Oxygen Reduction at the Water|Oil|Electrode Interface Drives Tunable Transition Metal Hydroxide Electroprecipitation

reduction reaction is driven, producing immediate pH gradients near the three-phase boundary, which are visualized in real-time via fluorescence microscopy and used to selectively drive transition metal electroprecipitation at the three-phase boundary. This work presents evidence of significant (and useful) pH gradients at three-phase boundaries and has implications across microdroplet reactivity and nanomaterial electrodeposition.