Toward Understanding and Simplifying the Reaction Network of Ketene Production on ZnCr2O4 Spinel Catalysts

It was found experimentally that a reduced ZnCr2O4 spinel performs well in syngas conversion to ketene (CH2CO), which is a key intermediate for ethylene production. In this work, we have systematically investigated the stability of several ZnCr2O4 spinel surfaces by using first-principles calculations. It was identified via microkinetic modeling that the partially reduced ZnCr2O4 (111) surface is preferable to produce ketene. According to the microkinetic modeling, the key of ketene production is the coupling between CH2* and CO*. However, half of the reactive sites were covered by CH3CO* at a steady state, which is formed through the coupling of CH3* and CO*, while it is hard to dehydrogenate to CH2CO. Finally, we propose a global optimization algorithm for ranking the importance of elementary reactions and pathways, which can be considered as a useful tool for simplifying the reaction network and rational design of catalysts in the future.

Automated summary

Experimental and computational studies have shown that a reduced ZnCr2O4 spinel is effective in converting syngas to ketene, a crucial intermediate in ethylene production. Microkinetic modeling identified the partially reduced ZnCr2O4 (111) surface as optimal for ketene production through the coupling of CH2* and CO*, despite hindrance from CH3CO* coverage and dehydrogenation challenges. A proposed global optimization algorithm may assist in ranking elementary reactions and pathways, aiding in simplifying reaction networks and enhancing catalyst design.