Direct Oxidation of Methanol to Polyoxymethylene Dimethyl Ethers over FeMo@HZSM-5 Core–Shell Catalyst

Direct oxidation of methanol to polyoxymethylene dimethyl ethers (PODEn) with longer C–O chains faces a challenge due to difficult matching of active sites. Herein, a core–shell catalyst composed of an iron molybdenum core and a zeolite shell has been designed, successfully realizing methanol oxidation to PODEn. The PODE2–6 selectivity reaches 41.0% at 85.6% methanol conversion over the FeMo@HZSM-5 catalyst. Combined with the designed experiments and characterizations, the special core–shell structure and the synergy between acid sites with different strengths and redox sites are the pivotal factors for promoting the chain growth of the C–O bond.