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The facile solvent-free synthesis of several known metal thiophosphates was accomplished by a chemical exchange reaction between anhydrous metal chlorides and elemental phosphorus with sulfur, or combinations of phosphorus with molecular P2S5 at moderate 500 °C temperatures. The crystalline products obtained from this synthetic approach include MPS3 (M = Fe, Co, Ni) and Cu3PS4. The successful reactions benefit from thermochemically favorable PCl3 elimination. This solvent-free route performed at moderate temperatures leads to mixed anion products with complex heteroatomic anions, such as P2S64−. The MPS3 phases are thermally metastable relative to the thermodynamically preferred separate MPx/ MSy and more metal-rich MPxSy phases. The micrometer-sized M-P-S products exhibit room-temperature optical and magnetic properties consistent with isolated metal ion structural arrangements and semiconducting band gaps. The MPS3 materials were examined as electrocatalysts in hydrogen evolution reactions (HER) under acidic conditions. In terms of HER activity at lower applied potentials, the MPS3 materials show the trend of Co > Ni >> Fe. Extended time constant potential HER experiments show reasonable HER stability of ionic and semiconducting MPS3 (M = Co, Ni) structures under acidic reducing conditions. 

Cyclic voltammetry was applied to investigate the permselective properties of electrode-supported ion-exchange polymer films intended for use in future molecular-scale spectroscopic studies of bipolar membranes. The ability of thin ionomer film assemblies to exclude mobile ions charged similarly to the polymer (co-ions) and accumulate ions charged opposite to the polymer (counterions) was scrutinized through use of the diffusible redox probe molecules [Ru(NH₃)₆]³⁺and [IrCl₆]²⁻. With the anion exchange membrane (AEM) phase supported on a carbon disk electrode, bipolar junctions formed by addition of a cation exchange membrane (CEM) overlayer demonstrated high selectivity toward redox ion extraction and exclusion. For junctions formed using a Fumion^®AEM phase and a Nafion^®overlayer, [IrCl₆]²⁻ions exchanged into Fumion^®prior to Nafion^®overcoating remained entrapped and the Fumion^®excluded [Ru(NH₃)₆]³⁺ions for durability testing periods of more than 20 h under conditions of interest for eventualin situspectral measurements. Experiments with the Sustainion^®anion exchange ionomer uncovered evidence for [IrCl₆]²⁻ion coordination to pendant imidazolium groups on the polymer. A cyclic voltammetric method for estimation of the effective diffusion coefficient and equilibrium extraction constant for redox active probe ions within inert, uniform density electrode-supported thin films was applied to examine charge transport mechanisms. 

Behavior of nanoconfined water in porous materials has important implications for the development of advanced water purification and storage. In the current study, the kinetics of water sorption from the vapor phase into a metal organic nanotube ((C 4 N 2 H 6 )[(UO 2 )(C 4 O 4 NH 5 )(C 4 O 4 NH 6 )]·2H 2 O (UMON)) are investigated with varying relative humidity. The UMON compound contains nanoconfined water molecules arranged in an ice-like array along the length of its one-dimensional pore and exhibits complete specificity to liquid water. Total hydration of the material is observed upon exposure to relative humidity of 60% or higher. Water uptake curves are modeled as diffusion and irreversible condensation in the pore, which leads to a modeled diffusion coefficient of (1.2 ± 0.6) × 10 −12 cm 2 s −1 for water in UMON nanochannels. This value is much lower than observed for other porous material and is most similar to water diffusivity in low-density amorphous ice. In addition, on exposure to various solvent vapors, the UMON material maintained specificity for water in the gas phase.