A　sandwich-structured　NaYF4:Yb3+,　Er3+/Au/CdS　architecture,　as　an　up-conversion-involved　photocatalyst　for　H2　production　through　photoreforming　of　renewable　bio-ethanol,　was　constructed　successfully.　The　Au　nanoparticles　embedded　in　the　NaYF4:Yb3+,　Er3+/CdS　interface　play　a　quadruplex　role　to　improve　the　solar　utilization　efficiency.　First,　plasmonic　Au　works　as　a　light　nanoantenna　to　harvest　more　incident　light.　Second,　plasmonic　Au　acts　as　an　energy　relay,　in　which　Au　SPR-induced　Förster　resonance　energy　transfer　(FRET)　and　plasmonic　resonance　energy　transfer　(PRET)　synergistically　facilitate　the　energy　transfer　from　NaYF4:Yb3+,　Er3+　to　Au　to　CdS.　Third,　Au　acts　as　an　electron　sink　to　promote　electron-hole　separation.　Lastly,　Au　serves　as　a　co-catalyst　to　activate　H2　evolution　from　bio-ethanol.　The　multifunctional　Au　makes　NaYF4:Yb3+,　Er3+/Au/CdS　exhibit　enhanced　NIR-driven　photocatalytic　bio-ethanol　reforming　activity.　Moreover,　NaYF4:Yb3+,　Er3+/Au/CdS　shows　superior　photoactivity　under　simulated　sunlight.　This　unique　fabrication　has　implications　for　the　rational　design　of　highly　efficient　solar-energy-harvesting　devices.　©　2017　The　Royal　Society　of　Chemistry.