Boosting solar hydrogen production with polarized MOF-derived ferroelectric In2Se3/In2O3 nanohybrids

Abstract

Solar-driven photoelectrochemical (PEC) water splitting is widely considered a promising technology for sustainable hydrogen generation. However, two major challenges hinder its broad use: efficient separation of photogenerated charges and long-term stability. Here we fabricated a ferroelectric-semiconducting In₂Se₃/In₂O₃ nanocomposite by using a metal–organic framework (MOF) template method. After negatively poling (−3 V) the 20%-In₂Se₃/In₂O₃ photoanode, the optimized PEC devices showed a maximum current density of 1.91 mA cm⁻² (at 1.6 V vs. RHE) under one-sun illumination (AM 1.5G, 100 mW cm⁻²), a ∼1.7 and 2.4-fold increase over the reference device based on only In₂Se₃ (0.7 mA cm⁻²) and In₂O₃ (0.56 mA cm⁻²) photoanodes. The enhanced performance is attributed to a Type II (staggered) band alignment heterostructure formed by the In₂Se₃/In₂O₃, which creates a favourable band energy alignment for the separation of the photogenerated charges. A systematic investigation of UV-visible absorption and band alignment reveals that the increased photocurrent density arises from improved charge separation induced by ferroelectric depolarization. Our findings validate the use of MOF-templated In₂Se₃/In₂O₃ composite that combines ferroelectric and semiconducting properties. This approach is promising for improving the performance of hydrogen-generating PEC systems.