A non-luminescent NH ₂ -MOF-76(Eu) exhibits selective fluorescence recovery for sensing anthrax biomarker DPA through a single-crystal to single-crystal phase transition.

2D materials have strong intermolecular van der Waals forces, and 2D superlattice heterostructures have exhibited many dramatic photo-electrochemical properties for energy conversion and storage. Herein, based on the excellent properties of reduced graphene and superlattice structures, we constructed a 2D flexible superlattice polyoxometalate/rGO heterojunction with enhanced electron–hole separation via interfacial self-assembly engineering to further fabricate DSSCs based on the heterojunction-modified photoanode, which exhibited good electron transport properties. Selecting two kinds of Dawson POMs (P₂W₁₅V₃, P₂W₁₈ and the corresponding heteropoly blue) as the research object, the polyoxometalate superlattice structure was obtained by the self-assembly strategy, and characterized by IR, UV-Vis, XRD, EDX and XPS. The TEM and AFM results indicated that the monolayer POM superlattice structure and superlattice polyoxometalate/rGO heterojunction were successfully obtained. The superlattice P₂W₁₈(HPB)/rGO heterojunction was introduced into the DSSCs photoanode, and electrochemical tests indicated that the superlattice polyoxometalate/rGO heterojunction improved the electron–hole separation rate, inhibited the electron recombination, and improved the photoelectric conversion efficiency to 8.09%. The 2D superlattice heterojunction remarkably improved the electrochemical performances of the energy storage and conversion systems.

Developing high−efficiency membrane materials for the rapid removal of organic dyes is crucial but remains a challenge. Polyoxometalates (POMs) clusters with anionic structures are promising candidates for the removal of cationic dyes via electrostatic interactions. However, their shortcomings, such as their solubility and inability to be mass−produced, hinder their application in water pollution treatment. Here, we propose a simple and green strategy utilizing the room temperature stirring method to mass produce nanoscale polyoxometalate−based metal−organic frameworks (POMOFs) with porous rhomboid−shaped dodecahedral and hexagonal prism structures. The products were labeled as POMOF1 (POMOF-PW₁₂) and POMOF2 (POMOF-PMo₁₂). Subsequently, a series of x wt% POMOF1/PAN (x = 0, 3, 5, and 10) nanofiber membranes (NFMs) were prepared using electrospinning technology, where polyacrylonitrile (PAN) acts as a “glue” molecule facilitating the bonding of POMOF1 nanoparticles. The as−prepared samples were comprehensively characterized and exhibited obvious water stability, as well as rapid selective adsorption filtration performance towards cationic dyes. The 5 wt% POMOF1/PAN NFM possessed the highest removal efficiency of 96.7% for RhB, 95.8% for MB, and 86.4% for CV dyes, which realized the selective separation over 95% of positively charged dyes from the mixed solution. The adsorption mechanism was explained using FT−IR, SEM, Zeta potential, and adsorption kinetics model, which proved that separation was determined via electrostatic interaction, hydrogen bonding, and π–π interactions. Moreover, the POMOF1/PAN membrane presented an outstanding recoverable and stable removal rate after four cycles. This study provides a new direction for the systematic design and manufacture of membrane separation materials with outstanding properties for contaminant removal.