BLD BLD BLD Surface area / cm 3. The first absorption shows a broad average peak, attributed to the overlapping of the Ru II /Ru III and the Ru III /Ru IV oxidations. After 90 min of electrocatalysis in 0.2 M NH3 phosphate buffered solution at pH 10.8, reabsorption of the guest molecule is still possible, even though the surface loading is reduced to only 30% of its initial coverage, resulting in lower currents during the second electrocatalysis (red). We assume that PA [6] is lost during the first catalysis cycles, showing lower catalyst loading. Afterwards, the host on the surface remains stable since the third absorption (blue) is very similar to the second one (red). At this low current, product formation was below the detection limit of the Griess test. Guest, pH and medium exchange PA [6]-modified electrodes can be reused for different catalytic reactions, including the exchange of guest molecules. To demonstrate that the PA6-modified electrodes are reusable for different reactions and at different pH after electrocatalysis and reabsorption with fresh guest, four electrodes (E1-E4) were prepared: Two electrodes (E1 and E2) were used to exchange the guest molecules to perform different reactions at different pH.