ESR evidence of hydrogen migration on supported metal catalysts
TL;DR: In this paper, it was shown that the resonance at g = 2.10, developed upon heating of noble-metal-supported catalysts in hydrogen, results from the reduction of iron oxide to metallic iron also present on the supported catalyst.
About: This article is published in Journal of Catalysis.The article was published on 1968-06-01. It has received 39 citations till now. The article focuses on the topics: Iron oxide cycle & Iron oxide.
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TL;DR: It is demonstrated that hydrogen doped given MoO3 and WO3 via a facile H-spillover approach, namely, hydrogen bronzes, exhibit strong localized surface plasmon resonances in the visible light region.
Abstract: Heavily doped semiconductors have recently emerged as a remarkable class of plasmonic alternative to conventional noble metals; however, controlled manipulation of their surface plasmon bands toward short wavelengths, especially in the visible light spectrum, still remains a challenge. Here we demonstrate that hydrogen doped given MoO3 and WO3 via a facile H-spillover approach, namely, hydrogen bronzes, exhibit strong localized surface plasmon resonances in the visible light region. Through variation of their stoichiometric compositions, tunable plasmon resonances could be observed in a wide range, which hinge upon the reduction temperatures, metal species, the nature and the size of metal oxide supports in the synthetic H2 reduction process as well as oxidation treatment in the postsynthetic process. Density functional theory calculations unravel that the intercalation of hydrogen atoms into the given host structures yields appreciable delocalized electrons, enabling their plasmonic properties. The plasm...
185 citations
TL;DR: This review is based on a lecture presented at the 13th Colloquim on Chemical Reaction Engineering (13 CCRE), held in Windsor Castle, U.K., and jointly organized by the Working Parties “Chemical Reaction Engineering” and “chemical Engineering in the Applications of Catalysis” of the European Federation of Chemical Engineering.
Abstract: Introduction Evidence has accumulated in the last 20 years that spillover processes play a crucial role in many catalytic phenomena. Four symposia have highlighted the advances of knowledge in this area, and the progressive recognition that the phenomena have extremely important consequences (Delmon et al., 1973; Inui et al., 1993; Pajonk et al., 1983; Steinberg, 1989). In spite of this, very few kinetic models incorporating spillover have been presented. Little attention, if any, is given to these phenomena in the design of processes or in the definition of operating conditions. ∗Review based on a lecture presented at the 13th Colloquim on Chemical Reaction Engineering (13 CCRE), held in Windsor Castle, U.K., and jointly organized by the Working Parties “Chemical Reaction Engineering” and “Chemical Engineering in the Applications of Catalysis” of the European Federation of Chemical Engineering.
154 citations
TL;DR: In this article, the hydrogen reduction of pure α-Fe 2 O 3 doped with foreign metal oxides employing a sensitive micro-gravimetric technique was carried out by a consecutive two-step mechanism via Fe 3 O 4, the overall rate being controlled by the topochemical reduction of Fe 3 o 4 while that of doped oxides and hematite ore takes place by a different mechanism involving the mixed ferrite formed.
119 citations
TL;DR: In this paper, the synthesis, characterisation and catalytic behaviour of palladium compound derived from Mg/Al hydrotalcite were investigated in the toluene total oxidation.
Abstract: The synthesis, characterisation and catalytic behaviour of palladium compound derived from Mg/Al hydrotalcite were investigated in the toluene total oxidation. The hydrotalcite sample was prepared by co-precipitation of the corresponding chlorides (MgCl2, AlCl3 and H2PdCl4) with boiled fresh water and under N2 atmosphere. Under these conditions, the layered double hydroxide [Mg0.75Al0.25(OH)2]0.25+ PdCl 2 (OH) 2 0.125−x 2 − (CO3)x2−·nH2O was formed. Palladium species were inserted as [PdCl2(OH)2]2− complex coming from the partial substitution of Cl with OH. The space interlayer was imposed by CO32− present also as balancing anion. This new hydrotalcite is less stable than classical hydrotalcite Mg/Al without Pd since its destruction took place at a lower temperature. The palladium hydrotalcite calcined at 290 °C exhibited the best catalytic behaviour (activity and selectivity) in the total oxidation of toluene compared with a conventional palladium catalyst.
111 citations
TL;DR: In this paper, the ESR spectra of Mn SiO 2 and Rh-Mn SiO2 compositions were investigated to learn more about the mode of action of the Mn used as a promoter for acetic acid and acetaldehyde formation from synthesis gas over RhSiO 2 catalysts.
103 citations
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