Boosting Photogenerated Electron Extraction by Atomic Termination Engineering of Ferroelectric PbTiO ₃ for Efficient Photocatalytic Overall Water Splitting

Single-domain ferroelectric PbTiO₃ is regarded as a promising candidate for photocatalytic overall water splitting (POWS) owing to its highly efficient bulk charge separation driven by strong polarization field. However, its POWS efficiency still remains far below expectations. Herein, we identify interfacial photogenerated electron extraction at the PbTiO₃-Rh interface as a critical factor determining POWS performance. Systematic studies reveal that thermodynamically favored Pb-O termination severely impedes this process. To overcome this limitation, a facile alkaline-etching strategy is developed to selectively reconstruct surface termination from Pb-O to Ti-O on photogenerated electron-rich facet. Time-resolved photoluminescence spectroscopy and excited-state electron transfer dynamics simulation demonstrate that the resulting Ti-O termination remarkably accelerates interfacial photogenerated electron extraction, leading to a 46.1-fold enhancement in POWS activity. An apparent quantum yield of 6.8% at 360 nm is achieved, representing a record value among reported ferroelectric photocatalysts for POWS. Mechanistic studies reveal that weakened interfacial electric field and enhanced nonadiabatic coupling strength at the Ti-O-Rh interface jointly accelerate photogenerated electron extraction. This work underscores the importance of surface-termination engineering in enhancing interfacial photogenerated electron extraction and provides insight into designing high-performance photocatalysts.