AuCu/TiO2 catalysts prepared using electron beam irradiation for the preferential oxidation of carbono monoxide in hydrogen-rich mixtures

The major part of the world production of hydrogen (H 2 ) is originated from a combination of methane steam reforming and water-gas shift reaction resulting in an H 2 -rich mixture known as reformate gas, which contains about 1% vol (10,000 ppm) of carbon monoxide (CO). The preferential oxidation reaction of CO in H 2 -rich mixtures (CO-PROX) has been considered a very promising process for H 2 purification, reducing CO for values below 50 ppm allowing its use in PEMFC Fuel Cells. Au nanoparticles supported on TiO 2 (Au/TiO 2 ) catalysts have been shown good activity and selectivity for CO-PROX reaction in the temperature range between 20-80 oC; however, the catalytic activity strongly depends on the preparation method. Also, the addition of Cu to the Au/TiO 2 catalyst could increase the activity and selectivity for CO-PROX reaction. In this work, AuCu/TiO 2 catalysts with composition 0.5%Au0.5%Cu/TiO 2 were prepared in a single step using electron beam irradiation, where the Au 3+ and Cu 2+ ions were dissolved in water/2-propanol solution, the TiO 2 support was dispersed and the obtained mixture was irradiated under stirring at room temperature using different dose rates (8 – 64 kGy s -1 ) and total doses (144 – 576 kGy). The catalysts were characterized by energy dispersive X-ray analysis, X-ray diffraction transmission electron microscopy, temperature-programmed reduction and tested for CO-PROX reaction.  The best result was obtained with a catalyst prepared with a dose rate of 64 kGy s -1 and a total dose of 576 kGy showed a CO conversion of 45% and a CO 2 selectivity of 30% at 150 o C.