A study on deactivation of Cu–Zn–Al catalyst for higher alcohols synthesis

Abstract

A Cu–Zn–Al catalyst without promoters was prepared using a complete liquid-phase method and tested for a deactivation study in higher alcohols synthesis from syngas. Results showed that the selectivity of higher alcohols first increased from 36.0% to 68.6% then gradually decreased to 14.1% with time on stream. Characterization results showed that Cu species and Zn species had little changes whereas the phase of Al species changed after reaction. It was found that the Al species of the Cu–Zn–Al catalyst changed from AlOOH to Al₂O₃. The phase change weakened CO dissociation and chain growth which led to the decrease of higher alcohols selectivity with time on stream. It was suggested that AlOOH had a function of CO dissociation and chain growth, which favored the formation of higher alcohols, whereas Al₂O₃ had no function of CO dissociation, which caused the formation of methanol.