Hollow Multi-Shelled Structures of Co3O4 Dodecahedron with Unique Crystal Orientation for Enhanced Photocatalytic CO2 Reduction

Structure and facet control are considered to be effective routes to enhance catalytic performance. We successfully synthesized hollow multi-shelled structures (HoMSs) of a Co₃O₄ dodecahedron by adopting metal-organic frameworks (MOFs) as templates and using the sequential templating approach (STA). Importantly, owing to the topological arrangement of metal atoms in MOFs, the Co₃O₄ nanocrystals in HoMSs are assembled in the desired orientation, forming a unique shell with dominant exposure of (111) facets. This process is defined as "genetic inheritance" in this work. In addition, these exposed facets possess high activity for photocatalytic CO₂ reduction. Adding this to the properties inherited from HoMSs, i.e., multiple interfaces and strong solar light harvesting, these Co₃O₄ HoMSs present high catalytic activity for CO₂ photoreduction. The catalytic activity of quadruple-shelled (QS) Co₃O₄ HoMSs was about 5 and 3 times higher than that of Co₃O₄ nanoparticles and Co₃O₄ HoMSs without facet control, respectively.