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

Abstract

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.