Oleylamine-protected metal (Pt, Pd) nanoparticles for pseudohomogeneous catalytic cracking of JP-10 jet fuel

Catalytic cracking of hydrocarbon fuels is an effective way to cool aircraft materials under hypersonic flight. Pseudohomogeneous catalysis is an alternative to overcome the problems of traditional catalyst coatings. Herein, we employed the Brust-Schiffrin method to synthesize Pt and Pd nanoparticles (NPs) using oleylamine as the protecting ligand. The particle size can be controlled by tuning the ratio of protecting ligand, and uniform NPs can be obtained at an oleylamine/NP molar ratio of 2, with Pt and Pd NPs of 1-3 and 2-5 nm, respectively. IR and TG characterizations confirmed that the amine group of oleylamine is chelated on the metal surface whereas the hydrophobic carbon chain is exposed in the hydrocarbon fuel. As a result, the NPs are highly dispersible in jet fuel JP-10 without any precipitation after standing 12 months, providing the possibility of pseudohomogeneous catalysis. Suspensions containing Pt and Pd NPs (50 ppm) exhibited markedly enhanced cracking performance, with cracking conversions, gas yields, and heat sinks at 680 °C that were, respectively, 4.5, 4.4, and 1.3 and 3.1, 3.6, and 1.2 times of pure JP-10. In particular, Pt NPs can reduce the onset temperature of the cracking reaction from 650 to 600 °C. This work demonstrates the potential of fuel-dispersible NPs in hypersonic applications.