ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

A new high-temperature inorganic–organic proton conductor: lanthanum sulfophenyl phosphate

Ming-Feng Song, Zhong-Fang Li, Guo-Hong Liu, Su-Wen Wang, Xiao-Yan Yin, and Yu-Xin Wang

School of Chemical Engineering, Shandong University of Technology, Zibo 255049, China

E-mail: zhfli@sdut.edu.cn

Abstract: Lanthanum sulfophenyl phosphate (LaSPP) was synthesized by m-sulfophenyl phosphonic acid and lanthanum nitrate. UV-Vis spectrophotometry and Fourier-transform infrared spectroscopy indicate that the desired product was obtained and its elementary composition and typical layered structure were determined by energy dispersive X-ray spectroscopy and scanning electron microscopy. Transmission electron microscopy (TEM) proved its typical layered structure and X-ray diffraction spectroscopy indicated its good crystallinity and the interlayer distance of about 15.67 Å , which matches the value obtained by TEM (2.0 nm). Thermogravimetry and differential thermal analysis revealed good thermal stability of LaSPP. Proton conductivity of LaSPP was measured at different temperatures and relative humidities (RH), reaching values of 0.123 S cm^-1 at 150°C and 100 % RH. Proton transfer activation energy was 22.52 kJ mol^-1. At 160°C and 50 % RH, the conductivity was 0.096 S cm^-1. In the drying oven, the conductivity retained the value of 1.118 × 10^-2 S cm^-1. The results show that LaSPP is a highly effective inorganic-organic conductor.

Keywords: inorganic-organic proton conductor – lanthanum sulfophenyl phosphate – proton conductivity – relative humidity – proton transfer activation energy

Full paper is available at www.springerlink.com.

DOI: 10.1515/chempap-2015-0219

Chemical Papers 70 (3) 343–349 (2016)