Catalytic Decomposition Of Hydrazine Research Articles

Catalytic Decomposition of Hydrazine on Germanium

Catalytic Decomposition of Hydrazine on Germanium

A thermodynamic study on catalytic decomposition of hydrazine in a space thruster

A thermodynamic study on catalytic decomposition of hydrazine in a space thruster

Catalytic Decomposition of Hydrazine and Hydrazine Derivatives to Produce Hydrogen-Containing Gas Mixtures: A Review

Catalytic Decomposition of Hydrazine and Hydrazine Derivatives to Produce Hydrogen-Containing Gas Mixtures: A Review

Defining the optimal morphology of Rhn nanoparticles for efficient hydrazine adsorption: a DFT-D3 study

The catalytic decomposition of hydrazine using metallic nanoparticles has recently attracted considerable attention as this provides a promising means for highly efficient hydrogen release desired for a cleaner economy; however, the efficient catalytic nanoparticles model is still controversial. To shed further light on the optimal morphology of rhodium nanoparticles reported as the most efficient catalyst for this reaction, a more realistic nanocluster (Rhn) model is implemented here to compare the adsorption energies of hydrazine on these nanoclusters using the density functional theory. These nanoclusters (Rhn) comprise a varied number of Rh atom (n = 13–201), with their pre-constructed shapes but further defined by the highest energy optimization. Our calculations unravel that the vertex atoms of an Rhn nanocluster are the most favoured sites for N2H4 adsorption, in comparison with edge atoms or inner atoms of facets. Notably, the computed adsorption energies (Eads) clearly exhibit a linear dependence on their sizes effective particle diameter (r), with the equation Eads = − 1.30 + (− 0.24) r established. Further calculations on the introduction of adatoms to the regular nanoclusters demonstrated that the stepped facet plays a decisive role in determining the adsorption energy. Moreover, the electronic structure and charge transfer calculations revealed the dative-type binding nature of the N–Rh bond. These results highlight the importance of a more realistic particle model used for such adsorption studies and provide new insights into the design and development of nanocatalysts for the decomposition of hydrazine.

Adsorption and catalytic decomposition of hydrazine on metal-free SiC3 siligraphene

The catalytic decomposition of hydrazine (N2H4) could release lots of energy, and there have been extensive studies on metal surfaces as catalysts for this process. Here, we first reported the detailed mechanisms of adsorption and catalytic decomposition of N2H4 on metal-free nanomaterials with the carbon-based SiC3 siligraphene (g-SiC3) as substrate. By using density functional theory methods, it is found that N2H4 molecule chemically adsorbs on g-SiC3, with the anti configuration as the most stable one. The following analysis show orbital hybridization between N2H4 and g-SiC3. By analyzing the potential energy surfaces, it is revealed that the optimal decomposition pathway of N2H4 on g-SiC3 is mainly the pre-adsorbed NH2 intermediates assisted intermolecular decomposition, with N2 and NH3 as products. The rate determining step of the optimal decomposition pathway is *(N2H3+NH2) → *(NNH2+NH3), which is different from the decomposition pathway of N2H4 on the extensively researched metal surfaces. Our results provide rational principles of metal-free carbon-based catalysts for adsorption and catalytic decomposition of N2H4.

Mechanistic aspects of hydrazine-induced Pt colloid instability and monitoring aggregation kinetics with nanoparticle impact electroanalysis

Here we investigate the mechanistic aspects of Pt nanoparticle (NP) aggregation in solutions typically used for detecting NP/electrode impacts by electrocatalytic amplification (ECA). We previously proposed a general mechanism for Pt colloid destabilization that involved the participation of both the hydrazine redox probe and the pH buffer species as coagulants. Herein the Pt NP coagulation and aggregation mechanisms were further investigated with microscopic kinetic NP concentration monitoring and zeta potential measurements using nanoparticle tracking analysis (NTA), as well as open circuit potential experiments with a citrate-treated polycrystalline Pt surface to assess electrical double layer potential. After considering the combined results of these experiments we propose that the colloidal stability of citrate-capped platinum nanoparticles involves much more than the typical physicochemical interactions predicted by DLVO theory. A structure based on intermolecular H-bonding in the citrate capping layer is the most plausible explanation for the exceptional stability of large Pt NPs in high ionic strength buffers. Thus, the mechanism of Pt NP aggregation includes specific reactive contributions from hydrazine. The catalytic decomposition of hydrazine, in particular, is thought to occur to some extent at the citrate-coated Pt surface while the citrate remains adsorbed. Evolved gases such as ammonia and possible surface bound intermediates from Pt-catalyzed decomposition of hydrazine may disrupt the stability of the citrate layer, causing colloidal instability and thus promoting Pt NP coagulation. In the closing section, we demonstrate nanoparticle impact electroanalysis by ECA detection as a method to quantify Pt NP concentration with adequate time resolution for monitoring the kinetics of Pt NP coagulation.

06/01142 A novel approach for CO-free H 2 production via catalytic decomposition of hydrazine : Zheng, M. et al. International Journal of Hydrogen Energy, 2005, 30, (10), 1081–1089

The aim of this work is to employ niobium oxynitride with macropores generation in the hydrazine decomposition reaction as substitute of iridium supported catalysts used for space communication satellites, which are equipped with microthrusters that control their orbit and attitude. The performance of niobium oxynitride was compared to tungsten oxynitride and Shell 405 catalyst.

Reactivity of platinum nanoaggregates on various types of supports in catalytic decomposition of hydrazine in acid solutions

Platinized catalysts on various types of supports were tested in the catalytic decomposition of hydrazine in HClO4 and HNO3 solutions, where the process follows different pathways. In HClO4, the activity of the catalysts supported on a Termoksid ceramic material is higher than that of the catalysts supported on amorphous silica gel. In nitric acid solutions, the trend is reverse. Peptization of the ceramic supports in acid solutions increasing in the order 75% TiO2-25% SnO2 < 75% TiO2-25% ZrO2 ≪ TiO2 < ZrO2 was observed. In perchloric acid solutions, the catalyst specific activity in the hydrazine adsorption-dissociative decomposition increases with decreasing size of platinum crystallites on the support. In nitric acid solutions, where the hydrazine decomposition proceeds as its catalytic oxidation with nitric acid, the catalyst specific activity decreases with a decrease in the size of the catalyst crystallites, i.e., the catalyst centers located on large crystallites are more active. The results obtained were attributed to the energetic heterogeneity of the surface Pt atoms and various mechanisms of the hydrazine catalytic decomposition in various media.

Catalytic decomposition of hydrazine on iron nitride catalysts

A series of iron nitride catalysts were prepared by a temperature-programmed reaction method and evaluated in a microreactor for hydrazine decomposition. The catalytic activity of iron nitride is apparently higher than those of iron oxide catalysts. The noble-metal-like characteristics of the nitrides might be responsible for the high catalytic activity. The iron nitride catalysts prepared at different temperatures have different bulk structures, whereas they have similar specific catalytic activity per m 2. The iron nitrides with larger surface areas and smaller particle sizes produced higher catalytic activities and H 2 selectivities at high temperatures. The iron nitride catalysts were also compared with the molybdenum nitride and niobium nitride, and the catalytic activities for hydrazine decomposition increase in the order of NbN ≪ FeNx ∼ γ-Mo 2N.

Carbon Nanofiber Composite as a Catalytic Hydrazine Decomposition Support for Satellite Propulsion

The aim of this work is to determine the catalytic performance characteristics of iridium on a carbon nanofiber support with macroscopic shaping in the catalytic decomposition of hydrazine. The obtained performance characteristics obtained are compared with those of a commercial catalyst, Shell 405. Catalytic experiments are carried out in a 2 N microthruster placed inside a vacuum chamber in order to reproduce natural conditions.

Carbon nanostructures with macroscopic shaping for catalytic applications

Carbon nanostructures, nanofibers and nanotubes, with a 1D dimension have witnessed, during the last decade, a large scientific and industrial interest owing to their exceptional physical and chemical properties. Among the different potential applications the use of these carbon nanostructures as catalyst support material seems to be one of the most promising. In the present work, the synthesis and characterisation of a new type of carbon nanofibers (CNF) composite with macroscopic shaping is reported. The CNF composite obtained can be tailored into different macroscopic shapes allowing it to be directly employed in the existing conventional reactors without the problems linked to the small size of the unsupported carbon nanofibers. This material displays a relatively high surface area >100 m 2 g −1, essentially constituted by the external surface, and a complete absence of the bottled pores encountered with traditional solid carriers such as alumina, silica or activated charcoal. The as-synthesized CNF composite was subsequently tested as catalyst support in two reactions, i.e. the catalytic decomposition of hydrazine and the selective oxidation of H 2S into elemental sulfur, where its catalytic performance was largely superior to that obtained on the state-of-the-art traditional catalysts.

Performance comparison of Ir/CNF and Ir/Al2O3 catalysts in a 2 N hydrazine microthruster

The aim of this work is to report the catalytic performances of iridium supported on carbon nanofibre with macroscopic shaping in the catalytic decomposition of hydrazine. The performances obtained are compared to those of the commercial catalyst Shell 405. Catalytic experiments are carried out in a 2 N microthruster. The carbon nanofibre based catalyst shows better activity performances than the commercial one due to its high external surface area and its high thermal conductivity.

A novel approach for CO-free H [formula omitted] production via catalytic decomposition of hydrazine

Supported group VIII (8, 9, and 10) metal catalysts, such as Fe/SiO 2 , Ru/SiO 2 , Co/SiO 2 , Rh/SiO 2 , Ir/SiO 2 , Ni/SiO 2 , Pd/SiO 2 , and Pt/SiO 2 have been prepared for use in the producing of CO-free H 2 via catalytic decomposition of hydrazine. Evaluation of the catalysts was conducted in a fixed-bed continuous-flow microreactor. All of the catalysts could catalyze the decomposition of hydrazine to form H 2 and N 2 at temperatures higher than 300 ∘ C. Differing from the other catalysts, the Ni, Pd, and Pt catalysts were also able to produce hydrogen with very high selectivities under rather mild conditions. Ni/SiO 2 was the best catalyst owing to its high activity and excellent H 2 selectivity of higher than 90% at an initial temperature of ∼ 30 ∘ C. The selectivity was sensitive to the reaction temperature. Low temperatures (30– 60 ∘ C) were favorable for producing H 2 with high selectivity. The preparation method and the support have remarkable influence on the catalytic activity and selectivity of the nickel catalysts. The reasons for such dependences are discussed according to the TPR and H 2 -TPD results of the nickel catalysts.

Catalytic Decomposition of Hydrazine on Tungsten Carbide: The Influence of Adsorbed Oxygen

Passivated and nonpassivated tungsten carbide (WC) powders were prepared by a temperature-programmed reaction and used as catalysts in the hydrazine decomposition reaction. All catalysts were active at 313 K. The only products of reaction were nitrogen and ammonia, suggesting that the reaction route and the rate-determining step were not modified by adsorbed oxygen. Surface oxygen atoms reacted with hydrazine, resulting in a larger decrease in the rate of reaction for the passivated solids. Excess carbon on the surface of the carbide inhibited the decomposition of hydrazine and resulted in a decrease of ca. 48% in the specific surface area of the tungsten carbide. The excess carbon may be removed in flowing hydrogen at 1000 K. When compared to commercial Ir catalyst (Shell 405), WC is less active in the hydrazine decomposition reaction.

Catalytic decomposition of hydrazine over supported molybdenum nitride catalysts in a monopropellant thruster

The catalytic decomposition of hydrazine over a series of MoNx/γ-Al2O3 catalysts with different Mo loadings was investigated in a monopropellant thruster (10 N). When the Mo loading is equal to or higher than the monolayer coverage of MoO3 on γ-Al2O3, the catalytic performance of the supported molybdenum nitride catalyst is close to that of the conventionally used Ir/γ-Al2O3 catalyst. The MoNx/γ-Al2O3 catalyst with a loading of about 23 wt% Mo (1.5 monolayers) shows the highest activity for hydrazine decomposition. There is an activation process for the MoNx/γ-Al2O3 catalysts at the early stage of hydrazine decomposition, which is probably due to the reduction of the oxide layer formed in the passivation procedure.

Nitride and carbide of molybdenum and tungsten as substitutes of iridium for the catalysts used for space communication

Satellites are equipped with microthrusters that control their orbit and attitude. The thrust is achieved by the catalytic decomposition of hydrazine by iridium supported on alumina. As nitrides and carbides of molybdenum and tungsten behave like noble metals in many catalytic reactions, they were tried in a 2 newton hydrazine microthruster. Their performance was similar to that of the iridium catalyst, with respect to ignition delay and thrust. Their mechanical resistance appears higher than that of iridium-based catalyst. This application is the first practical one for nitrides and carbides of early transition metals as substitutes of noble metals, a possibility first reported in 1973.

ChemInform Abstract: INVESTIGATIONS ON THE RUPTURE OF THE N‐N‐BOND WITHIN THE ANODIC OXIDATION AND CATALYTIC DECOMPOSITION OF HYDRAZINE

Chemischer InformationsdienstVolume 5, Issue 20 Physical Inorganic Chemistry ChemInform Abstract: INVESTIGATIONS ON THE RUPTURE OF THE N-N-BOND WITHIN THE ANODIC OXIDATION AND CATALYTIC DECOMPOSITION OF HYDRAZINE K. ARNOLDS, K. ARNOLDSSearch for more papers by this authorJ. HEITBAUM, J. HEITBAUMSearch for more papers by this authorW. VIELSTICH, W. VIELSTICHSearch for more papers by this author K. ARNOLDS, K. ARNOLDSSearch for more papers by this authorJ. HEITBAUM, J. HEITBAUMSearch for more papers by this authorW. VIELSTICH, W. VIELSTICHSearch for more papers by this author First published: May 21, 1974 https://doi.org/10.1002/chin.197420050Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume5, Issue20May 21, 1974 RelatedInformation

Investigations on the Rupture of the N-N-Bond within the Anodic Oxidation and Catalytic Decomposition of Hydrazine

Mass spectrometrical measurements of the off gas composition formed in the anodic oxidation or catalytic decomposition of hydrazine at platinized platinum, Raneynickel and amalgamated sintered nickel as electrocatalysts show that only up to 4% of the oxidation of hydrazine occurs via N -N-bond splitting.

Mass-spectrometric investigation of the formation of di-imide by the catalytic decomposition of hydrazine at low pressures on platinum

Mass-spectrometric investigation of the formation of di-imide by the catalytic decomposition of hydrazine at low pressures on platinum

Polymerization Induced by Catalytic Decomposition of Hydrazine at Palladium Surfaces

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPolymerization Induced by Catalytic Decomposition of Hydrazine at Palladium SurfacesGiuseppe ParravanoCite this: J. Am. Chem. Soc. 1950, 72, 9, 3856–3860Publication Date (Print):September 1, 1950Publication History Published online1 May 2002Published inissue 1 September 1950https://doi.org/10.1021/ja01165a006RIGHTS & PERMISSIONSArticle Views140Altmetric-Citations8LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (540 KB) Get e-Alerts Get e-Alerts