As a Materials Chemist...

Scientific Abstract: Inorganic layered double hydroxides (LDHs) that provide effective pathways for hydroxide ion conduction at intermediate temperatures (80–140 °C) are promising materials for fully inorganic and hybrid polymer–inorganic alkaline membranes. In this study, we explore the structure–property relationships of magnesium-aluminum LDHs containing doubly and singly charged anions (CO32–, SO42–, ClO4–, Cl–, NO3–). The anions were found to affect the structure,  hydroxide conductivity, and water retention of the LDHs. At intermediate temperatures (100–140 °C), LDHs with ClO4– or NO3– anions had sustained enhancement of in-plane OH– conductivity up to 12 mS/cm. Changes in structure did not affect the hydroxide conductivity, indicating that the conductivity is dominated by OH– ions on the external surfaces of the LDH platelets. The hydroxide ion conductivities of LDHs followed a trend consistent with the lyotropic series. The connection between the lyotropic series and intermediate temperature conductivity suggests a design principle for robust LDH-based anion-exchange membranes (AEMs) for electrochemical applications. 

Scientific Abstract: Basal plane-functionalized NbS2 nanosheets were obtained using in situ photolysis to generate the coordinatively unsaturated organometallic fragment cyclopentadienyl manganese(I) dicarbonyl (CpMn(CO)2). This straight-forward, direct attachment process does not rely on defect chemistry or on intentional oxidation or reduction of the nanosheets. Under UV irradiation, a labile carbonyl ligand dissociates from the tricarbonyl complex, creating an open coordination site for bonding between the Mn atom and the electron-rich sulfur atoms on the surface of the NbS2 nanosheets. In contrast, no reaction is observed with 2H-MoS2 nanosheets under the same reaction conditions. This difference in reactivity is consistent with the electronic structure calculations, which indicate stronger bonding of the organometallic fragment to electron-poor, metallic NbS2 than to semiconducting, electron-rich MoS2. X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared (FTIR) spectroscopy, and powder X-ray diffraction (PXRD) were used to characterize the bonding between Mn and S atoms on the surface-functionalized nanosheets.  We are optimistic that the insights gained from this study can be leveraged to identify and investigate other organometallic complexes that might be effective for functionalizing the basal planes of a number of TMDs, including MoS2.