E1 and E2: Two host-modified electrodes were first absorbed with guest 3 (E1) or guest 1 (E2) for 16 h. Alcohol oxidation was performed with guest 3 (E1), followed by reabsorption of guest 1 to perform ammonia oxidation, and vice versa for E2, first performing ammonia oxidation with guest 1, followed by reabsorption with guest 3 and alcohol oxidation. ) guest 1 is reabsorbed onto the same electrode E1 (c) CV of 2 nd absorption with guest 1 in aqueous NaClO4 (0.2 M, pH 7, 100 mV s -1 ) and (d) in aqueous NH3 (0.2 M, phosphate buffer at pH 10.8, 20 mV s -1 ) to then perform ammonia oxidation (entry E1, Table ).