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.

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

Molecular simulation techniques are used to explore and characterize the atomic scale structure, and to predict binding energies and basal spacing of polymer/clay nanocomposites based on polypropylene (PP) and maleated polypropylene (PPMA), montmorillonite (MMT), and different alkylammonium ions (quats) as surfactants. Our evidences suggest that shorter hydrocarbonic chains are more effective in producing favorable binding energies with respect to longer ones, and the substitutions of hydrogen atoms with polar groups on the quaternary ammonium salt (quat) generally results in greater interaction between quat and both polymer and clay. Under the hypothesis, that montmorillonite platelets are uniformly dispersed in a polymer matrix, the modified polypropylene yields higher interfacial strength with clay than neat polypropylene. The use of neat PP and quats with higher molecular volume offer the higher values of the basal spacing and thus, in principle, they should be more effective in the exfoliation process.

Computer simulation of polypropylene/organoclay nanocomposites: characterization of atomic scale structure and prediction of the binding energy

The exploitation of solar energy, an unlimited and renewable energy resource, is of prime interest to support the replacement of fossil fuels by renewable energy alternatives. Solar energy can be used via concentrated solar power (CSP) combined with thermochemical energy storage (TCES) for the conversion and storage of concentrated solar energy via reversible solid–gas reactions, thus enabling round the clock operation and continuous production. Research is on-going on efficient and economically attractive TCES systems at high temperatures with long-term durability and performance stability. Indeed, the cycling stability with reduced or no loss in capacity over many cycles of heat charge and discharge of the material is pursued. The main thermochemical systems currently investigated are encompassing metal oxide redox pairs (MOx/MOx−1), non-stoichiometric perovskites (ABO3/ABO3−δ), alkaline earth metal carbonates and hydroxides (MCO3/MO, M(OH)2/MO with M = Ca, Sr, Ba). The metal oxides/perovskites can operate in open loop with air as the heat transfer fluid, while carbonates and hydroxides generally require closed loop operation with storage of the fluid (H2O or CO2). Alternative sources of natural components are also attracting interest, such as abundant and low-cost ore minerals or recycling waste. For example, limestone and dolomite are being studied to provide for one of the most promising systems, CaCO3/CaO. Systems based on hydroxides are also progressing, although most of the recent works focused on Ca(OH)2/CaO. Mixed metal oxides and perovskites are also largely developed and attractive materials, thanks to the possible tuning of both their operating temperature and energy storage capacity. The shape of the material and its stabilization are critical to adapt the material for their integration in reactors, such as packed bed and fluidized bed reactors, and assure a smooth transition for commercial use and development. The recent advances in TCES systems since 2016 are reviewed, and their integration in solar processes for continuous operation is particularly emphasized.

Recent Advances in Thermochemical Energy Storage via Solid–Gas Reversible Reactions at High Temperature

Nanofluids based on molten carbonate salts for high-temperature thermal energy storage: Thermophysical properties, stability, compatibility and life cycle analysis

ABSTRACT Carbon nanofibre (CNF) is a potential reinforcement in Zn implants. Nevertheless, its poor interfacial compatibility reduces the reinforcement efficiency drastically. In this study, rare earth lanthanum (La) was used as a compatible interface layer between CNF and Zn matrix. On the one hand, La in situ grew on acidified CNF by a chemical synthesis and achieved a firm coordination covalent bond with the oxygenated functional group derived from CNF. On the other hand, La, as an active rare earth element, could carry out the alloying reaction with the Zn matrix, thus forming strong metal bonding. Results showed that the tensile strength of composites was enhanced from 180.2 ± 12.1 to 243.4 ± 10.2 MPa since the La interface layer promoted the transfer of the interfacial shear stress from the Zn matrix to CNF and thereby consumed massive fracture energy. Encouragingly, it simultaneously improved the ductility, as La activated basal slip and improved the dislocation accommodation capacity. Moreover, the Zn implants displayed excellent anti-tumour efficiency.

https://www.tandfonline.com/doi/pdf/10.1080/17452759.2022.2053929?needAccess=true

In situ grown rare earth lanthanum on carbon nanofibre for interfacial reinforcement in Zn implants

Adhesion strength and bonding mechanism of γ-Fe (111)/α-Al2O3 (0001) interfaces with different terminations

Wettability of molten sodium sulfate salt on nanoscale calcium oxide surface in high-temperature thermochemical energy storage

Insight into diffusion-rebonding of Nano-Al2O3 on Fe surface in high-temperature thermal energy storage system

Insight into the strengthening mechanism of α-Al2O3/γ-Fe ceramic-metal interface doped with Cr, Ni, Mg, and Ti

Influence of rheological behavior of molten sodium sulfate on adherent heterogeneous surface on performance of high-temperature thermochemical energy storage

Qicheng Chen

Papers

Adhesion strength and bonding mechanism of γ-Fe (111)/α-Al2O3 (0001) interfaces with different terminations

Wettability of molten sodium sulfate salt on nanoscale calcium oxide surface in high-temperature thermochemical energy storage

Insight into diffusion-rebonding of Nano-Al2O3 on Fe surface in high-temperature thermal energy storage system

Insight into the strengthening mechanism of α-Al2O3/γ-Fe ceramic-metal interface doped with Cr, Ni, Mg, and Ti

Influence of rheological behavior of molten sodium sulfate on adherent heterogeneous surface on performance of high-temperature thermochemical energy storage