Nanoscopic and Correlative Porosity Analysis by Electron Microscopy of Biobased Porous Materials

Biobased porous materials such as porous biochar or plant-based porous fiber are excellent candidates for applications in the fields of catalysts, energy, environment, etc. Porosity is the pivotal microstructural characteristic of these biomaterials, as it governs not only the capacity to accommodate metal-based active components, but also regulates the diffusion of target molecules. Currently, due to the lack of advanced characterization techniques and statistical analysis algorithms, comprehensive analysis of the nanoscopic porosity of biomaterials and the correlation between porosity and attributes like growth location and origin is often lacking. This results in a limited understanding of the pore structures in these materials. This study takes tobacco biomass as an example to reveal the correlation between microstructure and properties through electron microscopy and mercury intrusion methods, coupled with principal component analysis. The results reveal consistent pore structures across different bake tobacco samples, with an uneven distribution of pore sizes. Bake tobacco from upper and middle plant parts exhibit higher density compared to lower parts, and variations of porosity exist among bake tobaccos from different regions. The rich porous microstructure of bake tobacco based biomaterials has been systematically revealed. This research provides valuable insights for understanding microstructures of biobased porous materials, facilitating improvements of macroproperties. Furthermore, it establishes a foundation for interpreting the microstructure and macroproperties, paving a way for novel design of biobased porous materials for a broad range of applications.