Size-dependent and sensitivity of copper particle in ternary CuZnAl catalyst for syngas to ethanol

Understanding particle size effect of metal on catalysis has great significance in scientific and industrial applications. Herein, CuZnAl catalysts with narrow Cu particle size distribution had been synthesized and investigated for syngas to ethanol. Selectivity toward to C2+OH sharply increased from 8.9% to 60.5% with the increase of Cu size from 11.8 to 38.3 nm, then it slightly increased to 68.6% when further increasing the size to 49.2 nm, which was attributed to the domination of Cu (111) facet and accompanied by the formation of Cu(111)-ZnO interface at larger Cu sizes, thereby weakened hydrogenation activity and facilitated CHx formation. The in-situ DRIFTS experiment revealed that carbon chain growth was processed by the insertion of CO⁎/CHO⁎ into the CHx⁎ and the coupling of CHx⁎ and CO2⁎. These results substantially broaden the understanding the size effect of Cu and provided guidance for design more active Cu-based catalyst for ethanol synthesis.