LSPR-driven upconversion enhancement and photocatalytic H2 evolution for Er-Yb:TiO2/MoO3-x nano-semiconductor heterostructure

Localized surface plasmon resonances (LSPR) are widely employed for improving the upconversion luminescence (UCL) and photocatalysis. Here, we prepare a nano-semiconductor heterostructure (NSH) consisting of Er-Yb:TiO2 nanosheets (NTs) integrated with plasmonic MoO3-x NTs in a two-step solvothermal processes. The LSPR of MoO3-x amplifies and transfers the near-infrared (NIR) energy to the neighboring Er-Yb:TiO2 UC system, leading to a 182-fold increase in green emissions. Moreover, the LSPR effect extends the absorption range of the Er-Yb:TiO2/MoO3-x NSH from the visible to the NIR region. The interface of the Er-Yb:TiO2/MoO3-x NSH acts as a charge carrier channel to separate the plasmon-induced electrons and holes effectively. We perform H-2 production experiments of Er-Yb:TiO2/MoO3-x NSH from ammonia borane (BH3NH3). Upon the excitation of a 980 nm laser, the H-2 production of the Er-Yb:TiO2/MoO3-x NSH is 1.5 times and 61 times higher than that of the MoO3, NTs and BH3NH3. In addition, the H-2 yield is 2.5 times and 52 times higher than that of the MoO3. x NTs and BH3NH3 under the irradiation of simulated sunlight (AM 1.5), demonstrating the superior photocatalytic properties of the Er-Yb:TiO2/MoO3-x NSH.