NH), we have successfully synthesized and characterized a porous and visible light responsive zirconium metal-organic framework ([ZrO(OH)(L)]·8DMF, denoted as Zr-SDCA-NH). This Zr-MOF showed good chemical stability and broad visible light absorption with an absorption edge at about 600 nm. When used as a photocatalyst, Zr-SDCA-NH exhibits visible-light activity for CO reduction with a formate formation rate of 96.2 μmol h mmol, which is higher than the series of reported amine-functionalized Zr-MOFs. Mott-Schottky measurements, photoluminescence study and photocatalytic experiments demonstrated that the Zr oxo cluster through the LMCT process and the organic ligand both contributed to the CO photoreduction. This study indicates that the combination of amino groups and highly conjugated molecules is a feasible and simple strategy to extend light absorption of the organic ligand, which is beneficial for designing a visible light responsive MOF photocatalyst.

A series of eosin Y (EY)-embedded zirconium-based metal−organic frameworks (Zr-MOFs) were prepared by utilizing the synthetic encapsulating method. By virtue of effective resonant energy transfer between Zr-MOF and EY, not only does EY@Zr-MOF exhibit dual-emissive characteristics, but also the relative intensity of their double emission is greatly tuned with increasing EY loading quantity. As a consequence, the double emission of EY@Zr-MOF presented large distinctions in location and intensity. By using the relative fluorescence intensity instead of the absolute fluorescence intensity of emission peaks as detection signals, two EY@Zr-MOFs served as built-in self-calibrated fluorescence sensors to detect pesticides, where EY@Zr-MOF realized the selective detection of nitenpyram, a kind of nicotine pesticide. These results indicate that the integration of robust Zr-MOF and fluorescence molecules provides a new research platform for pesticide sensing and recognition.

A visible light responsive MOF material has been constructed by the pillared-layer approach to conduct atom transfer radical polymerization. The as-prepared polymers show narrow molecular weight distribution and high retention of chain-end activity.

As eries of dye@MOF composites were synthesized through in situ encapsulationo fl uminous rhodamine B( RhB) molecules into ab lue-emissive zirconium-naphthalene-based metal-organic framework (Zr-MOF). The fabricated RhB@Zr-MOFc omposites exhibit tunable dual-emissive characteristics due to the process of resonante nergy transfer from Zr-MOF to RhB. Notably,o ne of the RhB@Zr-MOF composites (R@D3)e xhibited aw eak emissiona t4 20 nm and as tronge mission at 607 nm, for which the two emissions possess large distinctionsi nl ocation and intensity and can be referenced with each other in sensing analytes. By using relative fluorescence intensity insteado ft heir absolute fluorescencei ntensitya st he detection signals, R@D3s erved as ab uilt-in self-calibrated platformt os electively detect Fe 3 + and Cr 2 O 7 2À ions in water.C ompared with the pristine Zr-MOF,t he R@D3 composite showse nhanced sensing selectivity to Fe 3 + and higher sensibility to Cr 2 O 7 2À .T hiss tudy displays the advantageso fc ombining organic dyes with robust Zr-MOFsi nt uning fluorescencea nd sensing performance.