Mechanistic Insights into Synergistic Catalysis for Aromatic Fuel Component Cracking over [GaO]⁺/HZSM-5 Zeolite

Efficient cracking of the aromatic component in RP-3 fuel is crucial for enhancing heat absorption and mitigating coking under hypersonic flight conditions. However, the intrinsic stability of aromatics renders thermal pyrolysis inefficient and prone to coke formation, while catalytic cracking provides an effective route to promote fuel decomposition and suppress coking. In this work, reactive force field molecular dynamics (ReaxFF-MD) simulations, density functional theory (DFT) calculations, and experiments were conducted to investigate the thermal and catalytic cracking of RP-3 fuel. The results indicate that elevated temperatures accelerate the decomposition of alkanes and cycloalkanes but have limited impact on aromatics. By contrast, HZSM-5 promotes aromatic cracking by lowering the energy barrier of hydrogenation. A systematic comparison of different modification strategies yielded a Brønsted-Lewis cooperative descriptor, correlating acid site cooperation with the rate-determining steps (RDS) of aromatic cracking, identifying [GaO]⁺ as the most effective modifier. The incorporation of [GaO]⁺ generates Lewis-Brønsted acid pairs that promote cracking of aromatic components. Experimental studies further confirm that [GaO]⁺/HZSM-5 delivers higher gas yields and lighter liquid products, demonstrating enhanced cracking activity and anticoking performance. This Brønsted-Lewis synergy enhances aromatic conversion and guides the rational design of zeolite catalysts for efficient catalytic cracking of aromatic fuel components.