Nafion/<scp>SiO<sub>2</sub></scp>@<scp>TiO<sub>2</sub></scp>‐palygorskite membranes with improved proton conductivity
Noura Thmaini, Khaled Charradi, Zakarya Ahmed, Pîlar Aranda, R. Chtourou
Abstract
Abstract This work deals with the synthesis of SiO 2 @TiO 2 supported palygorskite fibers and their use as a filler for proton exchange membrane fuel cells in order to improve their performance. SiO 2 @TiO 2 ‐palygorskite nanostructured particles were synthesized separately with original route to ensure the growth of TiO 2 and then of SiO 2 on the surface of the clay. Accordingly, the introduction of the synthetic filler (SiO 2 @TiO 2 ‐paly) into the electrolyte membrane (Nafion) aims to improve mechanical, thermal, and proton conductivity properties. The TiO 2 nanoparticles were generated via a sol–gel process on the external surface of palygorskite. Then, SiO 2 nanoparticles were synthetized using a similar sol–gel process, onto the TiO 2 ‐palygorskite particles to produce the final SiO 2 @TiO 2 ‐palygorskite particles. The physico‐chemical properties of the nanostructured particles were studied by X‐ray diffractometry, Fourier transform infrared, scanning electron microscopy, and transmission electron microscopy. Nafion based composite membranes were prepared using SiO 2 @TiO 2 ‐palygorskite and TiO 2 ‐palygorskite as a control standard. The composite membranes show improved mechanical properties, thermal stability, water retention, and proton conductivity compared to the neat Nafion membrane. Proton conductivities (at 100°C and 100% relative humidity) increased from 65.0 mS/cm for neat Nafion to 70.4 mS/cm and to 128.6 mS/cm when incorporated TiO 2 ‐Paly (6% in weight) and SiO 2 @TiO 2 ‐Paly (6% in weight), respectively.