Enhanced core-shell CeO2:Er,Yb@W18O49 heterojunction H2 generation by multiband emissions of Er ions

The core-shell CeO2:Er,Yb@W18O49 heterojunction is successfully synthesized via the facile solvothermal method. The octahedral CeO2:Er,Yb nanocrystal's core exhibits green (H-2(11/2), S-4(3/2) -> I-4(15/2)), red (F-4(9/2) -> I-4(15/2)) and NIR (I-4(11/2) -> I-4(15/2) and I-4(13/2) -> I-4(15/2)) emission under 980 nm laser diode excitation, and the multiband emissions are absorbed by the W18O49 nanowire's shell, re-exciting its higher energy localized surface plasmon resonances (LSPR). With the excitation of 980 nm, the photocatalytic property of CeO2:Er,Yb@W18O49 for hydrogen (H-2) evolution from ammonia borane (BH3NH3), a three-fold increase compared to W18O49, is researched. The application of natural sunlight for the production of H-2 is studied, and an obvious H-2 production enhancement compared to the use of W18O49 (two-fold) is also observed. This remarkable enhancement in the catalytic activity of CeO2:Er,Yb@W18O49 heterostructures is ascribed to the re-excitation of LSPR by multiband emissions of CeO2:Er,Yb.