Syngas-to-C2 oxygenates on Cu-based catalyst: Quantitative insight into the balancing effect of active Cuδ+(0 ≤ δ ≤ 1) sites

Cu-based catalysts can experimentally catalyze the conversion of syngas-to-C2 oxygenates, however, since the chemical state of Cu sites dynamically evolves in the reaction process, no consensus has been reached on the precise roles of active Cuδ+(0 ≤ δ ≤ 1) sites. Here we resolve this long-term dispute with a series of highly comparable Cu catalyst. The results for the first time quantitatively identify the precise role of Cuδ(0 ≤ δ ≤ 1) sites in adjusting the catalytic activity and selectivity of syngas conversion over Cu-based catalysts, which is well illustrated in the view of electronic properties. Our quantitative results show that the moderate valence state Cuδ+(δ = 0.43 and 0.51) sites can highly-active and highly-selective catalyze the conversion of syngas to produce C2 oxygenates, which is also indirectly supported by the reported experiment studies. It is proposed that the balancing effect of Cu0 and Cu+ species in the experiment contribute to high catalytic performance toward the formation of C2 oxygenates. © 2020 Elsevier Ltd