MOF-derived CoO_x/MgO dual modification boosting hematite photoelectrocatalysis

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.