Au/TiO2 catalysts prepared by borohydride reduction for preferential CO oxidation at near-ambient temperature

Georgia Barbalho Leal,Daniela C Loureiro Da Silva,Reinaldo Giudici,Rodolfo M Antoniassi,Marcelo Linardi,Jorge Moreira Vaz,Estevam V Spinacé,Ligia Ciotti,Beatriz Naomy Watacabe

doi:10.1515/cse-2019-0002

Georgia Barbalho Leal, Daniela C Loureiro Da Silva + Show 7 more

Open Access

https://doi.org/10.1515/cse-2019-0002

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Journal: Catalysis for Sustainable Energy	Publication Date: Jan 1, 2019
Citations: 1	License type: CC BY 4.0

Abstract

Abstract Au nanoparticles were prepared in solution using HAuCl4.3H2O as Au precursor, sodium citrate as stabilizing agent and sodium borohydride as reducing agent. The influence of synthesis parameters such as BH4:Au and Citrate:Au ratios were studied. In a further step, the stabilized Au nanoparticles were supported on TiO2 with different Au loadings (wt%). The resulting Au/TiO2 catalysts were characterized by Energy-dispersive X-ray spectroscopy, X-ray diffraction and Transmission Electron Microscopy and tested for the preferential oxidation of carbon monoxide in hydrogen-rich stream. Au nanoparticles stabilized in solution were obtained with sizes in the range of 3-4 nm. After supported on TiO2, the Au nanoparticles size did not change and the Au/TiO2 catalysts exhibited excellent performance and stability in the temperature range of 20 - 50°C.

Highlights

Au nanoparticles were prepared in solution using HAuCl4.3H2O as Au precursor, sodium citrate as stabilizing agent and sodium borohydride as reducing agent
Au nanoparticles supported on TiO2 (Au/TiO2 catalyst) have been considered as one of the most active catalyst at temperatures lower than 100 oC for CO-PROX reaction and studies have shown that the procedure used to prepare Au/TiO2 catalysts has a significant influence on the catalytic performance as a result of Au nanoparticles size that should be smaller than 5 nm and Au-TiO2 interactions [1, 3]
Stabilized Au nanoparticles were prepared in solution using HAuCl4.3H2O as Au precursor, sodium citrate as stabilizing agent and sodium borohydride as reducing agent

Summary

Introduction

Abstract: Au nanoparticles were prepared in solution using HAuCl4.3H2O as Au precursor, sodium citrate as stabilizing agent and sodium borohydride as reducing agent. Au nanoparticles supported on TiO2 (Au/TiO2 catalyst) have been considered as one of the most active catalyst at temperatures lower than 100 oC for CO-PROX reaction and studies have shown that the procedure used to prepare Au/TiO2 catalysts has a significant influence on the catalytic performance as a result of Au nanoparticles size that should be smaller than 5 nm and Au-TiO2 interactions [1, 3]. We used a simple and easy strategy to prepare Au/TiO2 catalysts where Au nanoparticles were first prepared in solution using citrate as stabilizing agent and sodium borohydride as reducing agent and in a further step the pre-formed Au nanoparticles with sizes in the range of 3-4 nm were supported on TiO2. The histograms were constructed by measuring the diameter of the Au nanoparticles from micrographs

Preparation of stabilized Au nanoparticles solution

Catalytic Tests

Results and Discussion

Conclusions