Interfacial binding-enhanced charge transport for CoFe-MOF/Fe2O3 photoanodes with excellent PEC performance

The strong interfacial binding between the in situ formed CoFe-MOF cocatalyst and Fe2O3, which facilitates rapid charge carrier transfer on the heterojunction surface. The as-obtained CoFe-MOF/F photoanode exhibits a PEC performance 2.2 times higher than that of the pristine Fe2O3 photoanode. [Display omitted] •Enhanced interfacial binding between CoFe-MOF and Fe2O3 boosts charge transfer efficiency.•High-quality interface contact effectively improves PEC performance.•Co/Fe synergistic effect of bimetallic CoFe-MOF has contributed to the activity. Interfacial charge-transfer efficiency determines the photoelectrochemical (PEC) performance of Fe2O3-based heterojunction photoanodes. Herein, we present Fe2O3 nanoarrays coated by CoFe bimetal organic framework (CoFe-MOF) nanolayers (CoFe-MOF/F) via in-situ solvothermal method. The resulting CoFe-MOF/F photoanode has a current density of 2.2 mA cm−2 at 1.23 V vs. RHE, which is about 2.2 times that of pristine Fe2O3. Moreover, the CoFe-MOF/F photoanode shows a negative shift of onset potential, and excellent long-term PEC stability. The in-situ synthesized CoFe-MOF on the photoanode surface enhances the interaction force between the photoanode and the photoanode and strengthen the interface binding, therefore, the interface defects are reduced and the transfer efficiency of interfacial carriers increases, wich effectively improve the performance of the photoanode. This work provides an in-situ strategy for enhancing the binding force between the cocatalyst and the photoanode to improve the PEC performance of the photoelectrode. This approach is not only effective but also scalable, offering the prospect of optimizing the performance of a wide range of photoanode materials.