Fig. 4. The structure and performance of bifunctional catalysts.

a–c Proposed structures of bifunctional catalysts. d–f Hydrogenation of CO₂ over bifunctional catalysts, which are integrated methanol synthesis catalyst and zeolites, with different spatial arrangements. (Adapted with permission from Li et al.⁷¹. Copyright (2019) Elsevier); Gao et al.²⁶. Copyright (2017) Springer Nature; Li et al.¹⁶. Copyright (2017) American Chemical Society). g–i TEM and SEM images of bifunctional catalysts. (Reprinted with permission from Li et al.⁷¹. Copyright (2019) Elsevier).