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Proton‐Conductive Membranes Doped with Orthophosphoric Acid Based on Inorganic–Organic Hybrid Materials
Author(s) -
Huang Sheng Jian,
Lee Hoi Kwan,
Lee Yong Su,
Kang Won Ho
Publication year - 2005
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2005.00621.x
Subject(s) - membrane , phosphoric acid , conductivity , relative humidity , thermal stability , hybrid material , proton , scanning electron microscope , amorphous solid , materials science , doping , infrared spectroscopy , analytical chemistry (journal) , sol gel , chemical engineering , differential scanning calorimetry , nuclear chemistry , chemistry , composite material , nanotechnology , crystallography , chromatography , organic chemistry , biochemistry , physics , optoelectronics , quantum mechanics , engineering , metallurgy , thermodynamics
A series of proton‐conductive inorganic–organic hybrid membranes doped with phosphoric acid (H 3 PO 4 ) have been prepared by the sol–gel process with 3‐glycidoxypropyltrimethoxysilane (GPTMS), 3‐aminopropyltriethoxysilane (APTES), and tetraethoxysilane (TEOS) as precursors. High proton conductivity of 3.0 × 10 −3 S/cm with a composition of 50TEOS–30GPTMS–20APTES–50H 3 PO 4 was obtained at 120°C under 50% relative humidity (RH). The differential thermal analysis curve showed that thermal stability of membrane is significantly enhanced by the presence of an SiO 2 framework up to 250°C. X‐ray ray diffraction revealed that the gels were amorphous. Infrared spectra showed a good complexation of H 3 PO 4 in the matrix. The porous hybrid membrane, characterized by scanning electron microscopy, shows humidity‐dependent conduction, and the conductivity under 75% relative humidity was significantly improved by addition of APTES due to the increase in the concentration of the defective site in the hybrid matrix.