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

Area of Science:

• Materials Science
• Chemical Engineering
• Aerospace Engineering

Background:

• Hydroxylammonium nitrate (HAN) is an emerging eco-friendly, high-performance monopropellant for space propulsion.
• High adiabatic temperatures necessitate advanced catalysts for safe and efficient HAN decomposition.

Purpose of the Study:

• To develop and characterize a novel cobalt-doped cerium oxide catalyst for HAN decomposition.
• To evaluate the catalyst's effectiveness, reaction mechanism, and durability.

Main Methods:

• Co-precipitation synthesis of cobalt-doped cerium oxide.
• Characterization using SEM/EDS, XRD, and XPS.
• Thermal analysis (DTA-TG) and evolved gas analysis (FTIR) for decomposition studies.
• Batch reactor tests for catalyst longevity.

Main Results:

• The catalyst demonstrated effective HAN decomposition.
• An in situ Ce³⁺/Ce⁴⁺ ion couple was critical for reactivity.
• The catalyst exhibited superior versatility and durability compared to alumina-supported iridium.

Conclusions:

• Cobalt-doped cerium oxide is a promising catalyst for hydroxylammonium nitrate monopropellant decomposition.
• The catalyst's performance and durability offer advantages for space propulsion applications.