Direct Conversion of Syngas to Higher Alcohols over a CuCoAl|t-ZrO2 Multifunctional Catalyst

Selective synthesis of higher alcohols from syngas is promising but remains challenging owing to the low stability and selectivity towards higher alcohols. Here we introduce a CuCoAl|t-ZrO2 (t denotes tetragonal crystal phase) multifunctional catalyst that can achieve an alcohol selectivity of 64.8 % with 79.6 % C2+OH, and a total selectivity of alcohols and olefins to 81.7 %. The proper proximity was tuned to increase selectivity towards alcohols and decrease the selectivity towards hydrocarbons. The lower surface [H*]/[C*] ratio due to the stronger basic sites of the CuCoAl|t-ZrO2 limited alkyl (CHx) species hydrogenation, and promoted CO insertion and carbon chain growth, resulting in improving the alcohols selectivity. Meanwhile, the weaker adsorption of bridge-type adsorbed CO and the lower decomposition rate of multi-bonded adsorbed CO over CuCoAl|t-ZrO2 inhibited hydrocarbon generation. The selective promotion of the reaction route via the synergetic effect between CuCoAl and t-ZrO2 was proposed to boost higher alcohols selectivity. This work may aid the rational design of effective multifunctional catalyst with synergistic effects for tuning selectivity.