Syngas-to-C2 oxygenates over the inverse Mo6C4/Cu catalyst: Identifying the role of synergistic effect

Abstract

Syngas transformation into C2 oxygenates has attracted a long-term interest, however, it still faces the challenge of low selectivity and yield toward C2 oxygenates. In this study, the inverse Mo6C4/Cu catalyst is reasonably modeled and predicted to promote C2 oxygenates formation in syngas transformation using DFT calculations with the PBE functional. The results confirmed that the inverse Mo6C4/Cu catalyst not only greatly elevates catalytic performance toward CHx(x = 2, 3) monomer formation, but also facilitate C2 oxygenate production compared to the previously reported Cu4/β-Mo2C, β-Mo2C and Cu catalysts, which is attributed to the synergistic effect of Mo6C4 cluster with Cu catalyst, specifically, Mo6C4 cluster easily activates CO to produce CH2 monomer, Cu offers the undissociated CO migrated toward Mo6C4 cluster, then, CO insertion into CH2 to CH2CO over Mo6C4 cluster easily occurs. Our results offer a theoretical basis for the synergistic effect between Mo6C4 cluster with Cu catalyst in tuning catalytic performance of syngas transformation and gives a new way to rationally design the inverse catalyst with excellent performance for C2 oxygenate production from syngas.