Crystalline polyoxometalate (POM)–polyethylene glycol (PEG) composites aimed as non-humidified intermediate-temperature proton conductors

Journal Article · Mon Feb 15 00:00:00 EST 2016 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2015.11.030· OSTI ID:22577768

Tsuboi, Masaki ^[1]; Hibino, Mitsuhiro; Mizuno, Noritaka ^[2]; Uchida, Sayaka ^[1]

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1. Department of Basic Sciences, School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902 (Japan)
2. Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

Crystalline polyoxometalate (POM)–polyethylene glycol (PEG) composites aimed as non-humidified intermediate-temperature proton conductors were synthesized and characterized by single crystal and powder XRD, solid state MASNMR, and TG-DTA measurements. Among the POM–PEG composites, Cs{sub 2.7}H{sub 0.3}[PW{sub 12}O{sub 40}]·1.2PEG1000 (CsHPW-PEG1000) possessed one-dimensional channels with diameters of ca. 6 and 8 Å, where PEG probably resided, and showed the best performance as a proton conductor (1.2×10{sup −5} S cm{sup −1} at 443 K). Proton conductivities of POM–PEG composites decreased by the increase in molecular weights of PEG (CsHPW-PEG12,000) or anion charges (CsHSiW-PEG1000). Variable contact time {sup 13}C-CP (cross polarization) MASNMR revealed that local mobility (i.e., segmental motion) of PEG is related to the trends in proton conductivities. These results show that amount of acidic protons (H{sup +}) is not the primary factor in proton conduction and that segmental motion of PEG assists the proton hopping among POMs in the crystal lattice of POM–PEG composites. - Graphical abstract: Non-humidified intermediate-temperature proton conduction in crystalline polyoxometalate (POM)–polyethylene (PEG) composites are assisted by the segmental motion of PEG. - Highlights: • Crystalline polyoxometalate–polyethlene glycol (PEG) composites were synthesized. • CsHPW-PEG1000 possessed one-dimensional channels and showed the highest proton conductivity. • {sup 13}C CPMASNMR revealed that segmental motion of PEG is related to the proton conduction.

• OSTI ID: 22577768
• Journal Information: Journal of Solid State Chemistry, Vol. 234; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ANIONS
CRYSTAL LATTICES
DIFFERENTIAL THERMAL ANALYSIS
MOBILITY
MOLECULAR WEIGHT
MONOCRYSTALS
PERFORMANCE
PETROLEUM RESIDUES
POLARIZATION
POLYETHYLENE GLYCOLS
POLYETHYLENES
POWDERS
PROTON CONDUCTIVITY
PROTON TEMPERATURE
PROTONS
SOLIDS
X-RAY DIFFRACTION