Metamagnetism in Nanosheets of CoII-MOF with TN at 26 K and a Giant Hysteretic Effect at 5 K

Photocatalytic Hydrogen Evolution Based on Cobalt-Organic Framework with High Water Vapor Adsorption

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.

Exploring Magnetic XY Behavior in a Quasi-2D Anisotropic Triangular Lattice of Cu(II) by Functionalized Graphene

Study on magnetism in two-dimensional (2D) spin-lattices is advancing rapidly. In this work, phase-pure botallackite (Bo) (Cu₂(OH)₃Br), a quasi-2D S = 1/2 anisotropic triangular spin-lattice is stabilized over 2D reduced graphene oxide (rGO) nanosheets via simple oxidation-reduction reaction chemistry. In comparison to polycrystalline Bo, such an anchoring resulted in the oriented growth of Bo crystallites in the Bo-rGO system. The Bo-rGO nanocomposite was found to be magnetically active with a Néel transition at ∼8.9 K, crossing over to possible XY anisotropy at ∼5 K-as revealed by complementary dc and ac susceptibility measurements-an unprecedented observation in the field assigned to an interfacial effect. This work demonstrates the potential usage of nonmagnetic 2D functionalized graphene to significantly modulate the magnetic properties of 2D spin-lattices.

Embedding S = 1/2 Kagome-like Lattice in Reduced Graphene Oxide

An elegant platform to explore frustrated magnetism is the kagome spin lattice. In this work, clinoatacamite, a naturally occurring S = 1/2 kagome-like antiferromagnetic insulator, is synthesized in water at ambient pressure for the first time from a cuprous chloride (CuCl) precursor whereby Cu(I) was spontaneously oxidized to Cu(II) in the form of clinoatacamite [Cu₂(OH)₃Cl] with a simultaneous reduction of graphene oxide (GO) to reduced graphene oxide (rGO) in one pot. A stable nanocomposite of phase-pure clinoatacamite nanocrystals embedded in the rGO matrix was isolated. The clinoatacamite-rGO nanocomposite was determined to be magnetically active with a markedly enhanced coercive field of ∼2500 Oe at 5 K as well as electronically active with a conductivity value of ∼200 S·m^-1 at 300 K. Our results illustrate an avenue of combining exotic magnetic and electronic lattices without impeding their individual characteristics and synergistically generating a new class of magnetic semiconductors.

A novel nitrogen heterocyclic ligand-based MOF: synthesis, characterization and photocatalytic properties

The synthesis of novel coordination polymers that are highly efficient, stable and reusable photocatalysts for the degradation of MB dye.