TiO₂ and NaTaO₃ Decorated by Trimetallic Au/Pd/Pt Core–Shell Nanoparticles as Efficient Photocatalysts: Experimental and Computational Studies

Abstract

Novel triple-layered trimetallic Au/Pd/Pt nanoparticles (NPs) with a porous Pt shell, showing a hedgehog-like structure, were successfully bounded with TiO2 and NaTaO3 surfaces, and used for photocatalytic purpose. To characterize all as-prepared samples, XRD, TEM, EDX, SEM, ISP-OES, DRS, XPS, and photoluminescence (PL) emission spectroscopy were applied. It was found that 25 nm Au/Pd/Pt core–shell NPs were formed, and good interaction between the porous Pt outer shells and the semiconductor surface was obtained. To appraise the effect of the semiconductor’s matrix type and the amount of used AuPdPt NPs on the photocatalytic performance, three types of reactions were employed: (i) degradation of phenol (under mono- and polychromatic irradiation), (ii) the efficiency of toluene removal in gas phase under visible light, and (iii) yield of H2 generation under UV–vis irradiation. Our results proved that the decoration of both TiO2 and NaTaO3 by AuPdPt NPs caused not only an increase in degradation yield of contaminants in the aqueous and gas phases but also significant enhancement in hydrogen generation. Amount of formed hydrogen was raised from 2.19 to 213.8 μmol/min for pristine rutile and rutile decorated by trimetallic NPs, respectively. In addition, the adsorption energy of water and oxygen molecules on modified TiO2_rutile and TiO2_anatase surface were investigated by the density functional (DFT) calculations. Data obtained by theoretical computation was found to be complementary to experimental results. In summary, the ternary metallic core–shell Au/Pd/Pt nanoparticles were successfully applied for TiO2 and NaTaO3 modification and resulted in providing new promising materials for the environmental purification and for production of alternative energy sources when irradiated under visible and UV–vis light.