Structure of Na Species in Promoted CaO-Based Sorbents and Their Effect on the Rate and Extent of the CO2 Uptake
OPEN ACCESS
Loading...
Author / Producer
Date
2023-10-02
Publication Type
Journal Article
ETH Bibliography
yes
Citations
Altmetric
OPEN ACCESS
Data
Abstract
To advance CaO-based CO₂ sorbents it is crucial to understand how their structural parameters control the cyclic CO₂ uptake. Here, CaO-based sorbents with varying ratios of Na₂CO₃:CaCO₃ are synthesized via mechanochemical activation of a mixture of Na₂CO₃ and CaCO₃ to investigate the effect of sodium species on the structure, morphology, carbonation rate and cyclic CO₂ uptake of the CO₂ sorbents. The addition of Na₂CO₃ in the range of 0.1–0.2 mol% improves the CO₂ uptake by up to 80% after 10 cycles when compared to ball-milled bare CaCO₃, while for Na₂CO₃ loadings >0.3 mol% the cyclic CO₂ uptake decreases by more than 40%. Energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy, X-ray absorption spectroscopy (XAS), and ²³Na MAS NMR, reveal that in sorbents with Na₂CO₃ contents <0.3 mol% Na exists in highly distributed, noncrystalline [Na₂Ca(CO₃)₂] units. These species stabilize the surface area of the sorbent in pores of diameters >100 nm, and enhance the diffusion of CO₂ through CaCO₃. For Na₂CO₃ contents >0.3 mol%, the accelerated deactivation of the sorbents via sintering is related to the formation of crystalline Na₂Ca(CO₃)₂ and the high mobility of Na.
Permanent link
Publication status
published
External links
Editor
Book title
Journal / series
Volume
33 (40)
Pages / Article No.
2302916
Publisher
Wiley-VCH
Event
Edition / version
Methods
Software
Geographic location
Date collected
Date created
Subject
CaO; Na; Na2CO3; promotion; sorbents; species; structures
Organisational unit
03865 - Müller, Christoph R. / Müller, Christoph R.
03872 - Copéret, Christophe / Copéret, Christophe
Notes
Funding
819573 - Advancing CO2 Capture Materials by Atomic Scale Design: the Quest for Understanding (EC)
180544 - NCCR Catalysis (phase I) (SNF)
180544 - NCCR Catalysis (phase I) (SNF)