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)

Julian M De Souza Pereira,Jorge Moreira Vaz,Ligia Ciotti,Estevam Vitorio Spinacé

doi:10.1590/1980-5373-mr-2017-0756

Julian M De Souza Pereira, Jorge Moreira Vaz + Show 2 more

Open Access

https://doi.org/10.1590/1980-5373-mr-2017-0756

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Journal: Materials Research	Publication Date: Dec 18, 2017
Citations: 4	License type: cc-by

Abstract

Au nanoparticles supported on TiO2 were prepared by a liquid-phase reduction method using HAuCl4.3H2O as the Au precursor, TiO2 as the support, a solution of ethylene glycol/water as solvent and reducing agent and sodium citrate as reducing agent and stabilizer. The Au/TiO2 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 TiO2 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.

Highlights

The chemical industry produces millions of tons of hydrogen in the world through the steam reforming process of hydrocarbons and the water-gas shift reaction resulting in a hydrogen-rich gas mixture containing 15-20% of CO2, 10% of H2O and about 1% vol (10.000 ppm) of carbon monoxide (CO)
The EDX analysis of Au/TiO2 catalysts obtained by routes A-D (Table 1) showed for all samples that the contents of
Au/TiO2 (A) and (B) catalysts presented low activities and selectivities for CO-PROX reaction when compared to the results described in the literature[6,7,8,9,10,14,18], which may be related to the size of the Au nanoparticles present in these catalyst (> 20 nm)

Summary

Introduction

The chemical industry produces millions of tons of hydrogen in the world through the steam reforming process of hydrocarbons (methane, coal) and the water-gas shift reaction resulting in a hydrogen-rich gas mixture (reformate gas) containing 15-20% of CO2, 10% of H2O and about 1% vol (10.000 ppm) of carbon monoxide (CO) Most of this hydrogen produced in the world is used in the manufacture of ammonia for use in fertilizers[1] and lately, there is a great interest in the use of hydrogen in low temperature fuel cells[2]. We studied the preparation of Pt nanoparticles supported on carbon (Pt/C electrocatalysts for fuel cells) by a liquid-phase reduction method, called alcohol-reduction process, using ethylene glycol as reducing agent[11,12]. We prepared Au/TiO2 catalysts by a liquidphase reduction method using HAuCl4.3H2O as the Au precursor, TiO2 as the support, a solution of ethylene glycol/ water as solvent and reducing agent and sodium citrate as reducing agent and stabilizer

Experimental

Catalytic tests

Results and Discussion

Conclusions