Recent Advances in Catalysts for the Highly Selective Conversion of Syngas into Para-Xylene
Para-xylene (PX) is a critical chemical feedstock for producing polyesters, plastics, and fibers, with China's 2024 consumption reaching 40 million tons (63% of global total) and an import dependency of 17%. Conventional naphtha-based routes face feedstock security and cost volatility, prompting interest in syngas conversion. This review systematically examines recent catalyst developments for direct syngas-to-PX-rich aromatics, focusing on three systems: Fischer-Tropsch synthesis (FTS) catalyst/zeolite coupling, methanol synthesis catalyst/zeolite synergy, and dual-engine/zeolite catalysis. Critical parameters such as active component electronic structure, promoter effects, and zeolite pore topology are analyzed to reveal governing principles of activity, selectivity, and stability. Reaction mechanisms via olefin, methanol, and dual-intermediate pathways are explored. Current bottlenecks include coordinated optimization of activity and stability, and unclear regulation of PX selectivity. Future research directions are proposed to address these challenges.