Synthesis and characterization of composite membranes modified with Halloysite nanotubes and phosphotungstic acid for electrochemical hydrogen pumps

One of the main problems in electrochemical hydrogen pumps is the transport of protons, water retention and hydrogen crossover through the membrane. Considering prospects for an electrochemical hydrogen compression system, in this work, membranes based on Sulfonated Poly (Ether-Ether Ketone) (SPEEK) were made and modified with Halloysite nanotubes (HNT) and Halloysite nanotubes impreg- nated with phosphotungstic acid (PWA/HNT30)15. These modified membranes were physicochemically characterized by scanning electron microscopy (SEM), X-Ray diffraction (XRD), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). It was found that the nanotubes were suc- cessfully incorporated by impregnating the heteropolyacid on the nanotubes. In addition, the membranes were characterized by swelling (area and volume) and WUp, obtaining a slight decrease in these values. In contrast, the proton conductivity was increased by 42% and 88% for the membranes impregnated with HNTs and (PWA/HNT30)15, respectively. Finally, the membranes were evaluated in a hydrogen pumping system, and lower energy consumption at j = 0.4 A cm-2 has been obtained.