Dual Surface Modification with LDH and MOF for Improving Carrier Transport of Hematite Photoanode

ABSTRACT The construction of heterojunction onto hematite (α‐Fe 2 O 3 ) photoanode can effectively relieve its inherent defects such as serious charge recombination and short distance of carrier transfer. The introduction of layered double hydroxide (LDH) and metal‐organic framework (MOF) as surface cocatalysts may generate an effective built‐in electric field at the interface between α‐Fe 2 O 3 photoanode and LDH/MOF cocatalyst. This can directly accelerate photogenerated electrons and holes transport. In this work, the Fe–Ni LDH and Fe–Ni MOF are first simultaneously loaded onto α‐Fe 2 O 3 photoanode by hydrothermal method. The α‐Fe 2 O 3 /LDH/MOF photoanode exhibits the optimal photocurrent density of 2.03 mA/cm2 at 1.23 V vs. RHE, a 140% enhancement compared with that of bare α‐Fe 2 O 3 photoanode. The internal LDH nanosheets can enrich the surface‐active sites, improve the electric conductivity, and reduce charge recombination. The outmost MOF overlayer effectively alleviates the structural collapse and the loss of active components, enhancing the reaction stability of α‐Fe 2 O 3 /LDH/MOF photoanode. Furthermore, the interfacial heterojunction formed between α‐Fe 2 O 3 photoanode and LDH/MOF cocatalyst can synergistically promote photogenerated carrier separation and transfer, and effectively enhance the PEC catalytic performance of α‐Fe 2 O 3 photoanode.