Au nanoparticles loaded Ta2O5@nanohoneycomb structure for visible-light-driven photocatalytic hydrogen evolution

On the basis of localized surface plasmon resonance (LSPR) effect, UV light-sensitive photocatalysts may absorb visible light with the loading of metallic plasmonic nanoparticles. In this work, a nanohoneycomb (nHC) structure with the average cell size of 79 nm was fabricated by a galvanic replacement reaction of Al with Ni. A 3.7 nm-thick Ta2O5 thin film was then coated on the nHC by atomic layer deposition. Au nanoparticles were subsequently deposited on the Ta2O5 film to function the LSPR effect. The LSPR phenomenon was observed by examining the UV-Vis absorption spectra, and the intensity was found to be correlated to the size of Au nanoparticles which could be adjusted by the annealing temperature. Simulation of the scattering spectra of four samples based on the Mie theory was conducted to explain the LSPR effect. The photocatalytic activities of hydrogen evolution from water splitting for the samples with Pt cocatalyst were evaluated under visible light irradiation. The results revealed that they successfully generated hydrogen, and the highest evolution rate was achieved by the sample annealed at 650 degrees C, which was 71 % higher than that of the as-prepared sample. A mechanism is proposed to explain the hydrogen evolution behavior.