CO₂ hydrogenation toward toluene methylation for selective para-xylene synthesis.

ABSTRACT: The selective production of high-value para-xylene (PX) through CO₂ hydrogenation-coupled toluene methylation represents a promising strategy for sustainable carbon utilization. Herein, we report a ZnZrO_x & HMCM-22 tandem catalyst that integrates CO₂ hydrogenation with shape-selective toluene methylation. The optimized catalyst achieves 91% xylene selectivity with 70.4% PX dominance at 10.3% toluene conversion. Controlled tetraethyl orthosilicate (TEOS) deposition passivates Brønsted acid sites in HMCM-22 supercages, suppressing toluene disproportionation while preserving methylation activity in sinusoidal channels. Mechanistic studies reveal that formaldehyde species, generated on ZnZrO_x and transferred to HMCM-22, act as kinetically favored met

SUBMITTER: Tian J 

PROVIDER: S-EPMC12848092 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature