Preparation of Au/TiO2 Catalyst by a Liquid-Phase Reduction Method for Preferential Oxidation of Carbon Monoxide in a Hydrogen Rich-Stream (CO-PROX reaction)

Abstract

Au nanoparticles supported on TiO 2 were prepared by a liquid-phase reduction method using HAuCl 4 .3H 2 O as the Au precursor, TiO 2 as the support, a solution of ethylene glycol/water as solvent and reducing agent and sodium citrate as reducing agent and stabilizer. The Au/TiO 2 catalysts were prepared using different routes and characterized by Energy-dispersive X-ray spectroscopy, X-ray diffraction and Transmission Electron Microscopy and tested for preferential oxidation of carbon monoxide in hydrogen-rich stream (CO-PROX reaction). The way that the Au precursor, the TiO 2 support and the sodium citrate is added to the ethylene glycol/water solution strongly influences the Au nanoparticle sizes and the catalytic activity of the obtained materials.

New Strategy for Creating TiO2 Thin Films with Embedded Au Nanoparticles

“…This fact indicates the decisive role of EG in the formation of stable AuCNP ink. We supposed that the particles with a size range from 250 to 400 nm are an agglomerate of TiO 2 NPs, nascent Au clusters, ionic species of HAuCl 4 decomposition, and EG molecules (AuCNP) [25][26][27][32][33][34][35]. The Raman spectra of the N1, N2, and N5 dispersions are presented in Figure 2.…”

“…It was noticed that the plasmon band appeared only after the decay of the absorbance of Au(III) species [26]. In the liquid-phase reduction method, the combination of components and the order of their introduction into the reactor affects the size of Au NPs and, accordingly, the catalytic activity of the obtained materials [27]. Typically, small Au NPs (2-5 nm) have higher activity, and the catalytic performance is sensitive to the preparation method and residual chloride content.…”