MOF-derived CoOx/MgO dual modification boosting hematite photoelectrocatalysis

Abstract

Metal–organic frameworks (MOFs) enhance photoelectrochemical (PEC) performance primarily through increased surface area, yet suffer from inefficient charge transport and underutilization of catalytically active sites embedded within their frameworks. MOF-derived materials effectively overcome these limitations. In this work, we rationally designed an efficient PEC photoanode by modifying Fe₂O₃ with in situ derived CoO_x from ZIF-67 as a co-catalyst, coupled with an MgO hole-transport interlayer. The resulting CoO_x/MgO/Fe₂O₃ architecture achieved a photocurrent density of 0.50 mA cm⁻² at 1.23 V vs. RHE, representing a 2.5-fold enhancement over pristine Fe₂O₃. Systematic characterization reveals that MgO facilitates hole transfer and improves band bending, while MOF-derived CoO_x provides abundant active sites. The architecture has significantly improved charge injection efficiency and separation efficiency.