Electroanalytical Probing of Triphasic Hydrogen Storage and Transport in Films of Nanoparticulate Polymer of Intrinsic Microporosity (PIM-1)

Preliminary experiments are reported to show quantitatively that hydrogen gas can be stored under triphasic conditions in wet nanoparticulate polymer of intrinsic microporosity (PIM-1) applied as a film to a platinum disk electrode surface. Based on chronoamperometric data, it is shown that the resulting triphasic interface is able to store hydrogen gas at apparent concentrations higher (3 orders of magnitude increase for an approx. 15 μm thick film with typically c _app,hydrogen = 80 mM; D _app,hydrogen = 1.2 × 10 ^–11 m ²s ⁻¹) than the known solubility of hydrogen gas in aqueous electrolyte (c _hydrogen = 0.08 mM; D _hydrogen = 5.0 × 10 ^–9 m ²s ⁻¹) at room temperature. Due to film roughness/heterogeneity, the apparent hydrogen concentration can only be estimated, but it increases with film thickness. At the same time the apparent diffusion coefficient is lowered considerably due to the molecularly rigid/glassy polymer host. The resulting modified electrode is investigated/proposed for energy storage applications with different amounts of PIM-1 nanoparticle deposits attached to the platinum surface.