Gold nano-particles supported on hematite and magnetite as highly selective catalysts for the hydrogenation of nitro-aromatics
by Fernando Cárdenas-Lizana; Santiago Gómez-Quero; Lioubov Kiwi-Minsker; Mark A. Keane
International Journal of Nanotechnology (IJNT), Vol. 9, No. 1/2, 2012

Abstract: The catalytic action of nano-sized Au particles supported on hematite (Fe₂O₃) and magnetite (Fe₃O₄) is compared in the continuous gas phase hydrogenation of p-chloronitrobenzene and m-dinitrobenzene. The catalysts were prepared by deposition-precipitation and have been characterised in terms of BET/pore volume, powder X-ray diffraction (XRD), temperature programmed reduction (TPR), H₂ chemisorption, high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) measurements. XRD confirmed the formation Fe₂O₃, which was transformed into Fe₃O₄ during TPR to 673 K with a concomitant decrease in BET area and pore volume. Post-TPR to 423 K, Au/Fe₂O₃ exhibited well dispersed pseudo-spherical Au particles with mean diameter = 2.0 nm. HRTEM and XPS demonstrate the encapsulation of Au in the Fe₃O₄ matrix after TPR to 423 K, which inhibited hydrogenation rate. Thermal treatment to 673 K resulted in the segregation of Au on the Fe₃O₄ surface and the formation of nano-scale particles with mean diameter = 4.0 nm. Similar activities were recorded over both Au/Fe₂O₃ and Au/Fe₃O₄ with exclusive nitro-group reduction to yield p-chloroaniline and m-nitroaniline, a response that is discussed in terms of Au electronic character.

Online publication date: Mon, 09-Jan-2012

The full text of this article is only available to individual subscribers or to users at subscribing institutions.

 
Existing subscribers:
Go to Inderscience Online Journals to access the Full Text of this article.

Pay per view:
If you are not a subscriber and you just want to read the full contents of this article, buy online access here.

Complimentary Subscribers, Editors or Members of the Editorial Board of the International Journal of Nanotechnology (IJNT):
Login with your Inderscience username and password:

Username:        Password:          Forgotten your password?

Want to subscribe?
A subscription gives you complete access to all articles in the current issue, as well as to all articles in the previous three years (where applicable). See our Orders page to subscribe.

If you still need assistance, please email subs@inderscience.com