The formation of the HG complex could be confirmed by CV (Figure ) and UV/Vis spectroscopy (Figure ) and is also visible to the naked eye in the form of electrode surface staining after HG formation. The observation of the redox peaks of the guests indicates that electron transfer between the catalysts and the electrode surface is possible. The redox couples of guest 1 are observable at around -0.09 V vs. Fc/Fc + for the Ru (II/III) oxidation (Figure red), whereas guest 2 shows its related redox peak at more positive potentials (Figure blue), which is likely due to a ligand exchange. In 0.5 M ammonia solution (THF) (Figure ), an onset for ammonia oxidation with both guests can be observed at around -0.22 V vs Fc/Fc + in comparison to the blank without a guest (mITO + host, Figure , black dashed line), which shows a slightly earlier onset and higher current for guest 1 (red). The difference in current is attributed to catalyst loading. Guest 1 exhibits a higher amount of immobilized catalyst (0.026 mC), which can be determined from the integration of the redox peaks (Figure ) and which corresponds to a catalyst loading of 1.14 pmol cm in comparison to guest 2, exhibiting 0.015 mC and a surface loading of 0.66 pmol cm -2 . The higher surface loading of guest 1 could be due to its slightly smaller size, which enables the catalyst to better infiltrate the mesoporous structure of the electrode. Chronoamperometry (CA) was employed to gain information on the stability of the HG-immobilized assembly during electrocatalysis. The applied potential was set to 0.1 V vs Fc/Fc + in THF, which is slightly more oxidative than the Ru(II)/Ru(III) oxidation peak of guest 2. After 90 min of operation (in 0.5 M NH3 in THF) (Figure ), the electrode functionalized with guest 1 (red) retained more current over time compared to a guest 2-functionalized electrode (blue). This indicates a more robust connection between the adamantyl-substituted guest and the surfacebound hosts, which correlates with the stronger binding observed in solution. Additionally, higher currents were observable for guest 1, which can be explained by the higher surface loading. When comparing CV and CA of the electrodes with physisorbed guest 1 (Figure ), which lacks the host functionalization, no redox peak or catalytic activity was observed, which indirectly confirms the formation of the HG complex in the presence of a host-functionalized surface. After extensive efforts to detect the evolved N2 with gas chromatography (GC) we were unable to unambiguously confirm that N2 was produced from the catalysis due to an unavoidable air leak that was large in comparison to the theoretically produced N2, as the catalyst is in the range of picomolar per cm 2 .