Nanocomposite Based on Functionalized Gold Nanoparticles and Sulfonated Poly(ether ether ketone) Membranes: Synthesis and Characterization

Gold nanoparticles, capped by 3-mercapto propane sulfonate (Au-3MPS), were synthesized inside a swollen sulfonated poly(ether ether ketone) membrane (sPEEK). The formation of the Au-3MPS nanoparticles in the swollen sPEEK membrane was observed by spectroscopic and microscopic techniques. The nanocomposite containing the gold nanoparticles grown in the sPEEK membrane, showed the plasmon resonance λmax at about 520 nm, which remained stable over a testing period of three months. The size distribution of the nanoparticles was assessed, and the sPEEK membrane roughness, both before and after the synthesis of nanoparticles, was studied by AFM. The XPS measurements confirm Au-3MPS formation in the sPEEK membrane. Moreover, AFM experiments recorded in fluid allowed the production of images of the Au-3MPS@sPEEK composite in water at different pH levels, achieving a better understanding of the membrane behavior in a water environment; the dynamic hydration process of the Au-3MPS@sPEEK membrane was investigated. These preliminary results suggest that the newly developed nanocomposite membranes could be promising materials for fuel cell applications

Sol-gel route: An original strategy to chemically stabilize proton exchange membranes for fuel cell

International audienceWe present the elaboration, via a Sol-Gel (SG) route, of a new generation of hybrid membranes for PEMFC applications, in order to improve their performances and durability. The strategy was to create, within a commercial sPEEK membrane, a reactive SG phase able to reduce the oxidative species generated during FC operation and to improve the proton conductivity. The SG content is adjusted by tuning the SG precursors/sPEEK ratio used for the impregnation step. Raman analyses show that a uniform distribution of the SG phase in the membrane section is obtained when NMR analyses demonstrate its high extent of condensation, and reveal the structuring effect of the sPEEK membrane on the SG phase at the nanoscale. The membranes exhibit a better liquid water uptake and proton conductivity than pristine sPEEK membrane up to a SG uptake of 18%, with a gas permeability slightly higher than sPEEK but still lower than the benchmark Nafion. H2O2 accelerated aging tests evidenced the ability of the SG phase to prevent the oxidative degradation of sPEEK. Finally, the FC operability tests showed better and more durable performances for the hybrid membranes, without any increase of the gas permeability during operation