Ethanol synthesis catalyzed by single Ni atom supported on Mo6S8 support

Abstract

Conversion of carbon monoxide (CO) into ethanol has attracted significant interest due to ethanol can be used as alternative energy sources to satisfy the rising global energy demands and to solve the serious environmental problems, although it suffers from slow kinetics and low selectivity. Metal single-atom catalyst of Ni single atom supported on Mo6S8 (Ni-SA/Mo6S8) catalyst was developed for the exclusive conversion of CO into ethanol. Herein, ethanol synthesis on Ni-SA/Mo6S8 was systematically investigated using density functional theory (DFT) and microkinetic modeling. The adsorption situations and the reaction routes for ethanol reactions on Ni-SA/Mo6S8 were clarified. Interestingly, the selectivity to ethanol is controlled by CH3 formation and CC bond formation between CH3 species and CHO. Our results indicated that Ni-SA/Mo6S8 increases the stability of the reaction intermediates, and CH3 is the most favorable formed by CH3OH dissociation. Then CHO insertion into CH3 to form CH3CHO* is spontaneous, which suggested that the formation of ethanol is the most favorable on the Ni-SA/Mo6S8 catalyst. The BEP relationships of five different types of bonds in ethanol synthesis identified CO bond scission does not readily occur compared to the other four types of bonds, the formation of CH, OH, and CC bonds are easy to occur. Microkinetic modeling also confirmed Ni-SA/Mo6S8 shows extremely activity and selectivity for ethanol formation. We hope our study can provide the basis to understand and develop single-atom catalysis for ethanol synthesis.