Insightful understanding of hot-carrier generation and transfer in plasmonic Au@CeO2 core-shell photocatalysts for light-driven hydrogen evolution improvement

Plasmonic metal@semiconductor core-shell nanoparticles (CSNPs) are considered as promising candidates for artificial photosynthesis. Herein, Au@CeO2 CSNPs are hydrothermally fabricated for photocatalytic hydrogen evolution reaction (HER). CSNPs deliver superior HER performance compared to free CeO2. In particular, Au@CeO2-18 model (shell thickness of 18 nm) produces an HER rate of 4.05 mu mol mg(-1) h(-1), which is similar to 10 times higher than that of pure CeO2 (0.40 mu mol mg(-1) h(-1)) under visible-light. Additionally, Au@CeO2-18 photocatalyst demonstrates long-term stability after five repetitive runs, at which point it only loses approximately 5% of the activity, while core-free CeO2 decreases by 37.5 %. Such improvements are attributed to the electronic interactions between Au and CeO2, which not only enriches Ce3+ active sites to narrow bandgap of ceria toward visible, but also increases the affinity for hydrogen ions on the CSNPs surface. Moreover, localized surface plasmon resonance is light-excited and decays to efficiently produce hot-carrier to drive catalytic reactions.