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

[Display omitted] •Plasmonic Au@CeO2 CSNPs are fabricated for visible-light-driven HER activity.•HER rate of Au@CeO2-18 (shell thickness of 18 nm) is ∼10 times higher than that of CeO2.•Au@CeO2-18 delivers long-term HER stability after several repetitive tests over 20 h.•Synergistic effect of Au and CeO2 is discussed based on the excitation and decay of LSPR.•Experiments are supported by theoretical investigations as well. 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 μmol mg–1 h–1, which is ∼10 times higher than that of pure CeO2 (0.40 μmol 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.