The
direct synthesis of ethanol from methanol via precise C–C
coupling is a highly attractive but challenging target. Herein, we
report the selective production of ethanol from methanol in the presence
of syngas (CO/H2) by tandem catalysis over composite catalysts
composed of mordenite (H–MOR) zeolite coated by carbon layer
(H–MOR–DA@C) and Pt–Sn/CNT. This tandem route
starts from methanol carbonylation with CO to acetic acid over H–MOR–DA@C,
followed by acetic acid hydrogenation to ethanol over Pt–Sn/CNT.
The selectivity of ethanol reached up to 60% with a CH3OH conversion of 98%. As compared to the H–MOR–DA matrix,
the side reaction of ethanol dehydration to ethylene is effectively
hindered over composite catalysts with H–MOR–DA coated
by carbon layer. The special “carbon nest” with oxygenated
functional groups such as ester or carboxylic acid, existing on the
surface of H–MOR–DA@C, is crucial to preventing ethanol
from dehydration, and thus improves the ethanol selectivity and catalytic
stability. This work offers an effective strategy for direct synthesis
of ethanol from methanol and design of efficient composite catalysts
for tandem catalysis by controlling the reaction pathway.