We describe the encapsulation of mobile proton carriers into defect sites in nonporous coordination polymers (CPs). The proton carriers were encapsulated with high mobility and provided high proton conductivity at 150 °C under anhydrous conditions. The high proton conductivity and nonporous nature of the CP allowed its application as an electrolyte in a fuel cell. The defects and mobile proton carriers were investigated using solid-state NMR, XAFS, XRD, and ICP-AES/EA. On the basis of these analyses, we concluded that the defect sites provide space for mobile uncoordinated H3PO4, H2PO4(-), and H2O. These mobile carriers play a key role in expanding the proton-hopping path and promoting the mobility of protons in the coordination framework, leading to high proton conductivity and fuel cell power generation.

Electrochemically formed hydrogen nanobubbles at a platinum rotating disk electrode (RDE) were detected by re-oxidation charge. The dissolution time course of the hydrogen nanobubbles was measured by AFM tapping topography under open-circuit conditions at stationary platinum and gold single-crystal electrodes. The bubble dissolution at platinum was much faster than that at gold because two types of diffusion, bulk and surface diffusion, proceeded at the platinum surface, whereas surface diffusion was prohibited at the gold electrode. These findings indicated that the electrochemical reaction of normal hydrogen electrode partly proceeded heterogeneously on the three-phase boundary around the hydrogen nanobubble.

The spectroscopic behavior of rhodamine 6G (R6G) dye intercalated in layered hexaniobate K4Nb6O17 was investigated. R6G cations were intercalated into the niobate through displacement of preintercalated alkylammonium ions. Powder X-ray diffraction and elemental analysis indicated that the dye molecules were densely accommodated in the interlayer spaces of niobate. The spectroscopic behavior of intercalated R6G was characterized by humidity-dependent aggregation at room temperature. The dye molecules were present dominantly as monomers under humid conditions (93% relative humidity (RH)), while they formed dimers under relatively dry conditions (20% RH). The aggregation-deaggregation of dye occurred reversibly depending on the humidity. The reversible aggregation was not accompanied by a large alteration of the interlayer structure of the sample, because only a small amount of water was adsorbed/desorbed with a small change in the basal spacing of the intercalation compound during the humidity change.

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The dimensionless figure of merit and its efficiency for the transient response of a Π-shaped thermoelectric module are estimated according to the theory of impedance spectroscopy. The effective dimensionless figure of merit is described as a function of the product of the characteristic time to reduce the temperature and the representative angular frequency of the module, which is expressed by the thermal diffusivity and the length of the elements used. The characteristic time required for achieving a higher dimensionless figure of merit and efficiency is derived quantitatively for the transient response using the properties of a commercial thermoelectric module.

We investigated photoelectrochemical behavior of rhodamine 6G (R6G) dye intercalated in layered oxides of semiconducting hexaniobate and photochemically inert saponite clay. The R6G-clay intercalation compound generated comparable cathodic and anodic photocurrents. Photocurrent action spectra indicated that both the photocurrents were ascribed to photoexcitation of R6G monomers and dimers present in the interlayer spaces. On the other hand, the R6G-niobate intercalation compound exhibited a relatively large cathodic and small anodic photocurrents. Action spectra of the R6G-niobate system indicated that the photocurrents were generated by photoexcitation of only the R6G monomers while that the coexisting dimeric species were apparently silent. This result was explained by that the photocurrents were generated through photosensitization of the photocatalytically active semiconducting niobate layers with electron transfer from the photoexcited R6G monomers, whereas that the dimers were deactivated through dye-dye interactions.

Commercialized bulk constantan with a low dimensionless figure of merit and its film fabricated by electroplating were prepared to demonstrate the feasibility of impedance spectroscopy for estimating thermoelectric parameters. From the frequency dependence of the impedance, the resistivity and dimensionless figure of merit were directly estimated as 5.3 × 10−7 Ωm and 0.026 for the bulk and 3.8 × 10−7 Ωm and 0.0098 for the film at room temperature (302 K), respectively. We concluded that impedance spectroscopy is a suitable technique for estimating the thermoelectric parameters of any material with an apparent Seebeck coefficient.

Synthesis. All chemicals employed were obtained from commercial suppliers and used without further purification. A mixture of zinc oxide (162 mg, 2 mmol), phosphoric acid (85% solution), and water (350 l) were stirred in a mortar until the mixture become transparent. To obtain a series of coordination polymers (CPs) encapsulated phosphoric acid, the amount of the reacted excess phosphoric acid were 4.0 (2), 4.4 (3), 4.8 (4), and 5.2 mmol (5). 1,2,4-triazole (276 mg, 4 mmol) was added to the solution and the mixture was grinded for 10 min at room temperature. The obtained white powder was washed with ethanol three times, and dried at 80 °C overnight to get dry pure-phase. For single crystal neutron diffraction measurements, we prepared a large single crystal. The zinc oxide and 1,2,4-triazole were grinded in the mortar for 5 min. Phosphoric acid (85 % solution) was added to the obtained powder. After maintaining at room temperature for 1 week, the single crystal was formed (1s). Physical measurements. X-ray powder diffraction (XRPD) patterns were collected on a Rigaku RINT 2000 Ultima diffractometer with CuK radiation. Thermogravimetry analysis (TGA) was performed using a Rigaku TG8120 under flowing nitrogen with 10 K min −1 ramp rate. Inductively coupled plasma atomic emission spectroscopy (ICP-AES) and Elemental analysis (EA). ICP-AES was used to determine the amount of zinc and phosphorus by SII NanoTechnology SPS-5100. We performed calibrations by standard reference materials before the measurement. The carbon and nitrogen contents were analyzed by a high-frequency combustion-IR absorption instrument LECO IR-412