Understanding 3D volumetric analysis of active MOF embedded in thin film polymer

Metal organic frameworks (MOFs) are a structurally tuneable class of hierarchical porous materials with a wide range of host-guest chemistry [1].

MOFs are incredibly difficult to structurally characterise using typical scanning electron microscopy methods. Beam stability, along with non-conductive nature and porous framework result in a combination of problematic issues for nanoimaging and structural milling.

We demonstrate a novel technique to imaging, 3D volumetric chemical analysis using MOF-74 type analogue for carbon capture and mixed membrane composite CPO-27-Ni [2,3]. Using imaging strategies that include high resolution variable pressure microscopy with optimised beam path lengths using NanoVP charge reduction mode, we demonstrate superior imaging at a low vacuum, improving imaging quality and eliminating sample charging. Alongside this we employ a cryogenically cooled in situ stage to undertake 3D volumetric analysis of a MOF composite membrane in conjunction with energy dispersive x-ray spectroscopy. In doing so we show a new methodology for 3D volumetric analysis of MOF composites and best practice imaging using low pressure, low kV scanning electron microscopy.

REFERENCES

[1] Baumann, A. E., Burns, D. A., Liu, B., & Thoi, V. S. (2019). Metal-organic framework functionalization and design strategies for advanced electrochemical energy storage devices. Communications Chemistry, 2(1), 86.

[2] Choe, J. H., Kim, H., & Hong, C. S. (2021). MOF-74 type variants for CO2 capture. Mater. Chem. Front.

[3] Vornholt, S. M., Duncan, M. J., Warrender, S. J., Semino, R., Ramsahye, N. A., Maurin, G., Smith, M. W., Tan, J.-C., Miller, D. N., & Morris, R. E. (2020). Multifaceted Study of the Interactions between CPO-27-Ni and Polyurethane and Their Impact on Nitric Oxide Release Performance. ACS Applied Materials & Interfaces, 12(52).