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.