Photoactivity Enhancement of WO3 Photoanodes Using the Combined Effect of Plasmonic Au and Photoluminescent Y2O3:Eu3+ Nanoparticles

The WO3 photoanode has great potential application for solar photoelectrochemical water oxidation due to suitable band edge positions with water oxidation potentials. However, it suffers from poor light absorbance in the visible region. Here, we use Eu3+-doped Y2O3 nanoparticles (NPs) in combination with plasmonic gold (Au) NPs to better utilize and adsorb photons from UV and visible regions of sunlight. We attached plasmonic Au NPs on WO3 to enhance the photocatalytic properties due to the plasmon resonance mechanism. Additional deposition of Y2O3:Eu3+ NPs on Au NPs/WO3 improved the photoactivity of the photoanode further. Y2O3:Eu3+ NPs’ downconversion property, along with their light-scattering effect, converts ultraviolet-region photons into visible-region photons and enforces the plasmon resonance mechanism of Au NPs. Experimental results show the increase of absorbance, improvement of electron–hole separation, and enhancement in photocurrent generation of the resultant photoelectrode.