A scalable membrane electrode assembly architecture for efficient electrochemical conversion of CO to formic acid.

The electrochemical reduction of carbon dioxide to formic acid is a promising pathway to improve CO utilization and has potential applications as a hydrogen storage medium. In this work, a zero-gap membrane electrode assembly architecture is developed for the direct electrochemical synthesis of formic acid from carbon dioxide. The key technological advancement is a perforated cation exchange membrane, which, when utilized in a forward bias bipolar membrane configuration, allows formic acid generated at the membrane interface to exit through the anode flow field at concentrations up to 0.

Dodecagonal quasicrystals of oil-swollen ionic surfactant micelles.

A delicate balance of noncovalent interactions directs the hierarchical self-assembly of molecular amphiphiles into spherical micelles that pack into three-dimensional periodic arrays, which mimic intermetallic crystals. Herein, we report the discovery that adding water to a mixture of an ionic surfactant and -decane induces aperiodic ordering of oil-swollen spherical micelles into previously unrecognized, aqueous lyotropic dodecagonal quasicrystals (DDQCs), which exhibit local 12-fold rotational symmetry and no long-range translational order. The emergence of these DDQCs at the nexus of dynamically arrested micellar glasses and a periodic Frank-Kasper (FK) σ phase approximant sensitively depends on the mixing order of molecular constituents in the assembly process and on sample thermal history.

Aqueous Lyotropic Mesophase Behavior of Gemini Dicarboxylate Surfactants Swollen with -Decane.

We report detailed small-angle X-ray scattering (SAXS) studies of the impact of variable -decane loadings on the lyotropic liquid crystalline (LLC) phase behaviors of homologous bis(tetramethylammonium) gemini didecanoate surfactants , which derive from dimerizing decanoic acid through its α-carbon with hydrocarbyl linkers -(CH)- where = 3, 4, 5, and 6. amphiphiles with = 3 or 5 exhibit a strong propensity to form normal double gyroid (G) LLC network mesophases over wide surfactant hydration ranges, as compared to homologues with = 4 or 6. On swelling aqueous LLC mesophases with up to 35 wt % -decane, we demonstrate that odd-carbon linked surfactants ( = 3 or 5) form G and normal double diamond (D) phases over wide water concentration windows with = 22-100 °C.

Micellar Mimicry of Intermetallic C14 and C15 Laves Phases by Aqueous Lyotropic Self-Assembly.

Concentration-dependent supramolecular self-assembly of amphiphilic molecules in water furnishes a variety of nanostructured lyotropic liquid crystals (LLCs), which typically display high symmetry bicontinuous network and discontinuous micellar morphologies. Aqueous dispersions of soft spherical micelles derived from small molecule amphiphile hydration typically pack into exemplary body-centered cubic and closest-packed LLCs. However, investigations of hydrated mixtures of the ionic surfactant tetramethylammonium decanoate loaded with 40 wt % n-decane (TMADec-40) revealed the formation of a high symmetry bicontinuous double diamond LLC, as well as cubic C15 and hexagonal C14 Laves LLC phases that mirror the MgCu and MgZn intermetallic structure types, respectively.

Linker Length-Dependent Control of Gemini Surfactant Aqueous Lyotropic Gyroid Phase Stability.

Network-phase lyotropic liquid crystals (LLCs) derived from the water-directed self-assembly of small molecule amphiphiles comprise a useful class of soft nanomaterials, with wide-ranging applications in structural biology and membrane science. However, few known surfactants enable access to these mesophases over wide temperature and amphiphile concentration phase windows. Recent studies have demonstrated that gemini ("twin tail") dicarboxylate surfactants, in which alkyl carboxylates are covalently linked near the headgroups by a hydrophobic bridge, exhibit increased propensities to form double gyroid network phase LLCs.