Unraveling the Phase‐Transfer Catalysis Mechanism of Oxygen Reduction Catalyzed by Iron(III) meso‐tetra‐(4‐N‐Methyl‐pyridyl) Porphine at the Liquid/Liquid Interface

Abstract

AbstractWe report an investigation of the oxygen reduction reaction (ORR) catalyzed by FeIII meso‐tetra‐(4‐N‐methyl‐pyridyl) porphine (FeIIITMPyP) at the polarized water/1,2‐dichloroethane (DCE) interface. FeIIITMPyP is a water soluble pentavalent cation, which has a standard Galvani transfer potential of +0.19 V at the water/DCE interface. By four‐electrode cyclic voltammetry and shake‐flask biphasic reactions controlled by chemical polarization at the macroscale water/DCE interface, we demonstrated that FeIIITMPyP can catalyze the reduction of O2 by electron donors (e.g., ferrocene and 1,1′‐dimethylferrocene). Further, based on voltammetry at the free‐standing silica nanochannel membrane (SNM) supported nano‐ITIES (interface between two immiscible electrolyte solutions) array where the transfer of FeIIITMPyP is physically blocked owing to the size‐exclusion effect, we proved that the overall reaction proceeds through a phase‐transfer catalysis (PTC) process, namely the heterogeneous ion transfer of FeIIITMPyP from water to DCE followed by the homogeneous catalyzed ORR in DCE.