RESUMEN
Photocatalytic hydrogen evolution is desired to effectively alleviate the serious crisis of energy and the environment, and the utilization of low-cost photocatalysts, especially cobalt-based MOF catalysts, is meaningful, but rarely investigated. Herein, through a self-assembly strategy, we synthesized a Co clusters-based MOF (Co3-XL) by the ligand N,N'-bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxdiimide bi(1,2,4-triazole), containing abundant carbonyl O atoms in the channels of the 3D skeleton, and a large porosity of 50.7%. The as-synthesized MOF can be stable in the pH range of 3-10 and shows a narrow band gap of 1.82 eV. Furthermore, its maximum amount of water absorption can reach 192 cm3/g. Under irradiation of simulated solar light, the rate of hydrogen evolution is 23.05 µmol·h-1·g-1 among 12 h with the presence of co-catalyst Pt and photosensitizer RhB. The reaction mechanism has been probed by the transient photocurrent response and steady-state photoluminescence spectra. Therefore, as a narrow band gap photocatalyst, the cobalt clusters-based MOF (Co3-XL) has potential applications for hydrogen evolution from water.
RESUMEN
Two isostructural 2D MOFs ([Ln7(CDA)6(HCOO)3(µ3-OH)6(H2O)8] n, abbreviated as 1-Gd and 2-Dy) were successfully synthesized under solvothermal conditions. The self-assembly of lanthanide(III) nitrate and 1,1'-cyclopropane-dicarboxylic acid (H2CDA) resulted in wheel-like Ln18 cluster second building units (SBU), which are further linked to six neighboring wheels to generate a 2D ordered honeycomb array. Both 1-Gd and 2-Dy exhibit high thermal stability and decompose above 330 °C. Moreover, they have good solvent stability in ten common solvents and pH stability with pH values from 1 to 13. Magnetic studies reveal that 1-Gd exhibits weak antiferromagnetic coupling between adjacent Gd3+ ions and has a large magnetocaloric effect of 47.30 J kg-1 K-1 (Δ H = 7.0 T at 2 K), while 2-Dy shows ferromagnetic interaction between adjacent Dy3+ ions. Interestingly, 1-Gd and 2-Dy can catalyze the cycloaddition of CO2 to epoxides under mild conditions and can be reused at least five rounds with negligible loss of catalytic performance.
RESUMEN
Benzene derivatives are seriously harmful to environment and human health, and sensitively detecting these compounds is of great significance but is a challenge. Hence, we designed and synthesized two luminescent lanthanide-organic frameworks, [{Ln(SIP)(H2O)4}]n, [Ln = Tb (1), Eu (2)], with high solvent and pH stability, which can be used as luminescent probes to detect toluene and benzaldehyde among various reagents, and the detection limit can reach up to 10-7 mol L-1 for toluene, and 10-6 mol L-1 for benzaldehyde. Regenerated experimental results indicate that both 1 and 2 can be used for at least five cycles with high precision. To the best of our knowledge, this is the first example of the two-dimensional regenerable luminescent sensor for toluene and benzaldehyde through luminescent quenching.