CO2 Capture at Medium to High Temperature Using Solid Oxide-Based Sorbents: Fundamental Aspects, Mechanistic Insights, and Recent Advances

Carbon dioxide capture and mitigation form a key part of the technological response to combat climate change and reduce CO₂ emissions. Solid materials capable of reversibly absorbing CO₂ have been the focus of intense research for the past two decades, with promising stability and low energy costs to implement and operate compared to the more widely used liquid amines. In this review, we explore the fundamental aspects underpinning solid CO₂ sorbents based on alkali and alkaline earth metal oxides operating at medium to high temperature: how their structure, chemical composition, and morphology impact their performance and long-term use. Various optimization strategies are outlined to improve upon the most promising materials, and we combine recent advances across disparate scientific disciplines, including materials discovery, synthesis, and in situ characterization, to present a coherent understanding of the mechanisms of CO₂ absorption both at surfaces and within solid materials.

Ultrafast Carbon Dioxide Sorption Kinetics Using Morphology-Controllable Lithium Zirconate

It was reported that the main obstacle of Li₂ZrO₃ as high-temperature CO₂ absorbents is the very slow CO₂ sorption kinetics, which are ascribed to the gradual formation of compact zirconia and carbonate shells along with inner unreacted lithium zirconate cores; accordingly, the "sticky" Li⁺ and O^2- ions have to travel a long distance through the solid shells by diffusion. We report here that three-dimensional interconnected nanoporous Li₂ZrO₃ exhibiting ultrafast kinetics is promising for CO₂ sorption. Specifically, nanoporous Li₂ZrO₃ (LZ-NP) exhibited a rapid sorption rate of 10.28 wt %/min with an uptake of 27 wt % of CO₂. Typically, the k₁ values of LZ-NP (kinetic parameters extracted from sorption kinetics) were nearly 1 order of magnitude higher than the previously reported conventional Li₂ZrO₃ reaction systems. Its sorption capacity of 25 wt % within ∼4 min is 2 orders of magnitude faster than those obtained using spherical Li₂ZrO₃ powders. Furthermore, nanoporous Li₂ZrO₃ exhibited good stability over 60 absorption-desorption cycles, showing its potential for practical CO₂ capture applications. CO₂ adsorption isotherms for Li₂ZrO₃ absorbents were successfully modeled using a double-exponential equation at various CO₂ partial pressures.

DFT simulations of 7Li solid state NMR spectral parameters and Li+ ion migration barriers in Li2ZrO3

Energy barriers for Li⁺ migration in Li₂ZrO₃ as well as GIPAW NMR isotropic spectral parameters for⁷ Li were computed, aiming to provide guidance for the interpretation and prediction of spectra of more complex systems like materials for LIBs.

Structural and CO2capture analyses of the Li1+xFeO2(0 ≤ x ≤ 0.3) system: effect of different physicochemical conditions

α-Li_1+xFeO₂compounds have been synthesized by nitrate decomposition at low temperature. Their CO₂capture were evaluated in CO₂and CO₂+ steam atmospheres. The amount captured in CO₂+ steam atmosphere was 24 wt%, also magnetite was formed.