CuCl2/FeCl3 Bimetallic Photocatalyst for Sustainable Ethylene Production from Ethanol via Recoverable Redox Cycles.

Photocatalytic conversions of ethanol to valuable chemicals are significant organic synthesis reactions. Herein, we developed a CuCl2/FeCl3 bimetallic photocatalyst for sustainable dehydration of ethanol to ethylene by recoverable redox cycles. The selectivity of ethylene was 98.3% for CuCl2/FeCl3, which is much higher than that of CuCl2 (34.5%) and FeCl3 (86.5%). Due to the ligand-to-metal charge transfer (LMCT) process involved in generating the liquid products, the CuCl2/FeCl3 catalyst will be reduced to CuCl/FeCl2. Oxygen (O2) is required for the recovery of CuCl2/FeCl3 to avoid exhaustion. The soluble Fe3+/Fe2+ redox species deliver catalyst regeneration properties more efficiently than single metal couples, making a series of redox reactions (Cu2+/Cu+, Fe3+/Fe2+, and O2/ethanol couples) recyclable with synergistic effects. A flow reactor was designed to facilitate the continuous production of ethylene. The understanding of bimetallic synergism and consecutive reactions promotes the industrial application process of photocatalytic organic reactions.