The escalating level of atmospheric carbon dioxide is one of the most pressing environmental concerns of our age. Carbon capture and storage (CCS) from large point sources such as power plants is one option for reducing anthropogenic CO(2) emissions; however, currently the capture alone will increase the energy requirements of a plant by 25-40%. This Review highlights the challenges for capture technologies which have the greatest likelihood of reducing CO(2) emissions to the atmosphere, namely postcombustion (predominantly CO(2)/N(2) separation), precombustion (CO(2)/H(2)) capture, and natural gas sweetening (CO(2)/CH(4)). The key factor which underlies significant advancements lies in improved materials that perform the separations. In this regard, the most recent developments and emerging concepts in CO(2) separations by solvent absorption, chemical and physical adsorption, and membranes, amongst others, will be discussed, with particular attention on progress in the burgeoning field of metal-organic frameworks.

Carbon Dioxide Capture: Prospects for New Materials

Since the time of the industrial revolution, the atmospheric CO(2) concentration has risen by nearly 35 % to its current level of 383 ppm. The increased carbon dioxide concentration in the atmosphere has been suggested to be a leading contributor to global climate change. To slow the increase, reductions in anthropogenic CO(2) emissions are necessary. Large emission point sources, such as fossil-fuel-based power generation facilities, are the first targets for these reductions. A benchmark, mature technology for the separation of dilute CO(2) from gas streams is via absorption with aqueous amines. However, the use of solid adsorbents is now being widely considered as an alternative, potentially less-energy-intensive separation technology. This Review describes the CO(2) adsorption behavior of several different classes of solid carbon dioxide adsorbents, including zeolites, activated carbons, calcium oxides, hydrotalcites, organic-inorganic hybrids, and metal-organic frameworks. These adsorbents are evaluated in terms of their equilibrium CO(2) capacities as well as other important parameters such as adsorption-desorption kinetics, operating windows, stability, and regenerability. The scope of currently available CO(2) adsorbents and their critical properties that will ultimately affect their incorporation into large-scale separation processes is presented.

Adsorbent Materials for Carbon Dioxide Capture from Large Anthropogenic Point Sources

Ordered mesoporous materials in catalysis

Post-combustion CO2 capture from the flue gas is one of the key technology options to reduce greenhouse gases, because this can be potentially retrofitted to the existing fleet of coal-fired power stations. Adsorption processes using solid sorbents capable of capturing CO2 from flue gas streams have shown many potential advantages, compared to other conventional CO2 capture using aqueous amine solvents. In view of this, in the past few years, several research groups have been involved in the development of new solid sorbents for CO2 capture from flue gas with superior performance and desired economics. A variety of promising sorbents such as activated carbonaceous materials, microporous/mesoporous silica or zeolites, carbonates, and polymeric resins loaded with or without nitrogen functionality for the removal of CO2 from the flue gas streams have been reviewed. Different methods of impregnating functional groups, including grafting techniques and modifying the support materials, have been discussed to en...

Post-Combustion CO2 Capture Using Solid Sorbents: A Review

Dry (CO2) reforming of methane (DRM) is a well-studied reaction that is of both scientific and industrial importance. This reaction produces syngas that can be used to produce a wide range of products, such as higher alkanes and oxygenates by means of Fischer–Tropsch synthesis. DRM is inevitably accompanied by deactivation due to carbon deposition. DRM is also a highly endothermic reaction and requires operating temperatures of 800–1000 °C to attain high equilibrium conversion of CH4 and CO2 to H2 and CO and to minimize the thermodynamic driving force for carbon deposition. The most widely used catalysts for DRM are based on Ni. However, many of these catalysts undergo severe deactivation due to carbon deposition. Noble metals have also been studied and are typically found to be much more resistant to carbon deposition than Ni catalysts, but are generally uneconomical. Noble metals can also be used to promote the Ni catalysts in order to increase their resistance to deactivation. In order to design catalysts that minimize deactivation, it is necessary to understand the elementary steps involved in the activation and conversion of CH4 and CO2. This review will cover DRM literature for catalysts based on Rh, Ru, Pt, and Pd metals. This includes the effect of these noble metals on the kinetics, mechanism and deactivation of these catalysts.

A review of dry (CO2) reforming of methane over noble metal catalysts

Adsorption characteristics of carbon dioxide on organically functionalized SBA-15

Production of synthesis gas via methane reforming with CO2 on noble metals and small amount of noble-(Rh-) promoted Ni catalysts

In CH4 dry reforming, the influence of Ca on the activity of supported Ni catalyst depended on the properties of the supports (SiO2, α-Al2O3, γ-Al2O3) and on the amount of Ca added. Small amounts of Ca increased the activity and stability of Ni/α-Al2O3. Temperature-programmed reduction with H2 (H2-TPR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) characterizations of Ca-promoted Ni/α-Al2O3 catalysts indicated that Ca improved the dispersion of Ni, strengthened the interaction between Ni and Al2O3, and retarded the sintering. A higher amount of Ca covered the surface of α-Al2O3 and enhanced the decomposition of CH4.

Tatsuaki Yashima

Papers

Adsorption characteristics of carbon dioxide on organically functionalized SBA-15

Production of synthesis gas via methane reforming with CO2 on noble metals and small amount of noble-(Rh-) promoted Ni catalysts

Characterization of Ca-promoted Ni/α-Al2O3 catalyst for CH4 reforming with CO2

A Novel Titanosilicate with MWW Structure: II. Catalytic Properties in the Selective Oxidation of Alkenes

Alkylation on synthetic zeolites: III. Alkylation of toluene with methanol and formaldehyde on alkali cation exchanged zeolites