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.

Dual Cocatalysts in TiO2 Photocatalysis

“…Bimetallic cocatalysts can be supplements for each other for achieving better photocatalytic activities. Common explored bimetallic cocatalysts consist of Au–Pt, Au–Pd, Au–Cu, Au–Ag, Pt–Pd, Pt–Cu, etc …”

“…Owing to the fact that the interface is the location where the charge carriers separate, transfer and recombine, controlling the interfacial structures to regulate the type and number of contact interfaces is imperative to improve the efficiency of charge transfer and separation. Accordingly, the integration structure of cocatalysts can be classified into three major types: random deposition, facet‐dependent selective deposition and core–shell structure ( Figure ).…”

Morphology-Governed Performance of Plasmonic Photocatalysts

“…Besides mono-metallic plasmonic photocatalysts, multi-metallic plasmonic photocatalysts have also been investigated, including bi-(many examples [60,83,[95][96][97]) and tri- [98] metal-modified semiconductors. It has been suggested that preparation of multi-metallic plasmonic photocatalysts should result in enhanced activity because of efficient light harvesting, as the position of LSPR band depends on the kind of noble metal.…”

“…Accordingly, various strategies for charge carriers' separation have been proposed, as already discussed in this review. In the case of efficient light harvesting, the preparation of highly polydisperse NPs of noble metals (broad LSPR [38,56]) and co-modifications with other metals [98], metal oxides [96,122] and metal complexes [105][106][107] have been investigated. Recently, another strategy has been proposed, i.e., using semiconductors in the form of photonic crystals with photonic bandgap and slow photon effect.…”

The Effect of AgInS2, SnS, CuS2, Bi2S3 Quantum Dots on the Surface Properties and Photocatalytic Activity of QDs-Sensitized TiO2 Composite

“…The photocatalytic activity was determined in the toluene degradation process [70]. As an irradiation source, an array of 25 LEDs (λ max = 375 nm, 13.16 mW/cm 2 ) and (λ max = 415 nm, 1.6 mW/cm 2 ) (Optel, Opole, Poland), these diodes contain a part of UV radiation) were used.…”