Fundamental Insight into Humid CO2 Uptake in Direct Air Capture Nanocomposites Using Fluorescence and Portable NMR Relaxometry

Glory Russell-Parks, Noemi Leick, Maxwell Marple, Nicholas Strange, Brian Trewyn, Simon Pang, Wade Braunecker

Research output: Contribution to journalArticlepeer-review

4 Scopus Citations

Abstract

Direct air capture (DAC) technology is being explored as a pathway for reducing greenhouse gas emissions through the efficient removal of CO2 from the atmosphere. However, there remains a knowledge gap regarding structure-property-performance factors that impact the behavior of these systems in diverse, real-world environments. In aminopolymer-based DAC systems, gas diffusion is tightly coupled with polymer mobility, which is in turn affected by a large matrix of variables, including interactions with the pore wall of the support, nanoconfinement, the presence of co-adsorbates (moisture), and electrostatic cross-links that develop as a function of CO2 chemisorption. Higher-throughput, benchtop techniques for studying and understanding mobility in these systems would lead to more rapid advances in the field. Here, we demonstrate the value of a fluorescence technique for monitoring polymer mobility within nanocomposite capture materials as a function of CO2 and water adsorption in a series of humidified polyethylenimine-Al2O3 composite materials. The approach allows us to correlate changes in mobility with CO2 adsorption kinetics as a function of relative humidity. We further couple this information with NMR relaxometry data attained using a portable single-sided magnetic resonance device, and we employ diffuse reflectance infrared Fourier transform spectroscopy to correlate the formation of different relative amounts of carbamates and carbonates with the environmental conditions. These results provide a blueprint for using benchtop techniques to promote fundamental understanding in DAC systems that can in turn enable more efficient operation in real-world conditions.

Original languageAmerican English
Pages (from-to)15363-15374
Number of pages12
JournalJournal of Physical Chemistry C
Volume127
Issue number31
DOIs
StatePublished - 2023

Bibliographical note

See NREL/JA-5900-86343 for ChemRxiv preprint

NREL Publication Number

  • NREL/JA-5900-86344

Keywords

  • carbon capture
  • direct air capture
  • fluorescence
  • NMR relaxometry
  • poly(ethylenimine)
  • polymer mobility

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