Proton conduction in and structure of P2O5-TiO2-CaO-Na2O sol-gel glasses

• Published in: Journal of the Korean Physical Society Vol. 70; no. 12; pp. 1054 - 1059
• Main Authors: Kim, Dae Sung, Shin, Jae Young, Ryu, Bong Ki
• Format: Journal Article
• Language: English
• Published: Seoul The Korean Physical Society 01.06.2017; Springer Nature B.V; 한국물리학회
• Subjects: Atomic properties; Chemical bonds; Differential scanning calorimetry; Fourier analysis; Fourier transforms; Functional groups; Glass; Heat measurement; Infrared spectroscopy; Mathematical and Computational Physics; Oxygen atoms; Particle and Nuclear Physics; Phosphorus pentoxide; Physics; Physics and Astronomy; Proton conduction; Relative humidity; Sol-gel processes; Theoretical; Thermodynamic properties; Titanium dioxide; Titanium oxides; X-ray diffraction; 물리학; Proton conduction; Sol-gel; Phosphate glass
• ISSN: 0374-4884; 1976-8524
• DOI: 10.3938/jkps.70.1054

Phosphate sol-gel-derived glasses in a P 2 O 5 -CaO-Na 2 O-TiO 2 system with a high TiO 2 content of up to 50 mol% were synthesized. A sol-gel method was chosen because incorporating a high percentage of titanium into the phosphate network via traditional melt-quench methods is not trivial. The structural and the thermal properties of the obtained stabilized sol-gel glasses were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and differential scanning calorimetry. The XRD results confirmed the amorphous and glassy nature of the prepared samples. The FTIR results revealed that, with the addition of TiO 2 , titanium oxide (TiO 6 ) (which likely acts as a modifier oxide) entered the network. Consequently, the number of terminal oxygen atoms increased, leading to an increase in the number of P-OH bonds. The proton conductivity of the sol-gel glass samples was as high as 0.0102 S·cm −1 at a relative humidity of 100% and a temperature of 100 ◦ C. The FTIR analysis confirmed the presence of (HPO 4 ) 2− - and (H 2 PO 4 ) − -coordinated phosphorous. These functional groups acted as a bridge in the Grotthuss proton-conduction mechanism.