Hydrogenation of CO2 to alcohol species over Co@Co3O4/C-N catalysts

Co/C-N materials were synthesized with calcination of ZIF-67 at a N2 atmosphere. [email protected]3O4/C-N catalysts were prepared by partially oxidized of Co/C-N in air under different conditions. The catalysts were characterized with XRD, BET, TEM, TGA, H2-TPD, ESR and XPS. The metallic Co in Co/C-N was the main activity site for the CO2 hydrogenation as it supplied dissociative hydrogen on the surface. Partial oxidation of Co/C-N decreased the content of metallic Co, decreasing the amount of dissociative H2 and thus the CO2 conversion, while increasing the methanol selectivity. Oxygen defects in [email protected]3O4/C-N improved the dissociation of CO2 and helped to produce desired alcohol species. The highest yield of MeOH, 2.0 mmol g−1 h−1, was obtained over [email protected]3O4/C-N (250, 2 h) at 220 °C.