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

The Interaction of Water with Solid Surfaces: Fundamental Aspects Revisited

A review of the aqueous electrochemical reduction of CO2 to hydrocarbons at copper

http://w0.rz-berlin.mpg.de/hjfdb/pdf/172e.pdf

Surface chemistry of carbon dioxide

http://ntur.lib.ntu.edu.tw/bitstream/246246/172223/1/23.pdf

Characterization of cobalt oxides studied by FT-IR, Raman, TPR and TG-MS

The effect of preadsorbed Cs on the electronic structure and thermal stability of CO adsorbed at 80 K on Fe(110) has been studied using ultraviolet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS). With increasing Cs coverage the O1s and C1s core levels of CO are shifted to lower binding energies (-0.8 eV). In the presence of one-monolayer Cs the thermal stability of CO is enhanced, leading to a decomposition temperature of about 510 K, a value roughly 100 K higher than on the clean Fe(110) surface (~ 420 K). This is explained in terms of an increased back-donation leading to an electrostatic interaction between CO and Cs. These results are compared to the properties of CO which is formed when CO2 is adsorbed on the Cs-precovered Fe(110) surface, CO formed from adsorbing CO2 shows neither core level binding energy shift nor enhanced thermal stability. It is concluded that CO formed from adsorbing CO2 is not affected by the preadsorbed Cs, i.e. there is no or at least significantly less increased backbonding and therefore no electrostatic interaction between Cs and CO in that system. It seems to be in a state comparable to the state of CO in the Fe(110)/CO adsorption system.

Co as Adsorbate and Reaction Product in the Systems Fe(110)/Cs+Co and Fe(110)/Cs+Co2

The effect of electron beam irradiation with energies ranging between 1000 and 2000 eV on adsorbed water molecules was studied in an Auger spectrometer with a single pass CMA. The M23 VV transitions doublet of Cu at 59–61 eV and the LMM transitions between 600 and 940 eV were monitored simultaneously while exposing the Cu sample at 170 or 300 K to water, until the oxygen KLL signal took a steady value. The target current was also monitored intercalating a picoammeter between sample and ground. Both, polycrystalline and Cu(100) samples were studied. As the water exposure progressed, the M23VV doublet became unresolvable and the sample current took even more negative values. A fairly good correlation was found between the oxygen signal and the sample current, or the doublet resolution independently of the sample temperature. The kinetics of the changes suggest, however, that the water molecule must be adsorbed to be dissociated. Annealing at 673 K restores the original doublet resolution. A lateral composit...

AES electron beam induced fragmentation of molecular water adsorbed on copper

The growth of Pd layers on polycrystalline Cu substrate at 176 K and 300 K was studied in an Auger system with facilities for photoelectric work function (WF) measurements and automated data acquisition. The LVV and MVV Auger transitions of Cu, as well as the corresponding MVV and NVV of Pd, were monitored in relation to Pd overlayer thickness, annealing temperature and sputtering time. The ‘local’ WF change, determined through the secondaries' cut-off shift, and the absolute photoelectric WF were also monitored.

The initially linear increase in the Pd atom fraction, with only one break during deposition at 300 K, suggests a Stranski–Krastanov film growth mechanism. The simultaneously monitored Auger M23M45M45 Cu doublet at 59–61 eV changes from the very beginning of the Pd deposition into one broadened peak at 61 eV, possibly owing to a roughness effect. With sputtering, the slope of the Pd concentration at the interface decreases when the temperature of deposition and sputtering increases from 176 K to 300 K, indicating diffusion of Pd even at 300 K. By sputtering with Ar+ ions of 5 keV, a depth resolution of ∼3.2 nm was found. Annealing at T > 473 K causes a rapid diffusion of Pd atoms into the Cu substrate.

The ‘local’ WF is affected dramatically by Pd deposition and sputtering, while the average photoelectric WF is not as sensitive.

AES study of palladium overlayers on polycrystalline copper

The interaction of iron silicide with oxygen has been studied under ultrahigh vacuum conditions by means of X-ray photoelectron spectroscopy (XPS). The XP spectra show unambiguously that oxygen reacts with silicon in the FeSi2 compound. The O1s XP spectra point to a formation of at least two suboxide species SiOx (x < 2) at room temperature. At higher temperatures increasing sharper signals indicate the transition to one suboxide species.

D. Borgmann

Papers

Co as Adsorbate and Reaction Product in the Systems Fe(110)/Cs+Co and Fe(110)/Cs+Co2

AES electron beam induced fragmentation of molecular water adsorbed on copper

AES study of palladium overlayers on polycrystalline copper

Surface Reactivity of Iron Silicide

Desorptionsspektren des Adsorptionssystems Eisen/Stickstoff