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Catalytic conversion of the syngas into higher alcohols (HAs) via Fischer–Tropsch (F–T) synthesis is essential due to the widespread applications of HAs. The interfaces of cobalt and cobalt carbide (Co2C) are found to efficiently promote the HAs formation. However, the study on the links between structural evolution of Co–Co2C interfaces and HAs production is still lacking. In this work, Co3O4 with different contents of sodium (Na) as promoters was synthesized and high-pressure F–T reaction (3 MPa) was carried out in the aim of accelerating the Co2C formation and tuning the interfaces of Co–Co2C. XRD, (HR)TEM, ICP, XPS and XAFS were conducted to study the relationship between the variations of Co–Co2C interfaces and HAs production. With the increasing Na contents, the ratios of Co to Co2C decreased as revealed by XAFS and the selectivity of HAs was decreasing. The fitting results from EXAFS revealed that the ratio of Co to Co2C is in direct proportion to the selectivity of HAs. This work provides a theoretical guidance to tune the interfaces of Co–Co2C and improve the HAs production in F–T reaction.

Metal nanoparticle (NP), cluster and isolated metal atom (or single atom, SA) exhibit different catalytic performance in heterogeneous catalysis originating from their distinct nanostructures. To maximize atom efficiency and boost activity for catalysis, the construction of structure–performance relationship provides an effective way at the atomic level. Here, we successfully fabricate fully exposed Pt3 clusters on the defective nanodiamond@graphene (ND@G) by the assistance of atomically dispersed Sn promoters, and correlated the n-butane direct dehydrogenation (DDH) activity with the average coordination number (CN) of Pt-Pt bond in Pt NP, Pt3 cluster and Pt SA for fundamentally understanding structure (especially the sub-nano structure) effects on n-butane DDH reaction at the atomic level. The as-prepared fully exposed Pt3 cluster catalyst shows higher conversion (35.4%) and remarkable alkene selectivity (99.0%) for n-butane direct DDH reaction at 450 °C, compared to typical Pt NP and Pt SA catalysts supported on ND@G. Density functional theory calculation (DFT) reveal that the fully exposed Pt3 clusters possess favorable dehydrogenation activation barrier of n-butane and reasonable desorption barrier of butene in the DDH reaction. Direct dehydrogenation has been a thematic research area resulting from the energy shortage and petroleum gas upgrading scenario. Here, the authors fabricate fully exposed Pt3 clusters and correlate dehydrogenation activity with average coordination number of Pt-Pt bond.