Ag-Decorated ATaO₃ (A = K, Na) Nanocube Plasmonic Photocatalysts with Enhanced Photocatalytic Water-Splitting Properties

Tantalate semiconductor nanocrystals have been at the forefront of the photocatalytic conversion of solar energy to supply hydrogen owing to their favorable and tunable optical and electronic properties as well as advances in their synthesis. However, a narrow band gap is required for response to improve the efficiency of the photocatalysts. Here we propose an efficient enhancement of the H₂ generation under simulated sunlight and visible light irradiation by a dispersion of Ag-decorated KTaO₃ and NaTaO₃ nanocubes. X-ray diffraction and UV–vis diffuse reflectance spectra are used to characterize the products. Transmission electron microscope (TEM) and high-resolution high-angle annular dark-field scanning TEM (HAADF-STEM) images show that the Ag nanoparticles (NPs) are uniformly loaded on the surfaces of KTaO₃ and NaTaO₃. The photocatalytic water-splitting results over Ag-decorated KTaO₃ and NaTaO₃ show that the rate for H₂ evolution from aqueous CH₃OH solutions is up to 185.60 and 3.54 μmol/h·g under simulated sunlight and the rate for H₂ evolution is more than 2 times than that of pure NaTaO₃ and KTaO₃ materials. However, under purely visible light illumination the highest H₂ evolution of 25.94 and 0.83 μmol/h·g is observed in the case of Ag-decorated KTaO₃ and NaTaO₃ nanocubes. To the best of our knowledge, this is the first time that the photocatalytic water-splitting activity of the prepared Ag-decorated KTaO₃ and NaTaO₃ nanocubes has been reported