How changes in tunable alkyl aryl ionic liquids impact the synthesis of platinum nanoparticles to catalyze the hydrogen evolution reaction

This study compares different tunable alkyl aryl ionic liquids (TAAILs) with NTf2 as anion for their usage as solvent in nanoparticle (NP) synthesis. TAAILs are ionic liquids (ILs) with a 1-aryl-3-alkylimidazolium cation. Changes in both alkyl chain length and aryl substitution pattern are investigated for the synthesis of platinum nanoparticles (Pt-NPs) with respect to the NP’s size and catalytic activity. The NPs were supported in situ on the commercially available carbon material Vulcan to prevent aggregation and increase the electric conductivity. Transmission electron microscopy (TEM) images revealed the successful synthesis of NPs with a size of 2–9 nm and very low agglomeration in a microwave reaction after only 10 min at 200 °C. To determine the catalytic activity of Pt-NPs, the electrocatalytic hydrogen evolution (HER) was selected. The obtained Pt-NP/Vulcan composites reached overpotentials as low as 19 mV with a mass activity of up to 1980 A g-1.