Activating C-H Bonds by Tuning Fe Sites and an Interfacial Effect for Enhanced Methanol Oxidation.

The interaction mechanism between the reacting species and the active site of α-Fe O -based photoanodes in photoelectrochemical methanol conversion reaction is still ambiguous. Herein, a simple two-step strategy is demonstrated to fabricate a porous α-Fe O /CoFe O heterojunction for the methanol conversion reaction. The influence of the electronic structure of active site and interfacial effect on the reaction are investigated by constructing two different FeO octahedral configurations and heterogeneous structures. The optimal sample ZnFeCo-2 affords high photocurrent density of 1.17 mA cm at 0.5 V vs Ag/AgCl, which is 3.2 times than that of ZnFe (0.37 mA cm ). Meanwhile, the ZnFeCo-2 also exhibits 97.8% Faraday efficiency of CH OH to HCHO, and long-term stability over 40 h. Furthermore, density functional theory calculations reveal that the heterostructured α-Fe O /CoFe O with favorable electron transfer effectively lowers methanol adsorption, C-H bond activation, and HCHO desorption energy relative to the pristine α-Fe O , resulting in excellent methanol conversion efficiency.