• • Tandem MgO/ZSM-5 catalysis increased total light aromatics yield by ~20% over ZSM-5 alone, reaching 21.5 mg/g, while maintaining liquid product proportion at 21.4%.
• • MgO's strong basicity enhances pre-cracking and deoxygenation of volatiles, reducing the burden on ZSM-5 and mitigating coke formation, thereby extending catalyst lifespan.
• • The two-layer configuration allows large oxygenated molecules to be fragmented into smaller species that can enter ZSM-5 micropores, improving overall catalytic efficiency.
• • The study demonstrates a practical strategy for upgrading low-rank coal pyrolysis tar into high-value light aromatics, simplifying downstream processing and improving process economics.