Synthesis of Ethanol via Syngas on Cu/SiO₂ Catalysts with Balanced Cu⁰–Cu⁺ Sites

TLDR

The catalysts’ remarkable stability and efficiency stem from a lamellar structure and cooperative Cu⁰–Cu⁺ sites produced by an ammonia‑evaporation hydrothermal method. The study introduces an emerging syngas‑to‑ethanol route yielding ~83 % using Cu/SiO₂ catalysts. The route employs Cu/SiO₂ catalysts prepared by ammonia‑evaporation hydrothermal synthesis, with Cu⁰ and Cu⁺ sites formed during reduction from CuO and copper phyllosilicate. Cu⁰ is the primary active site driving activity, while Cu⁺ co‑exists; the ethanol/ethylene‑glycol selectivity is adjustable by reaction temperature.

Abstract

This paper describes an emerging synthetic route for the production of ethanol (with a yield of ∼83%) via syngas using Cu/SiO2 catalysts. The remarkable stability and efficiency of the catalysts are ascribed to the unique lamellar structure and the cooperative effect between surface Cu0 and Cu+ obtained by an ammonia evaporation hydrothermal method. Characterization results indicated that the Cu0 and Cu+ were formed during the reduction process, originating from well-dispersed CuO and copper phyllosilicate, respectively. A correlation between the catalytic activity and the Cu0 and Cu+ site densities suggested that Cu0 could be the sole active site and primarily responsible for the activity of the catalyst. Moreover, we have shown that the selectivity for ethanol or ethylene glycol can be tuned simply by regulating the reaction temperature.