Size-Dependent Plasmon-Enhanced Photoelectrochemical Performance of Au@Wo3 Nanosheets for Solar Water Splitting

Abstract

Au@WO3 nanosheets with tailored Au nanoparticle sizes were synthesized to explore their plasmon-mediated PEC behavior. Depositing Au nanoparticles on WO3 nanosheets effectively utilize the SPR effect of Au nanoparticles, which significantly expanded the light absorption range and enhanced photogenerated carrier separation. Experimental results showed that the Au@WO3 nanosheets with 8 nm Au nanoparticles demonstrated the best PEC performance, reaching a photocurrent density of 0.78 mA/cm2 at 1.23 V vs. RHE, which is 1.9 times higher than that of pristine WO3 nanosheets. Structural characterization (XPS, SEM) confirmed the uniform distribution of Au nanoparticles on the WO3 nanosheets, with their size and distribution controlled by adjusting the ratio of Au precursor to WO3. EIS results indicated that Au nanoparticles acted as efficient electron collectors, promoting the separation and transport of photo-generated carriers and thereby greatly improving PEC performance. This study offers new insights into the surface modification of plasmon photoanodes and a theoretical basis for optimizing the application of noble metal nanoparticles in PEC water splitting.

Keywords: Plasmon resonance, Tungsten trioxide, Au nanoparticle, Heterojunction, Photocurrent Density