CuZnAl@S-1 Catalyst for the Synthesis of Higher Alcohols by CO Hydrogenation

The direct conversion of syngas to ethanol using CuZnAlcatalystsis very challenging. In this paper, CuZnAl@S-1, CuZn@S-1, ZnAl@S-1,and CuAl@S-1 catalysts were prepared using a solid-phase method toprepare silicate-1 molecular sieves with Cu, Zn, and Al componentsencapsulated in them, and their catalytic performance for CO hydrogenationwas evaluated in a fixed-bed reaction. The structural and surfaceproperties of the catalysts were characterized using X-ray diffraction,transmission electron microscopy, N-2 physisorption, andX-ray photoelectron spectroscopy and correlated with the catalyticperformance. The results showed that the use of structurally simpleS-1 immobilized CuZnAI nanoparticles (CZA@S-1) was effective in enhancingthe conversion of ethanol, where C2+OH/ROH up to 50.63%and ROH selectivity up to 27.27% were achieved, and no deactivationwas observed within six days. The characterization results indicatethat the interaction between CuZn in the CZA@S-1 catalysts is strongerthan that between CuAl and ZnAl, that the CuZn active component isable to supply electrons to the molecular sieve, and that the core-shellstructure promotes the adsorption and dissociation of CO and enhancesC-C coupling. In situ diffuse reflectance infrared Fouriertransform spectroscopy measurements of the reaction intermediatesfor each catalyst inferred a pathway for C-C coupling to ethanol,which provides an alternative pathway to the CuZnAl conventional catalyst.