N-Heterocyclic Carbene-Capped Highly Dispersed Pt Nanoparticles for Catalytic Dehydrogenation-Cracking of Decalin toward High Heat Sink

Active fuel cooling is an effective way to overcome the thermal barrier for hypersonic flight. Pt-based nanofluid catalysts are effective in enhancing the chemical heat sink of endothermic hydrocarbon fuels (EHFs) by facilitating a catalytic dehydrogenation-cracking reaction. However, highly-dispersed Pt nanoparticles often face the problem of poor thermal stability in nanofluids. In this work, a NaH-assisted deprotonation method was applied to synthesize N-heterocyclic carbene (NHC)-capped highly-dispersed Pt nanoparticles (Pt@NHC14). The average size of the Pt nanoparticles in optimized Pt@NHC14 was 2.4 nm. Pt@NHC14 exhibited a high heat sink of 3.80 MJ/kg at 725 °C in the quasi-homogeneous conversion of decalin, which was 10% higher than Pt@ILs14 without a deprotonation strategy. This could be ascribed to the dehydrogenation process being promoted, which was verified by a hydrogen yield of 9.5% on highly dispersed Pt of Pt@NHC14, and that is 46% higher than that of Pt@ILs14. This research synthesizes N-heterocyclic carbene-capped highly-dispersed Pt nanoparticles and provides valuable insights into the strong endothermic technology.