Mie resonance in hollow nanoshells of ternary TiO₂-Au-CdS and enhanced photocatalytic hydrogen evolution

We design a ternary TiO₂-Au-CdS photocatalyst with controllable Mie scattering peak for the first time to verify if matching the Mie scattering peak with the absorption peak of semiconductors could greatly improve their photocatalytic performances. By varying the inner diameter of TiO₂ nanoshell from 150 to 255 nm, the Mie scattering peak was controlled from below 370–510 nm. When the Mie scattering peak of TiO₂ nanoshell (inner diameter = 185 nm) matches the absorption band of CdS, a highest visible-light photocatalytic hydrogen production rate (669.7 μmol h⁻¹ g⁻¹) was observed among all the ternary photocatalysts with different inner diameters. The backscattering calculation based on Mie's theory and the comparison of photocatalytic performances of different composite catalysts including TiO₂, TiO₂-Au, and TiO₂-CdS hollow nanoshells also confirmed that the scattering phenomenon in hollow nanoshells is beneficial for photocatalysis. This work may favor various technological applications of Mie scattering for effective light utilization.