Iron-based catalysts characterization

Temperature-Programmed EXAFS/ XANES Characterization of the Impact of Cu and Alkali Promoters to Iron-Based Catalysts on the Carbide Formation Rate... 

Q. Li, W. Ma, R. He, Z. Mu, Reaction and characterization studies of an industrial Cr-free iron-based catalyst for high-temperature water gas shift reaction, Catal. Today 106 (2005) 52-56. 

The overall goal of this study is to develop superior catalysts suitable for use in modem advanced slurry phase or membrane reactors. Successful investigations have produced an iron-based unsupported catalyst with high activity and extended catalyst life (improved attrition resistance). This catalyst was used by the authors to understand the phase transformations from iron oxide precursors after activation to iron carbide crystallites and to characterize the presence of characteristic amorphous carbon species that have been reported to envelop the spent Fe-FTS catalyst grains in form of surface layers. Previous studies suggest two different phases to be considered as the active phase including iron oxide and a mixture of x snd e -carbides (Table 1) and in some instances minor amounts of metallic iron, however the spatial distribution of the different... 

A. Abu-Sutrah, K. Lappalainen, U. PiitDnen, P. Lehmus, T. Repo, M. Leskela, New bis (imino)pyridine Iron(ll) and Cobalt(n)-based catalysts synthesis, characterization and activity towards polymerization of ethylene. J. Oiganomet. Chem. 648, 55-61 (2002)... 

ErtemMZ, Gagliardi L, Cramer CJ. Quantnm chemical characterization of the mechanism of an iron-based water oxidation catalyst. Chem Sci. 2012 3 1293-1299. 

The catalytic data also indicated a strong dependence of the low hydrocarbons conversion on the catalyst elemental composition. For the Lai, s Fe03 g perovskites, a progressive Fe20s enrichment of the surface was evidenced by XPS characterization when decreasing the lanthanum content of the solid. Such additional undesirable surface iron oxide enrichment induced an inhibiting effect on the catalytic activity. As a result, the most efficient lanthanum iron-based perov-sldte was the stoichiometric LaFe03 mixed oxide [40]. 

DW Matson, JC Linehen, JG Darab, ME Buehler. Nanophase iron-based liquefaction catalysts synthesis, characterization, and model compound reactivity. Energy and Fuels 1994 8 10. 

Deactivation of the copper zeolites under de-NO, conditions was one of the major reasons why the catalyst was never used in a commercial application. Recent environmental legislation intensified the hunt for a water- and sulfur-stable active catalyst One of the most successful preparative methods was reported by HaU and Feng [42, 43]. They reported excellent de-NO, performance based on an iron exchanged ZSM-5 zeolite. The activity was reported to remain constant for extended times, even under high water and sulfur content conditions. The initial catalytic study initiated a whole raft of characterization studies by a number of groups. The interest was significantly increased when it became obvious that there are issues with catalyst preparation reprodudbihty [44, 45]. XAS was crucial in the discussion of the structure of active sites for de-NO, and the site responsible for the high... 

The phenomena presented in this book were discussed in many reviews. For example, Schwarz [13] discussed methods used to characterize the acid base properties of catalysts. The review on sorption on solid - aqueous solution interface by Parks [14] includes also principles of surface science. The book Environmental Chemistry of Aluminum edited by Sposito reviews the solution and surface chemistry of aluminum compounds. Chapter 3 [15] provides thermochemical data for aluminum compounds. Chapter 5 [16] lists the points of zero charge of aluminum oxides, oxohydroxides and hydroxides with many references on adsorption of metal cations and various anions on these materials. Unlike the present book, which is confined to sorption from solution at room temperature, publications on coprecipitation and adsorption from gas phase or at elevated temperatures are also cited there. Brown et al. [17] reviewed on dry and wet surface chemistry of metal oxides. Stumm [18] reviewed sorption of ions on iron and aluminum oxides. The review by Schindler and Stumm [19] is devoted to surface charging and specific adsorption on oxides. Schindler [19] published a review on similar topic in German. Many other reviews related to specific topics are cited in respective chapters. 

All the iron [6.5.6]-P-N-N-P hydrogenation catalysts require activation by an external base. The catalytic profile for achiral complex 32 showed that there is an induction period before rapid catalysis takes place for the TH of acetophenone in basic isopropanol. Unexpectedly, reacting 32 with sodium isopropoxide in either benzene or isopropanol yields the pentadentate ferraaziridine complex 39, which was isolated and structurally characterized (Scheme 10).> This unusual complex is diamagnetic, with... 

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