Adsorption of CO₂on Model Surfaces of Cesium Oxides Determined from First Principles

Abstract

Gradient-corrected periodic density functional theory was used to examine the bulk and low index surfaces of several cesium oxides (Cs 2 O, Cs 2 O 2 , and CsO 2 ). The adsorption of CO 2 on those surfaces was explored. The cesium-terminated {001} surface of Cs 2 O had a weak affinity for CO 2 with an adsorption strength of only -4.1 kJ mol -1 . In contrast, the Cs 2 O {010} surface exposing both Cs and O atoms adsorbed CO 2 with a strength of -284 kJ mol -1 . The adsorption of CO 2 in the bridged configuration on the {001} and the {100} surfaces of Cs 2 O 2 exhibited adsorption strengths of -101 and -186 kJ mol -1 , respectively. The oxygen-rich CsO 2 surface failed to adsorb CO 2 . Results from a Mulliken charge analysis are consistent with the traditional ranking of basicity: Cs 2 O > Cs 2 O 2 > CsO 2 .

Unveiling the Origin of Alkali Metal (Na, K, Rb, and Cs) Promotion in CO2 Dissociation over Mo2C Catalysts

“…Thus, the X–O distances were close to the sum of the X + and O 2− atomic radii, namely 2.41 Å for Na + +O 2− , 2.77 Å for K + + O 2− , 2.91 Å for Rb + + O 2− , and 3.06 for Cs + + O 2− , as also observed for the X–O distances in crystalline metal oxides, for example, 2.40 Å in Na 2 O [ 43 ], 2.79 in K 2 O [ 43 ], 2.92 in Rb 2 O [ 43 ], and 3.26 Å in CsO 2 [ 44 ]. These findings indicate that the electrostatic interaction between O and X was strong and similar to the ionic bonding between O and X in X 2 O. Wang et al found that for oxygenate species adsorbed on K + -modified Cu (111) and Cu (110) surfaces, when the distance between K and O atoms was 3.00 Å, direct bonding between O δ− and K δ+ ions occurred [ 22 ].…”

Adsorbent Materials for Carbon Dioxide Capture from Large Anthropogenic Point Sources

“…[16] Among a variety of materials reported in this category, this section describes in detail adsorption on a representative oxide, calcium oxide, along with a discussion of other important metal-based adsorbents including magnesium oxides and lithium zirconates. Although we focus attention here on calcium oxides and magnesium oxides, it should be noted that many other metal oxides display some CO 2 adsorption properties under selected conditions including lithium oxides, [98] sodium oxides, [99][100][101][102] potassium oxides, [103,104] rubidium oxides, [105] cesium oxides, [106] barium oxides, [107] iron oxides, [108][109][110][111][112] tantalum oxides, [113] copper oxides, [114,115] chromium oxides, [116][117][118][119][120] and aluminum oxides. [121][122][123][124][125][126] where M can be, for example, Mg, Ca, Sr, Ba.…”

Promotion effects of Ga2O3 on CO2 adsorption and conversion over a SiO2-supported Ni catalyst

“…There have been numerous studies focusing on the interaction of CO 2 with oxide surfaces. [4][5][6][7][8][9][10][11][12][13][14][15][16][17] Baltrusaitis et al 9 observed the formation of carbonate and bicarbonate species upon CO 2 adsorption on g-Al 2 O 3 surfaces. Rosynek identified that, for CO 2 adsorption on g-Al 2 O 3 , carbonate was the dominant surface species at high temperatures (>150 C) and low CO 2 coverages, whereas bicarbonate was formed at low temperatures (<150 C) and high CO 2 coverages.…”