Cerium oxide based active catalyst for hydroxylammonium nitrate (HAN) fueled monopropellant thrusters

Agnihotri, Ruchika; Oommen, Charlie

doi:10.1039/c8ra02368a

Cited by 23 publications

(36 citation statements)

References 39 publications

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“…The procedure to prepare catalysts used in the present study is reported in our earlier work [21]. Iridium catalyst (Ir/γ‐Al 2 O 3 ) was prepared by wet impregnation of gamma alumina support (make Alfa Aesar; surface area (200 m 2 /g) catalyst pellets) using hexachloroiridic acid as active metal precursor.…”

Section: Methodsmentioning

confidence: 99%

“…Iridium catalyst (Ir/γ‐Al 2 O 3 ) was prepared by wet impregnation of gamma alumina support (make Alfa Aesar; surface area (200 m 2 /g) catalyst pellets) using hexachloroiridic acid as active metal precursor. Cerium oxide catalyst was prepared from ceric ammonium nitrate and cobaltous nitrate by coprecipitation method followed by sintering of prepared pellets as reported earlier [21].…”

Section: Methodsmentioning

confidence: 99%

“…Many of these catalysts were found untenable as extreme temperature levels and rapid pressure pulses along with corrosive nitric acid were found to curtail the life of catalysts significantly [29, 32–34]. However, the catalyst that was developed in‐house in our laboratory was found robust with almost zero degeneration when compared to iridium catalyst [21]. Since the cobalt doped ceria catalyst is uniquely positioned in terms of its reactivity, in initiating and sustaining high temperature reaction, we decided to explore further the reaction mechanisms involved during the catalytic decomposition of HAN using thermal techniques, specifically exploring the low temperature decomposition.…”

Section: Introductionmentioning

confidence: 91%

“…The changeover from hydrazine to HAN is technologically challenging as high temperature tolerant catalysts and structural materials are to be developed. We have recently reported a new high temperature tolerant catalyst based on cobalt doped cerium oxide which was found to be both thermally and chemically stable under monopropellant decomposition conditions [21]. It was found to be highly enduring and resistant to nitric acid formation during HAN decomposition.…”

Section: Introductionmentioning

confidence: 99%

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Kinetics and Mechanism of Thermal and Catalytic Decomposition of Hydroxylammonium Nitrate (HAN) Monopropellant

Agnihotri

Oommen

2021

Propellants Explo Pyrotec

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Hydroxylammonium nitrate (HAN) monopropellant with its low sensitivity, volatility and toxicity, not only promises a safer substitute to hydrazine but also offers a higher specific impulse and a positive oxygen balance. This study primarily explores the decomposition mechanism and underlying kinetics for a newly developed cerium oxide‐based catalyst. The chemical kinetics involved in the thermal and catalytic decomposition was examined through an isoconversional method using thermogravimetric analysis (TG) data. The activation energy (Ea) was evaluated using differential isoconversional method (Friedman's method) and advanced integral isoconversional method (Popescu‐Ortega's method). To find frequency factor, compensation effect method (ACE) and intercept method (A0) were used. Advanced integral method could not provide realistic kinetic parameters while differential method predicted values similar to reported values for thermal decomposition. The values obtained for thermal decomposition were found matching with reported values obtained by other techniques which validated the methodology adopted. The reaction mechanism for both thermal and catalytic decomposition were proposed based on evolved gas analysis. The mechanism proposed was able to describe the variable kinetic parameters extracted from isoconversional method. Overall Ea of thermal decomposition of HAN was ∼95 kJ/mol. The decomposition over ceria‐based catalyst was distributed over three stages namely inception, peak and decay with Ea of ∼33 kJ/mol, ∼170 kJ/mol and ∼130 kJ/mol, respectively. Under identical conditions, iridium‐based catalyst show two decomposition stages with Ea of ∼65 kJ/mol and ∼120 kJ/mol while final stage being evaporation of HNO3. The ceria catalyst favoured N2 formation, increased decomposition of HNO3 and enhanced decomposition enthalpy.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

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Kinetics and Mechanism of Thermal and Catalytic Decomposition of Hydroxylammonium Nitrate (HAN) Monopropellant

Agnihotri

Oommen

2021

Propellants Explo Pyrotec

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“…Recently, ADN-based liquid monopropellants consisting of an ADN aqueous solution, methanol, and ammonia were commercialized [5]. An HAN-based liquid monopropellant was also used in aqueous solutions [6,7]. ADN and HAN are highly energetic compounds, and the decomposition of ADN-and HAN-based 2 of 15 liquid monopropellants does not generate halogen compounds.…”

Section: Introductionmentioning

confidence: 99%

Catalytic Decomposition of an Energetic Ionic Liquid Solution over Hexaaluminate Catalysts

et al. 2019

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The objective of this study was to determine the effect of a synthesis procedure of Sr hexaaluminate on catalytic performance during the decomposition of ionic liquid monopropellants based on ammonium dinitramide (ADN) and hydroxyl ammonium nitrate (HAN). Sr hexaaluminates were prepared via both coprecipitation and a sol–gel process. The surface area of hexaaluminate synthesized via the coprecipitation method was higher than that of hexaaluminate synthesized by the sol–gel process, and calcined at the same temperature of 1200 °C or more. This is because of the sintering of α-Al2O3 on the hexaaluminate synthesized via the sol–gel process, which could not be observed on the catalysts synthesized via the coprecipitation method. The hexaaluminate synthesized via coprecipitation showed a lower decomposition onset temperature during the decomposition of ADN- and HAN-based liquid monopropellants in comparison with the catalysts synthesized via the sol–gel process, and calcined at the same temperature of 1200 °C or more. This is attributed to the differences in the Mn3+ concentration and the surface area between the two hexaaluminates. Consequently, the hexaaluminate synthesized via coprecipitation which calcined above 1200 °C showed high activity during the decomposition of energetic ionic liquid monopropellants compared with the hexaaluminate synthesized via the sol–gel process.

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Impact of HAN Ternary Propellant System Decomposition on Catalytic Sustainability

Agnihotri

Oommen

2021

Propellants Explo Pyrotec

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Aqueous solution of Hydroxylammonium nitrate (HAN) in combination with a suitable fuel has been explored as a promising high performing green monopropellant in recent times. The current study primarily explores the effect of the addition of a fuel component into HAN solution on the sustainability of a recently developed catalyst which was examined for the only binary system consisting of HAN and water. The HAN ternary system examined was HAN: methanol: water in 70 : 15 : 15 (w/w) composition. The endurance of an ‘iridium over alumina’ catalyst and an indigenously developed cobalt doped ceria‐based catalyst was analysed using a batch reactor wherein a pressure rise during decomposition of propellant whilst a pulse mode operation was monitored. Catalysts were also characterized via SEM/EDS, XRD, and XPS to identify changes over the period of sequential injection in the batch reactor. Doped ceria catalyst was found to be far robust and resistant to any poisoning when compared to iridium catalyst at run time of the operation involving nearly 45 sequential injections of propellant over the catalyst.

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Cerium oxide based active catalyst for hydroxylammonium nitrate (HAN) fueled monopropellant thrusters

Abstract: The developed doped ceria catalyst is a new type of high temperature and poisoning resistant catalyst for decomposition of hydroxylammonium nitrate monopropellant.

Cited by 23 publications

References 39 publications

Kinetics and Mechanism of Thermal and Catalytic Decomposition of Hydroxylammonium Nitrate (HAN) Monopropellant

Kinetics and Mechanism of Thermal and Catalytic Decomposition of Hydroxylammonium Nitrate (HAN) Monopropellant

Catalytic Decomposition of an Energetic Ionic Liquid Solution over Hexaaluminate Catalysts

Impact of HAN Ternary Propellant System Decomposition on Catalytic Sustainability

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