Daniel Gary

Highly conductive Ni steam reforming catalysts prepared by electrodeposition

New highly conductive, active and stable Ni steam reforming catalysts were prepared through a method consisting of the calcination of a hydrotalcite-like compound electrodeposited in a single step on FeCrAlloy foams.

Deactivation of a Pt/γ-Al2O3 catalyst in the partial oxidation of methane to synthesis gas

The deactivation of a Pt/-Al2O3 catalyst used in an industrial plant for the partial oxidation of methane to synthesis gas was investigated. Four samples at different time-on-stream in air were characterized and their catalytic performances were tested in a micro-reactor in order to shed light on the causes and the effects of this deactivation. The high temperatures (about 900 ◦ C) reached while operating in the industrial plant, promoted modifications to the -Al2O3, inducing sintering phenomena and, therefore, deactivation effects. The not used sample showed good values of yield in syngas (compared with equilibrium values), but these performances decreased quickly with time-on-stream.

Catalytic Methane Decomposition over Fe‐Al2O3

The presence of a Fe-FeAl2 O4 structure over an Fe-Al2 O3 catalysts is demonstrated to be vital for the catalytic methane decomposition (CMD) activity. After H2 reduction at 750 °C, Fe-Al2 O3 prepared by means of a fusion method, containing 86.5 wt % FeAl2 O4 and 13.5 wt % Fe(0) , showed a stable CMD activity at 750 °C for as long as 10 h.

Methane‐induced Activation Mechanism of Fused Ferric Oxide–Alumina Catalysts during Methane Decomposition

Activation of Fe2 O3 -Al2 O3 with CH4 (instead of H2 ) is a meaningful method to achieve catalytic methane decomposition (CMD). This reaction of CMD is more economic and simple against commercial methane steam reforming (MSR) as it produces COx -free H2 . In this study, for the first time, structure changes of the catalyst were screened during CH4 reduction with time on stream. The aim was to optimize the pretreatment conditions through understanding the activation mechanism. Based on results from various characterization techniques, reduction of Fe2 O3 by CH4 proceeds in three steps: Fe2 O3 →Fe3 O4 →FeO→Fe0. Once Fe0 is formed, it decomposes CH4 with formation of Fe3 C, which is the crucial initiation step in the CMD process to initiate formation of multiwall carbon nanotubes.

SiC as stable high thermal conductive catalyst for enhanced SR process

1. Abstract Silicon carbide has been chosen as a support for steam methane reforming (SMR). In fact, its good conductive properties may improve the temperature profile, while decreasing the high AT caused by the high endothermicity of the reaction and, at the same time, increasing the heat transfer from external furnace, reactor wall and catalyst particles. 10 wt % Ni was deposited on the SiC support by incipient wetness impregnation. The sample was calcined at different temperatures in order to study both the chemical-physical properties and the interaction between the support and active phases. The sample calcined at 700°C was tested in a SMR laboratory plant under different operative conditions, in order to evaluate the activity and stability with time-on-stream. On a laboratory scale, the catalyst shows good results, although, at very high temperatures (960°C) the support shows a slight SiO 2 formation.

In Situ IR Characterization of CO Interacting with Rh Nanoparticles Obtained by Calcination and Reduction of Hydrotalcite-Type Precursors

Supported Rh nanoparticles obtained by reduction in hydrogen of severely calcined Rh/Mg/Al hydrotalcite-type (HT) phases have been characterized by FT-IR spectroscopy of adsorbed CO [both at room temperature (r.t.) and nominal liquid nitrogen temperature] and Transmission Electron Microscopy (TEM). The effect of reducing temperature has been investigated, showing that Rh crystal size increases from 1.4 nm to 1.8 nm when the reduction temperature increases from 750°C to 950°C. The crystal growth favours the formation of bridged CO species and linear monocarbonyl species with respect to gem-dicarbonyl species; when CO adsorbs at r.t., CO disproportionation occurs on Rh and it accompanies the formation of (CO)2. The role of interlayer anions in the HT precursors to affect the properties of the final materials has been also investigated considering samples prepared from silicate-instead of carbonate-containing precursors. In this case, formation of (CO)2 and CO disproportionation do not occur, and this evidence is discussed in terms of support effect.

New catalysts for the syngas production obtained by hydrotalcite type precursor containing silicate

Publisher Summary Ni and/or Rh based catalysts (ex-HT) derived by hydrotalcite precursor are considered to be effective catalysts in the catalytic partial oxidation (CPO) reaction. This chapter discusses new stable ex-HT catalysts prepared by inserting silicate instead of CO 3 2- anions in the interlayer. The amount of silicates is not limited by the charge balance of the cations, because, an excess of silicates leads to the formation of polysilicate anions. The insertion of silicates affects the structure of the calcined samples, because, unlike CO 3 2- , the silicates remain in the structure and contribute to the formation of the final catalysts. Catalysts with innovative structure are obtained by HT precursor prepared using silicate as interlayer anion. The calcined catalysts showed two phases—a mixed oxide type structure and a new M-silicate structure, where the cations of the active metal are partially soluted. The Rh catalyst prepared by HT silicate was more active and selective than the one prepared by CO 3 2- .

Foam-supported catalysts tailored for industrial steam reforming processes

Abstract Alumina foams coated with Rh/MgAl 2 O 4 spinel active phases have been produced to be used as catalysts in steam reforming processes with improved thermal transfers and limited pressure drops. Those foam-supported catalysts are here fully characterised before and after aging in water-rich atmosphere at elevated temperatures. It is shown that they are stable at any architectural scale: macro- (foam), micro- (coating) and nano- (Rh active phase) structures. Such catalysts are then very promising catalytic loads to be further implemented in industrial units instead of standard loads.