Synthesis and characteristics of proton-conducting membranes based on cerium sulfophenyl phosphate and poly (2, 5-benzimidazole) by hot-pressing method

Cerium sulfophenyl phosphate (CeSPP), a novel proton conductor, is prepared starting from mixtures of m-sulfophenyl phosphonic acid (msPPA) and ammonium ceric nitrate. The CeSPP samples are combined with poly (2, 5-benzimidazole) (ABPBI) to prepare ABPBI/CeSPP composite membranes by polyphosphoric acid (PPA) hot-pressed method. The ABPBI/CeSPP composite membranes are characterized by X-ray diffraction (XRD) and infrared spectroscopy (IR). Thermogravimetric analysis (TGA) indicates thermal stability of the composite membranes below 200 °C. Scanning electron microscopy (SEM) indicates that CeSPP particles are homogenously dispersed into the composite membranes. Ce, P and S atoms are well illustrated and uniformly distributed in composite membranes via energy-dispersive X-ray spectroscopy (EDX) analysis. The proton conductivity of membrane doped in 38 wt.% CeSPP reaches 0.14 Scm−1 at 180 °C under 100% relative humidity.

► Cerium sulfophenyl phosphate (CeSPP) was synthesized. ► ABPBI/CeSPP membranes were prepared by polyphosphoric acid hot-pressed method. ► The composite membranes illustrated good thermal stability and mechanical properties. ► The membranes exhibited considerably high-proton conductivity at high temperature.