Hierarchical porosity via layer-tunnel conversion of macroporous δ-MnO₂ nanosheet assemblies.

ABSTRACT: This work reports the layer-tunnel conversion of porous dehydrated synthetic alkali-free δ-MnO₂ analogs prepared by exfoliation, flocculation, and heat treatment of nanosheets derived from highly crystalline potassium birnessite. High surface area porous solids result, with specific surface areas of 90-130 m² g^-1 and isotherms characteristic of both micro and macropores. The microstructures of the re-assembled floccules are reminiscent of crumpled paper where single and re-stacked nanosheets form the walls of interconnected macropores. The atomic and local structures of the floccules heat treated from 60-400 °C are tracked by Raman spectroscopy and synchrotron X-ray total scattering measurements. During heating, the nanosheets comprising the pore walls cond

SUBMITTER: Metz PC 

PROVIDER: S-EPMC9047169 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature