Catalytic cracking by noble metals is an effective strategy to enhance the cooling capacity of endothermic hydrocarbon fuels (EHFs), but microscopic reaction mechanisms of noble catalysts assisted fuel cracking remain to be elucidated. The reactive molecular dynamics simulation (ReaxFF MD) was employed in this work to investigate the catalytic mechanisms of Pt and Pd in the cracking of a surrogate EHF, i.e. n-dodecane. The results demonstrate that both Pt and Pd catalysts can significantly reduce the apparent activation energies for overall pyrolysis, while Pd demonstrating 72 % superior reduction performance due to the higher absorption with reactants. Specially, excessively high temperatures may lead to catalyst deactivation. With metal catalyst included, the gas-phase product yield and the proportion of hydrogen dominate production increases, which can be ascribed to additional dehydrogenation reactions during the initial cracking of n-dodecane by Pt and Pd, resulting in more H2 and C2H4 formation.

中文翻译：

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深入了解 Pt/Pd 催化热解 n-十二烷的微观机理


贵金属催化裂化是提高吸热烃燃料 （EHF） 冷却能力的有效策略，但惰性催化剂辅助燃料裂化的微观反应机制仍有待阐明。本研究采用反应分子动力学模拟 （ReaxFF MD） 研究 Pt 和 Pd 在替代 EHF（即正十二烷）裂解中的催化机制。结果表明，Pt 和 Pd 催化剂都可以显著降低整体热解的表观活化能，而 Pd 由于对反应物的吸收率更高，因此表现出 72% 的还原性能。特别是，过高的温度可能导致催化剂失活。在包括金属催化剂的情况下，气相产物产率和氢气的比例增加，这可以归因于在 Pt 和 Pd 对正十二烷的初始裂解过程中额外的脱氢反应，导致更多的 H2 和 C2H4 形成。