All simulations have been performed by means of the Gaussian and plane waves method as implemented in the CP2K program package. The structures, simulated by density functional theory (DFT), consist of an oxide slab of six layers of rutile TiO2 (110) to which the bisphosphonated cyclodextrin macrocycle has been adsorbed on one side. On both sides, the free oxide surface has been covered by a ~5 Å thick film of liquid water, while the guest complex has been introduced into the empty host cavity. The whole system was first equilibrated at room temperature by ab initio molecular dynamic (AIMD) simulations for a few picoseconds. Then the structure was optimized starting from one AIMD snapshot. Energetics and electronic properties were finally evaluated at the hybrid functional level of theory (Figure ). The optimization of both guests 1 and 2 showed that guest 1 binds slightly stronger to the surface-bound host (-6.97 eV vs. -6.67 eV) (Figure ). Both guest molecules interact with the host, but no hybridization with the substrate orbitals is observed, in contrast to our previous report on gold. To study whether the binding group influences the catalytic performance and stability, guests 1 and 2 were compared during electrocatalysis. To this end, electrodes functionalized with the HG-bound molecular catalysts were prepared. β-CD was functionalized and bound to a mesoporous indium tin oxide (mITO) electrode surface (Figure ) as reported previously. The modified bisphosphonated cyclodextrin macrocycle can bind to the mITO substrate with up to 28 bonds, forming a stable surface-anchored host cavity. For electrocatalysis, the mITO electrode was modified with the host and afterwards dipped for 1 h in a solution of 0.1 mM of each of the guest complexes 1 and 2 in MeOH to form the HG complex (Figure ). The functionalized electrodes were analyzed by cyclic voltammetry (CV) (Figure ) in THF or aqueous solution (set up Figure ) with and without ammonia to assess general electrochemical and catalytic properties for the oxidation of ammonia.