‘Scrubbing’ carbon dioxide (CO2) from industrial exhaust gases is one of the critical steps needed to reduce CO2 emissions. It remains a major challenge for researchers, however, to find materials that can reliably soak up CO2 under the extreme conditions common to real-world industrial processes.
A study by Jizhong Luo and co-workers from the A*STAR Institute of Chemical and Engineering Sciences in Singapore now promises to help mitigate CO2 emissions by uncovering never-before-seen structural details of high-temperature sorption materials called layered double hydroxides (LDHs).
Composed of positively charged sheets of metal oxides interspersed with relatively open spaces holding anions and water molecules, LDHs have large, active surfaces that can react with CO2 and transform the gas into solid carbonate ions. Recently, scientists have used LDHs as part of an innovative technology called the sorption-enhanced water-gas shift that combines high-temperature hydrocarbon processing with CO2 removal in a single step. However, when LDHs reach their adsorption limits, they must be regenerated by heating to temperatures high enough to induce an internal structural transformation—a process known as calcination that can eventually destabilize the metal oxide layers.
Luo and his co-workers set out to understand the high-temperature performance of these adsorbents by adjusting the chemical composition of a typical magnesium–aluminum LDH. The researchers replaced the triply charged aluminum cations with iron, gallium and manganese cations and systematically observed how these substitutions affected structure, adsorption and thermal stability. Their results revealed, for the first time, the role such metal species play in LDH-based CO2 fixation.
Surprisingly, the researchers found that the new cations influenced the physical properties of the LDH more than its chemical behavior. “Generally, people may think that differences in chemical composition between LDHs will lead to different CO2 adsorption sites, and therefore different carbon capture capacities,” notes Luo. “However, our research demonstrates that the temperature-dependent structural evolution of LDHs is a much more important parameter.” Luo and his co-workers showed that distinct calcination temperatures for each LDH compound, as well as a unique quasi-amorphous phase, are key to maximizing CO2 adsorption levels.
The empirical ground-rules laid out by this study should help researchers select even better candidates for industrial CO2 scrubbers. “High-temperature CO2 adsorbents are a hot topic right now in carbon capture and sequestration,” Luo says. “In the future, we plan to use combinations of triply charged metal cations to better tune the CO2 capturing performance of LDHs.”
The A*STAR-affiliated researchers contributing to this research are from the Institute of Chemical and Engineering Sciences
 Wang, Q. et al. The effect of trivalent cations on the performance of Mg-M-CO3 layered double hydroxides for high-temperature CO2 capture. ChemSusChem 3, 965–973 (2010).
Gene therapy shows promise for treating Niemann-Pick disease type C1
27.10.2016 | NIH/National Human Genome Research Institute
'Neighbor maps' reveal the genome's 3-D shape
27.10.2016 | International School of Advanced Studies (SISSA)
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
27.10.2016 | Materials Sciences
27.10.2016 | Physics and Astronomy
27.10.2016 | Life Sciences