Grisel Corro

An XPS evidence of Pt4+ present on sulfated Pt/Al2O3 and its effect on propane combustion

Abstract The nature of the active sites of non-sulfated and sulfated 1%Pt/γ-Al2O3 has been investigated for the combustion of propane. An enhancement in the activity for propane oxidation was confirmed with the sulfated catalyst. FTIR spectroscopy proved the formation of sulfate species in the catalyst surface. XPS results revealed an increased formation of a highly oxidized Pt species over sulfated 1%Pt/γ-Al2O3 that suggests that the promoting effect on the propane combustion is due to the interaction of surface sulfates with surface highly oxidized Pt atoms that can be ascribed to Pt4+ at the edge of the Pt particles.

Promoting and inhibiting effect of SO2 on propane oxidation over Pt/Al2O3

Abstract SO 2 adsorption, SO 2 oxidation and oxidation of propane with oxygen in the absence and the respective presence of SO 2 in the feed gas were studied over unsulfated and sulfated 1% Pt/γ-Al 2 O 3 . Results showed that the promoting effect of SO 2 in the reaction flux on C 3 H 8 oxidation over 1% Pt/γ-Al 2 O 3 depends on the presulfating temperature. Catalytic activity measurements and FTIR absorption spectra showed that during propane oxidation, Pt/support interfacial adsorbed species were formed at temperatures 25–300 °C, inhibiting C 3 H 8 oxidation. However, at higher temperatures these Pt/support interfacial adsorbed species were oxidized, leading to Pt/support interfacial sulfate species, which strongly promote propane oxidation.

Biodiesel production from waste frying oil using waste animal bone and solar heat

A two-step catalytic process for the production of biodiesel from waste frying oil (WFO) at low cost, utilizing waste animal-bone as catalyst and solar radiation as heat source is reported in this work. In the first step, the free fatty acids (FFA) in WFO were esterified with methanol by a catalytic process using calcined waste animal-bone as catalyst, which remains active even after 10 esterification runs. The trans-esterification step was catalyzed by NaOH through thermal activation process. Produced biodiesel fulfills all the international requirements for its utilization as a fuel. A probable reaction mechanism for the esterification process is proposed considering the presence of hydroxyapatite at the surface of calcined animal bones.