Abstract

PICASSO, Gino et al. Nanosized catalysts based on Fe oxide for combustion of n-hexane. Rev. Soc. Quím. Perú [online]. 2009, vol.75, n.2, pp.163-176. ISSN 1810-634X.

In this work, nanosized catalysts based on Fe oxide have been prepared for total combustion of n-hexane (2000 ppmV). The synthesis ofFe oxide particles have been performed following sol-gel procedure starting from precursors based on nitrate salts. According to XRD analysis, nanopartic1es formed -hematite and the average partic1e size estimated by TEM was 9 nm with formation of agglomerations of 140 nm. Moreover, different c1ays pillared with Al (Al-PILC), Ti (Ti-PILC) and Fe (Fe-PILC) have been synthesized. Some samples based on Fe-Mn equimolar mixed oxide supported on Al-PILC (FeMn/ A1-PILC) and on Ti-PILC (FeMn/Ti-PILC) have been prepared in order to study the cooperative effect of Mn. Experimental conditions of calcination were adjusted in order to obtain samples with high thermal stability. XRD analysis ofpillared samples revealed the formation of stable pillars, except for Fe-PILC which described a delaminated structure. As a consequence of pillaring, an enhancement of total surface area compared to starting clay material is observed. Concerning surface area, the decreasing order series of pillared material was: Ti-PILC > Fe-PILC > AI-PILC. Depression of total surface area and decreasing of basal spacing d₀₀₁, with no modification of basal structure of starting natural clay have been observed due to the incorporation ofFe-Mn active phase into the structures of Ti-PILC and A1-PILC. The Fe-Mn mixed phase supported over pillared material exhibited higher catalytic activity than the Fe-PILC sample, which was attributed to the cooperative effect of Mn. This effect could be associated with redox properties of Mn and improving of surface oxygen mobility. Delaminated structure and strong interaction of Fe with clay porous network into the Fe-PILC sample could be the reason of lower activities. However, higher performances were observed in the case of Fe oxide nanoparticles prepared with surfactant agent over bentonite, due to a lesser extent of Fe-porous structure interaction presented in these samples.

Keywords : nanoparticles based on Fe oxide; F e- PILC; total combustion of n-hexane.

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