Display omitted •Stable Co2C exhibits excellent ethanol selectivity and durability in CO2 hydrogenation.•Strong metal-support interaction (SMSI) obtained by the SiOCo bond formation ensures the stability of Co2C.•The formation of ethanol is derived from the insertion of CO into CHx intermediates.•CO can induce the regeneration and reconstruction of decomposed Co2C on supports. Direct CO2 hydrogenation to ethanol is one of the promising and emerging routes for the transformation of CO2 into value-added chemicals, but it remains a major challenge because of low ethanol selectivity and catalytic stability. In this work, Na-promoted cobalt catalysts supported on different materials (Al2O3, ZnO, AC, TiO2, SiO2, and Si3N4) were evaluated to elucidate the effects of supports. The SiO2- and Si3N4-supported catalysts exhibited efficient generation of ethanol with 18% CO2 conversion and 62% selectivity in the alcohol distribution at 250 °C, whereas CH4 was predominantly produced on other supported catalysts. Characterization results indicated that the Co2C active phase only remained intact on SiO2 and Si3N4 supports during reaction and exhibited excellent durability for 300 h, which was attributed to the existence of a strong metal–support interaction (SMSI) obtained by SiOCo bond formation. In situ DRIFTS results revealed that CO produced on Co2C inserted into CHx intermediates to form ethanol. Moreover, CO as the reactive intermediate could induce the regeneration and reconstruction of decomposed Co2C on the surface for catalytic sustainability.