CO Chemisorption Capacity Research Articles

A detailed characterization study of Ni/CeO2 catalysts identifies Ni availability as the primary factor affecting CO2 methanation performance

The structure of a catalyst has a strong impact on its performance. Here we investigate the physicochemical properties of Ni/CeO2 in an attempt to draw structure–activity relationships for CO2 methanation. A combination of characterisation methods (X-ray diffraction (XRD), 4D Scanning Transmission Electron Microscopy (4D-STEM), CO chemisorption and oxygen storage capacity study etc.) clearly demonstrates the effect of Ni crystallite size, Ni availability (i.e. catalytically accessible Ni) and oxygen vacancies at the Ni-CeO2 interface in Ni/CeO2 during CO2 methanation. Among them, the role of exposed Ni active sites is highlighted, and two possible optimisation schemes i.e. changing the support calcination temperature and the final calcination atmosphere are proposed to obtain a better dispersal of Ni NPs (nanoparticles) on CeO2. Both modification methods do not affect the reaction route, and the activity differences of Ni/CeO2 can be explained by the various hydrogenation rate of formate species, as confirmed by in situ diffuse-reflectance infrared Fourier-transform spectroscopy (DRIFTS) measurements.

Subcritical CO2 adsorption on geomaterials of coal-bearing strata in the context of geological carbon sequestration

This paper explores the adsorption behaviour of geomaterials in the framework of CO2 sequestration in shallow level coal seams. Manometric adsorption experiments were carried out on two anthracite coal samples, two rock samples from East Irish Sea, MX80-bentonite, Speswhite kaolinite, dry, wet and biofilm-laden (Bascillus mojavensis-laden) sand at subcritical pressure range (up to 6.4 MPa) of isothermal condition at 298.15 K. The experiments were aimed to investigate the influence of the biogeological conditions of coal and caprock constitutions on CO2 adsorption. At lower pressures, the moisture had an influence on the CO2 adsorption on coal resulted in reduced adsorption capacity. At elevated pressures, the volume expulsion behaviour and coal-water interaction had an influence on the adsorption capacities of moist coal sample and resulted in comparable adsorption capacities to dry sample. The disparity in the adsorption capacities between the wet powdered and wet intact core samples showed that the results obtained with powder samples may not reflect the field conditions. Wet conditions and Bascillus mojavensis bacteria influenced the adsorption capacity of sand and showed CO2 chemisorption capacity. The desorption isotherm pattern of wet and biofilm sand showed that the CO2 was continuously adsorbed independent of the gas phase pressure. Among the clay minerals, bentonite had greater affinity towards CO2. Despite the fact that the adsorption capacity of the cap rock is smaller than that of the coal samples, the experimental investigation with constituents of the cap rock provides insights into the effect of biogeological conditions of coal and rock sample constituents on CO2 storage in coal seams.

Enhanced CO2 hydrogenation to light hydrocarbons on Ni-based catalyst by DBD plasma

The high thermal stability of CO2 makes its conversion low in conventional thermal catalysis. Comparatively, non-equilibrium plasma technique provides an efficient way for CO2 hydrogenation under mild reaction conditions. Introducing effective catalysts to the dielectric barrier discharge (DBD) plasma reactor may further improve CO2 hydrogenation performance. In this way, the interaction between plasma and catalysts is important to contribute CO2 hydrogenation performance. Considering Ni-based catalyst is active for CO2 hydrogenation, we used three different kinds of carrier materials including CeO2, γ-Al2O3 and ZSM-5 as supports to prepare nickel-based catalysts by incipient impregnation in this paper. The supported Ni catalysts were tested for the plasma-induced CO2 hydrogenation to CH4 and C2+ hydrocarbons in the DBD-plasma reactor. It was found that the 15Ni/CeO2 catalyst achieved the best CO2 conversion of 85.7% and nearly 100% CH4 selectivity at 300 °C due to its high reducibility and CO2 chemisorption capacity. In addition, a significant synergistic effect was found between DBD plasma and catalyst. The performance of plasma-catalysis was considerably better than that of thermal catalysis plus pure plasma reaction, and the synergistic effects were enhanced with increase of reaction temperature. Moreover, the mechanism of the synergistic effect was proposed by analyzing the optical emission spectroscopy (OES) of DBD plasma, which provides a theoretical basis for further optimizing and application of plasma-catalysis for CO2 hydrogenation reaction.

Role of SiO2 in different iron-based catalysts for Fischer-Tropsch synthesis to light olefins

Co-precipitated FeSi-cp catalysts, impregnated FeSi-im catalyst and core–shell Fe@Si catalysts synthetized through different method were characterized by N2 adsorption, ICP, XRD, TEM, H2-TPR, CO-TPD, Mössbauer spectroscopy and TG. The configuration between Fe and Si played an important role in the catalyst performance. Both FeSi-cp and FeSi-im showed high dispersion, but easily to be agglomerated in FTS. In contrast, Fe@Si has high crystallinity and strong CO chemisorption capacity, which is conducive to the formation of Fe5C2. The SiO2 shell could isolate the active components, reduce carbon deposition and restrain the production of C5+. The results of FTS performance revealed that core–shell Fe@Si catalysts show higher C2∼4= selectivity and better FTS stability in 120 h.

Ultrathin NiZrAl layered double hydroxide nanosheets derived catalyst for enhanced CO2 methanation

It is challenging to fabricate supported Ni catalysts with more active sites to improve their low-temperature catalytic performance in CO2 methanation. Herein, firstly, ultrathin (∼4 nm) NiZrAl layered double hydroxide (LDH) nanosheets were synthesized by co-precipitation method, followed by aqueous miscible organic solvent treatment (AMOST), and applied as catalyst precursors for CO2 methanation. After H2 reduction, the surface area of Ni particles in NiZrAl-LDH-AMO-R was significantly higher than that of NiZrAl-LDH-R without AMOST. As a result, the NiZrAl-LDH-AMO-R showed higher catalytic activity than NiZrAl-LDH-R owing to its higher H2 and CO2 chemisorption capacity and lower activation energy. During the 100 h-lifetime test, NiZrAl-LDH-AMO-R maintained a steady CO2 conversion of about 92.3%. Moreover, NiZrAl-LDH-AMO-R maintained its catalytic activity after a 600 °C-hydrothermal treatment, suggesting its high stability. In situ DRIFTS results reveal that CO2 methanation on both NiZrAl-LDH-R and NiZrAl-LDH-AMO-R followed the HCOO∗ route. Interestingly, more active sites obtained after AMOST strongly promoted the generation and decomposition of HCOO∗, and thus significantly improved the activity of NiZrAl-LDH-AMO-R at low temperatures.

Synergistic effect of double solvent and accelerator on efficient synthesis of nickel phyllosilicate for CO2 methanation

In order to facilitate the synthesis of nickel phyllosilicate through the hydrothermal method, different process parameters including high or low hydrothermal temperature, single or double solvent, and with or without accelerator were investigated in this work. The Ni/DA-150-6 catalyst prepared in the presence of double solvent and the accelerator exhibited high Ni content, small Ni crystal size, and large H2 and CO2 chemisorption capacity, leading to the highest catalytic activity for CO2 methanation. Meanwhile, Ni/S-200-12 synthesized by the high-temperature (200 °C) hydrothermal method or Ni/D-150-12 prepared at 150 °C in the presence of double solvent displayed low catalytic activity owing to the low Ni content. In short, the synergistic effect of double solvent and accelerator is the most significant strategy for the efficient synthesis of Ni-phyllosilicate.

2D/2D Heterostructure of Metal-Free Ultrathin Graphdiyne/Carbon Nitride Nanosheets for Enhanced Photocatalytic Reduction of Carbon Dioxide with Water

In this study, a 2D/2D graphdiyne/carbon nitride (GD/CN) heterojunction was prepared by electrostatic self-assembly. Density functional theory calculations and physical characterization proved that the GD/CN structure was stable and exhibited strong interactions between the CN and GD. Efficient separation of photogenerated holes and electrons was realized for the GD/CN, which benefited from the efficient charge transfer facilitated by the large and tight interface. In situ X-ray photoelectron spectroscopy and energy band structure analysis verified that the photogenerated electrons generated on CN were transferred to GD under illumination. In situ diffuse reflectance Fourier transform infrared spectroscopy further confirmed the high CO2 chemisorption capacity and the conversion mechanism of the GD/CN. As a result, the CO and CH4 yields of the 2% GD/CN under ultraviolet light increased by 5.8 and 11.8 times that of pure CN with good cycle stability. This work illuminates the design and preparation of efficient and environmentally friendly photocatalysts for the robust photoreduction of CO2.

Catalytic Effect of Inherently-Water-Soluble Sodium on Zhundong Coal Gasification

Coal loaded with inherently-water-soluble sodium was prepared with dicyclohexyl-18-crown-6 to investigate the effects of inherently-water-soluble sodium on temperature-programmed isothermal gasification. The results were compared with Na2CO3-loaded coal using thermo-gravimetric analysis (TGA), and the results showed that sodium had a catalytic effect on gasification, and water-soluble sodium had a stronger catalytic ability than Na2CO3. The isothermal gasification reaction of inherently-water-soluble-sodium-loaded coal was complete in 4.68 min, whereas that of Na2CO3-loaded coal was complete in 5.39 min. Chemisorption of CO2 to chars was investigated by TGA at 300 C, which showed that the order of CO2 chemisorption capacity was similar to that of the catalytic abilities during gasification. Therefore, the CO2 chemisorption capacity accurately reflects differences in the gasification reactivity. Moreover, the distribution of sodium in coal and char structures were investigated by multiple techniques, including scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and X-ray diffraction (XRD). EDS-mapping images of Na-loaded coal indicated that inherently-water-soluble sodium mainly adhered to coal particles. This finding shows that coal graphitization was strongly inhibited by inherently-water-soluble sodium, which further strengthened the chemisorption of CO2 to char and the reactivity of char during gasification.

Lanthanum-Modified MCF-Derived Nickel Phyllosilicate Catalyst for Enhanced CO2 Methanation: A Comprehensive Study.

For the traditional preparation method, it is challenging to fabricate a supported nickel catalyst with fine size at high loading. In this work, a group of La-modified mesostructured cellular foam (MCF)-derived nickel phyllosilicates was designed and synthetized by a hydrothermal method followed by an impregnation-modification of La2O3, whose Ni contents varied from 25.3 to 32.2 wt %. Both the special property of phyllosilicate and the addition of a La2O3 modifier played significant roles in achieving high Ni dispersion and excellent catalytic performance. The formed nickel phyllosilicate was beneficial to obtain small Ni nanoparticles (<5 nm) due to its strong metal-support interaction and high specific surface area; the addition of the La2O3 modifier could further reduce the Ni particle size and decrease the reduction difficulty of the fabricated samples. On the contrary, a large Ni particle size of 13.0 nm was observed on the impregnated Ni/MCF (N/M-Im) catalyst with a Ni content of 31.7 wt %. As a result, the nickel phyllosilicate catalyst showed higher catalytic activity than the impregnated one, and the La modifier could further improve the catalytic activity especially at low temperature (<400 °C). Among all catalysts, the modified phyllosilicate catalyst N/M-P-32-5L with 180 °C-32 h-hydrothermal treatment and La2O3 content of 5 wt % was the best owing to its small-sized Ni particles, high H2 and CO2 chemisorption capacity, large turnover frequency (TOF) value, and low activation energy of 69.83 kJ mol-1. In addition, the intermediates of formate and CO were detected through in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analysis. In a 100 h-lifetime test under harsh conditions and 600 °C-steam treatment, N/M-P-32-5L showed both high sintering resistance of Ni particles and high thermal stability without the collapse of pores as well as decrease of catalytic activity, which was attributed to the special physical and chemical properties of MCF-derived nickel phyllosilicate, strong metal-support interaction over the catalyst, and the promotion of the La2O3 modifier.

Photoelectrocatalytic reduction of CO2 to methanol over CuFe2O4@PANI photocathode

The present study was aimed to convert CO2 into methanol which not only addresses the potential solution for controlling the CO2 concentration level in the atmosphere but also offers an alternative approach for the production of renewable energy source. In this perspective, a hybrid photocatalyst, PANI@CuFe2O4 was synthesized, characterized and used as a photocathode for photoelectrocatalytic (PEC) reduction of CO2 to methanol in aqueous medium at an applied potential of −0.4 V vs NHE under visible light irradiation. The combination of PANI with CuFe2O4 greatly increased the PEC CO2 reduction to methanol owing to enhance the CO2 chemisorption capacity by the photocathode surface and at the same time facilitated the separation of photogenerated electron-hole (e−/h+) pairs. The incident photon to current efficiency (IPCE) and quantum efficiency (QE) for methanol formation in PEC CO2 reduction could be achieved as 7.1 and 24.0% respectively. The rate of formation of methanol in PEC CO2 reduction was found as 49.3 μmol g−1h−1 with 73% Faradaic efficiency. Compared to photocatalytic reaction, the PEC results demonstrated that the applied potential could effectively separate the photogenerated e−/h+ pairs and therefore, enhanced the PEC CO2 reduction activity of the hybrid photocatalyst.

Pt/UiO-66 Nanocomposites as Catalysts for CO₂ Methanation Process.

Pt/UiO-66 nanocomposites with platinum target concentration of 3 wt.% were prepared by 3 preparation methods, characterized and tested in the CO₂ methanation process. Choice of the microporous UiO-66 metal-organic framework (Zr6O₄(OH)₄ with 1,4-benzene-dicarboxylate ligand) as catalytic support was motivated by the CO₂ chemisorption capacity (proven by CO₂-TPD profiles), large specific surface area (1477 m²/g) which favors a high dispersion of metal nanoparticles and good thermal stability. The preparation methods for the Pt/UiO-66 nanocomposites are: (1) wetimpregnation followed by reduction in H₂ at 200 °C for 2 h; (2) wet-impregnation followed by reduction with an aqueous solution of NaBH₄; and (3) "double-solvent" method, followed by reduction with NaBH₄. The UiO-66 based nanocomposites were characterized by N₂ adsorption-desorption (BET method), XRD, and SEM/TEM. The Pt/UiO-66 catalyst prepared by method 3 was chosen for catalytic testing due to its highest surface area, smallest platinum nanoparticles (PtNPs) size, the localization of PtNPs both on the grain's internal and external surface and best thermal stability in the desired temperature range. Its capacity to adsorb and activate CO₂ and H₂ was evaluated in thermo-programmed desorption experiments (H₂-TPD and CO₂-TPD). Hydrogen is molecularly adsorbed, while CO₂ is adsorbed both molecularly and dissociatively. The catalytic performance in the CO₂ methanation process was evaluated by Temperature Programmed Reactions (TPRea, 2 °C/min, 30-350 °C), at atmospheric pressure. The best results were obtained at 350 °C, CO₂:H₂ molar ratio of 1:5.2 and GHSV ═ 1650 h-1. In these conditions CO₂ conversion is almost 50% and CH₄ selectivity is 36%, the rest of the converted CO₂ being transformed in CO.

Enhanced CO2 capture capacity on open-cell Mg foams via humid impregnation with lithium at low temperatures

In the present work, carbon dioxide (CO2) capture capacity was evaluated after a humid impregnation process performed on the surface of open-cell magnesium (Mg) foams, with an alkaline solution of lithium hydroxide (LiOH). The Mg foams were fabricated by the infiltration casting method, using irregular particles of sodium chloride (NaCl) as space holders. Optical microscopy, helium (He) pycnometry and nitrogen (N2) adsorption-desorption techniques were used to measure the pore size, density (ρfoam) and specific surface area (As), respectively. The microstructural modifications after the impregnation process were analysed by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). Afterwards, a thermogravimetric analysis was performed to evaluate the CO2 capture capacity under different water steam (H2O) conditions. After the H2O–CO2 chemisorption process, the carbonated products were identified by the attenuated total reflexion – Fourier transform infrared spectroscopy (ATR-FTIR) technique and then, quantified through a thermal decomposition process. Thermal analysis outcomes showed that H2O–CO2 chemisorption capacity of the Mg foams considerably increased after lithium (Li) impregnation. The later as consequence of the lithium oxide (Li2O) high reactivity with CO2, and its effect on the thickening of the oxide film layer formed on the surface of the open-cell Mg foams. These results promote the possible use of this kind of cellular material as structured CO2 captor, proposing a new functional application for metallic foams and giving an alternative solution to the current environmental issues.

Transition metal oxide supported on alumina catalysts: a comparative study for the hydrogenation of octanal

Monometallic (10 wt.%) Co, Ni and Cu nanoparticles supported on alumina catalysts were prepared using an ultrasonic impregnation- cavitation method and characterized using ICP, XRD, physisorption, chemisorption and temperature programmed techniques. The copper catalyst showed higher metal dispersion and greater hydrogen and CO chemisorption capacity when compared to the nickel and cobalt catalysts. Hydrogenation of octanal carried out in a continuous flow high pressure fixed bed reactor showed that the rate of reaction and turnover number of octanol depended on the amount of hydrogen chemisorbed. The copper catalyst showed the lowest activation energy, as well as best catalytic activity. The Cu-Al catalyst which showed higher metal dispersion and low acidity, showed the highest selectivity towards octanol with no C24 acetal formation, when compared to the Ni-Al and Co-Al catalysts. Keywords: Octanal hydrogenation, octanol, copper, nickel, cobalt

On the influence of steam on the CO2 chemisorption capacity of a hydrotalcite-based adsorbent for SEWGS applications

Hydrotalcite-based adsorbents have shown great potential for use in sorption-enhanced water-gas-shift applications. A combination of thermogravimetric experiments and breakthrough experiments have been carried out to elucidate the effect of steam on the CO2 cyclic sorption capacity on a K-promoted hydrotalcite-based adsorbent. Different TGA cycles have been designed to study the mass change on sorbents exposed to different sequences of different CO2/H2O/N2 mixtures. Because the complex sorption/desorption and replacement phenomena cannot be explained by TGA experiments only, additional information from breakthrough experiments in a packed bed reactor was used to correlate the observed total mass change in the TGA cycles to the phenomena prevailing on the sorbent.A mechanism has been developed which is able to describe the cyclic working capacity, for both CO2 and H2O under different experimental conditions. It was found that at least four different adsorption sites participate in the sorption/desorption of CO2 and H2O. Two adsorption sites can be regenerated with N2, whereas the other adsorption sites require the presence of H2O or CO2 to be desorbed. Regeneration of the adsorbent with steam leads to a significant increase in the CO2 cyclic working capacity from 0.3 to 0.53mmol/g compared to a dry regeneration with N2 using the same cycle times.

Reduction of NO by CO using Pd–CeTb and Pd–CeZr catalysts supported on SiO2 and La2O3–Al2O3

The catalytic activity of Pd catalysts supported on Ce0.73Tb0.27Ox/SiO2, Ce0.6Zr0.4Ox/SiO2, Ce0.73Tb0.27Ox/La2O3–Al2O3 and Ce0.6Zr0.4Ox/La2O3–Al2O3 was studied using the reduction of NO by CO. The catalysts were characterized by X-ray fluorescence, surface area, X-ray diffraction, temperature-programmed reduction, CO chemisorption and oxygen storage capacity. Temperature-programmed reduction results indicated that Tb or Zr incorporation improves the reducibility and oxygen storage capacity. CO chemisorption data suggested the presence of large PdO particles due to the low CO/Pd ratio. No significant differences were obtained in light off temperatures (TLight off) for all Pd catalysts and the most active was 1.5%Pd/Ce0.6Zr0.4Ox/SiO2.

Thermodynamic and Kinetic Analyses of the CO2 Chemisorption Mechanism on Na2TiO3: Experimental and Theoretical Evidences

Sodium metatitanate (Na2TiO3) was successfully synthesized via a solid-state reaction. The Na2TiO3 structure and microstructure were characterized using X-ray diffraction, scanning and transmission electron microscopy, and N2 adsorption. Then, the CO2 chemisorption mechanism on Na2TiO3 was systematically analyzed to determine the influence of temperature. The CO2 chemisorption capacity of Na2TiO3 was evaluated both dynamically and isothermally, and the products were reanalyzed to elucidate the Na2TiO3–CO2 reaction mechanism. Different chemical species (Na2CO3, Na2O, and Na4Ti5O12 or Na16Ti10O28) were identified during the CO2 capture process in Na2TiO3. In addition, some CO2 chemisorption kinetic parameters were determined. The ΔH⧧ was found to be 140.9 kJ/mol, to the Na2TiO3–CO2 system, between 600 and 780 °C. Results evidenced that CO2 chemisorption on Na2TiO3 highly depends on the reaction temperature. Furthermore, the experiments were theoretically supported by different thermodynamic calculations. Th...

Analysis of the CO2 chemisorption reaction mechanism in lithium oxosilicate (Li8SiO6): a new option for high-temperature CO2 capture

Lithium oxosilicate (Li8SiO6) was successfully synthesized via a solid-state reaction. The sample's structure and microstructure were characterized using X-ray diffraction, scanning electron microscopy and N2 adsorption. The CO2 chemisorption capacity was evaluated dynamically and isothermally. Li8SiO6 was found to chemisorb CO2 over a wide temperature range with a maximum weight increase of 52.1 wt%, which corresponds to 11.8 mmol CO2 per gram ceramic. Using different thermogravimetric analyses with some structural and microstructural analyses, a CO2 chemisorption mechanism could be proposed, and the chemical species formed (Li4SiO4, Li2SiO3 and Li2CO3) during the CO2 capture process in Li8SiO6 could be elucidated. The kinetic parameter values (k) obtained for the Li8SiO6–CO2 reaction were higher than the k values previously reported for the Li4SiO4–CO2 reaction system. Additionally, ΔH‡ was found to be 53.1 kJ mol−1. According to these results, the Li8SiO6–CO2 chemisorption mechanism depends on the reaction temperature. Thus, Li8SiO6 may find potential applications as an alternative for CO2 capture because of its wide temperature range, CO2 chemisorption capacity and kinetic parameters.

Imaging Nanostructural Modifications Induced by Electronic Metal−Support Interaction Effects at Au||Cerium-Based Oxide Nanointerfaces

A variety of advanced (scanning) transmission electron microscopy experiments, carried out in aberration-corrected equipment, provide direct evidence about subtle structural changes taking place at nanometer-sized Au||ceria oxide interfaces, which agrees with the occurrence of charge transfer effects between the reduced support and supported gold nanoparticles suggested by macroscopic techniques. Tighter binding of the gold nanoparticles onto the ceria oxide support when this is reduced is revealed by the structural analysis. This structural modification is accompanied by parallel deactivation of the CO chemisorption capacity of the gold nanoparticles, which is interpreted in exact quantitative terms as due to deactivation of the gold atoms at the perimeter of the Au||cerium oxide interface.

Thermochemical and Cyclability Analyses of the CO2 Absorption Process on a Ca/Al Layered Double Hydroxide

Hydrocalumite ([Ca2Al(OH)6]2CO3·mH2O) was synthesized by precipitation and thermally activated at 300 and 550°C. Its CO2 chemisorption capacity was evaluated and compared with that of calcium oxide (CaO). Initial thermal analyses showed that CaAl-550 sample has better properties as CO2 sorbent than CaO, evaluated under similar conditions. It was determined that both materials (CaAl-550 and CaO) have similar kinetic behavior, and the presence of Ca12Al14O33 on the CaAl-550 sample did not reduce or interfere with the CO2 capture. Moreover, when the CO2 absorption-desorption cyclability was analyzed, the CaAl-550 sample apparently possessed better CO2 capture efficiency and thermal stability than CaO. In fact, different characterization analyses (nuclear magnetic resonance and scanning electron microscopy ) suggest that CO2 capture efficiency and thermal stability observed on the CaAl-550 sample can be attributed to the aluminum presence, as Ca12Al14O33.

Effect of Oxygen Addition on the Thermokinetic Properties of CO2 Chemisorption on Li2ZrO3

Lithium zirconate doped with potassium (K-Li2ZrO3) was synthesized by solid-state reaction and then its CO2 chemisorption capacity was evaluated using different CO2−O2 gas mixtures. These experiments were performed in order to evaluate the effect produced by the O2 on the kinetic parameters and on the CO2 absorption reaction mechanism. Although the CO2 capture dynamic experiments did not show significant variations as a function of the O2 content, isothermal experiments and their fitting to the Eyring’s model did. Different enthalpy activation (ΔH⧧) values were estimated for the CO2 chemisorption process, as CO2 capture is produced by two processes: Initially, the CO2 chemisorption occurs directly over the K-Li2ZrO3 surface. Then, once a Li2CO3−ZrO2 external shell is produced, CO2 chemisorption is kinetically controlled by diffusion processes, which must imply the lithium and oxygen diffusion. The ΔH⧧ values, of the CO2 direct chemisorption, increased as a function of the O2 content. It was explained in terms of a CO2−O2 competition to occupy the Li2ZrO3 surface. On the other hand, the ΔH⧧ values, of the CO2 chemisorption kinetically controlled by diffusion processes, decreased as a function of the O2 content. This result confirmed the oxygen diffusion dependency of the CO2 chemisorption on lithium zirconate.