Enhancing the Catalytic Performance of Platinum-Doped Lanthanum Hexaaluminate through Reduction Method Variation

Abstract

The development of a catalyst for the ammonium dinitramide (ADN)-based monopropellant system has been of growing interest in space research. In this study, we investigated the development methodology for the platinum hexaaluminate (Pt–LHA) catalyst. The reduction of Platinum was performed in muffle and tubular furnaces by considering the different heating rates, with or without hydrogen gas flow conditions. The dispersion of Platinum on LHA was confirmed by using SEM analysis; the particle size of Platinum in Pt–LHA-1 and Pt–LHA-11 was 5.1–9.1 μm and <100 nm, respectively. Notably, agglomeration of Platinum was observed when the catalyst was calcinated in a muffle furnace without air or H2 gas flow. Interestingly, the even dispersion of Platinum was revealed when the catalyst was calcinated in a tubular furnace at 4% H2 in N2 gas flow. As a result, Pt–LHA-7 to Pt–LHA-11 exhibited higher catalytic activity than Pt–LHA-1 to Pt–LHA-6 under H2O2 reactor conditions. The catalyst Pt–LHA-9 was further tested in a 1 N ADN thruster, demonstrating its capability to decompose the ADN-based monopropellant in an operation thruster.