Laser Preparation of Bimetallic Au–Pt Nanoparticles for Modification of Dark TiO2 Photocatalyst

Bimetallic Au–Pt nanoparticles with different molar ratios were obtained using laser synthesis (Nd:YAG laser with the parameters: 1064 nm, 180 mJ, 7 ns, and 20 Hz). The bimetallic nature of the particles was confirmed by X-ray diffraction and UV-visible spectroscopy. According to the transmission electron microscopy data, it was found that the bimetallic nanoparticles were represented by the alloy particles of an elongated shape with a diameter of 5–10 nm. Then, the bimetallic particles were decorated with a powder of highly defective dark titania by impregnation.The photocatalytic activity of the TiO2 with deposited bimetallic particles was estimated in the reactions of Rhodamine B dye decomposition and hydrogen production under LED irradiation with a wavelength of 375 nm. It was found that the highest photocatalytic activity in the series was exhibited by the samples with the deposited bimetallic particles, where the Au : Pt ratios was 50 : 50 and 30 : 70. It was also shown that the TiO2 nanoparticles decorated with the bimetallic Au : Pt NPs exhibited higher activity compared to the samples successively modified with monometals in the same ratios.