Download or read book Population and Hierarchy of Active Species in Gold Iron Oxide Catalysts for Carbon Monoxide Oxidation written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The identity of active species in supported gold catalysts for low temperature carbon monoxide oxidation remains an unsettled debate. With large amounts of experimental evidence supporting theories of either gold nanoparticles or sub-nm gold species being active, it was recently proposed that a size-dependent activity hierarchy should exist. Here we study the diverging catalytic behaviors after heat treatment of Au/FeOx materials prepared via co-precipitation and deposition precipitation methods. After ruling out any support effects, the gold particle size distributions in different catalysts are quantitatively studied using aberration corrected scanning transmission electron microscopy (STEM). A counting protocol is developed to reveal the true particle size distribution from HAADF-STEM images, which reliably includes all the gold species present. As a result, correlation of the populations of the various gold species present with catalysis results demonstrate that a size-dependent activity hierarchy must exist in the Au/FeOx catalyst.

Download or read book Low Temperature Carbon Monoxide Oxidation Over Gold Supported on Iron Oxide Catalysts written by Chien Sze and published by . This book was released on 1995 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Springer Handbook of Advanced Catalyst Characterization written by Israel E. Wachs and published by Springer Nature. This book was released on 2023-06-12 with total page 1109 pages. Available in PDF, EPUB and Kindle. Book excerpt: Co-edited by world-renowned scientists in the field of catalysis, this book contains the cutting-edge in situ and operando spectroscopy characterization techniques operating under reaction conditions to determine a materials’ bulk, surface, and solution complex and their applications in the field of catalysis with emphasis on solid catalysts in powder form since such catalyst are relevant for industrial applications. The handbook covers from widely-used to cutting-edge techniques. The handbook is written for a broad audience of students and professionals who want to pursue the full capabilities available by the current state-of-the-art in characterization to fully understand how their catalysts really operate and guide the rational design of advanced catalysts. Individuals involved in catalysis research will be interested in this handbook because it contains a catalogue of cutting-edge methods employed in characterization of catalysts. These techniques find wide use in applications such as petroleum refining, chemical manufacture, natural gas conversion, pollution control, transportation, power generation, pharmaceuticals and food processing. fdsfds

Download or read book CO Oxidation Catalyzed by Highly Dispersed Gold on Supports written by Yalin Hao and published by . This book was released on 2008 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nanoparticles as Sustainable Environmental Remediation Agents written by Konstantinos Simeonidis and published by Royal Society of Chemistry. This book was released on 2023-10-18 with total page 317 pages. Available in PDF, EPUB and Kindle. Book excerpt: The expanding use of nanoparticles in a wide range of applications has brought to light the need to adopt an integrated approach regarding their synthesis, use, recovery and handling. This book covers the intense research field of nanoparticle utilization as remediation agents for toxic pollutants, and pays special attention to their post-application recovery, the monitoring of their fate when released, and life cycle analysis. The reader may therefore evaluate the prospects and limitations of these technologies through the prism of sustainability demands. Several chapters summarize successful applications of single or multi-phase nanoparticles for drinking water purification, wastewater and gas-stream treatment and soil consolidation. Importantly, they evaluate the potential scale-up for real-world applications that need to compete with traditional treatment methods. However, the risk of uncontrolled release into the environment can be a significant drawback to the extended use of nanoparticles. For this reason, a detailed analysis is given to aspects of their post-use recycling and regeneration, determination of release pathways, risk assessment methods and life cycle evaluation studies, highlighting the importance of preventing the unintended release of nanoparticles into the environment. This book will be a valuable resource for anyone looking at the development of nanoparticles with a view to environmental remediation strategies.

Download or read book Metal Nanocluster Chemistry written by Manzhou Zhu and published by Elsevier. This book was released on 2023-01-18 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atomically precise metal nanoclusters occupy the gap between discrete atoms and plasmonic nanomaterials, and they offer intriguing physical-chemical properties that can be rationalized in terms of their quantum size effects and discrete electronic states. The atomically precise nature of their structures lends them well to structure-property relationship elucidation, making them particularly useful for informing the rational design of nanoclusters with enhanced performance. Metal Nanocluster Chemistry: Ligand-Protected Metal Nanoclusters With Atomic Precision provides a concise introduction to the study of these useful nanoclusters. Beginning with an introduction to the fundamental concepts of, and prospects for, metal nanoclusters, the book goes on to highlight synthetic methods for controllable preparation. The subsequent chapters then highlight characterization, mechanism of size growth and structure evolution, and physical-chemical properties. Later chapters examine theoretical approaches for calculating and evaluating structures and properties. They also highlight the assembly of nanocluster building blocks and their practical applications. Drawing on the knowledge of its expert author, Metal Nanocluster Chemistry is a useful introductory guide to these exciting structures. Provides a concise introduction to atomically-precise metal nanoclusters, ranging from characterization and property investigation to applications Includes insight into both current trends and future potential, encouraging and supporting further development Holistically combines physical approaches with theoretical calculation methods

Download or read book CeO2 supported Gold Catalysts for CO Oxidation written by Veronica Illeana Aguilar-Guerrero and published by . This book was released on 2008 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Active Species Identification of Iron based Homogeneously and Heterogeneously Catalyzed Reactions written by Roland Schoch and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Precious metal based catalyst systems dominate the market for the last decades, due to their superior catalytic performance. Since economic and ecologic circumstances recently changed, a replacement of noble metals by ignoble alternatives gets inevitable. Due to its non-toxicity, availability and stable low price iron came to the fore, recently. In this work, iron-based catalysts in homogeneous cross-coupling reactions and in heterogeneous carbon monoxide oxidation were subject of investigation. In both applications - homogeneous as well as heterogeneous - multiple analytical techniques were used to get insights into the operation process of the respective catalysts. Therefore, standard techniques, like UV/Vis-, Raman- and Mößbauer spectroscopy, X-ray diffraction and specific surface area determination after BET method, were combined with X-ray absorption fine structure spectroscopy. Thereby, information about oxidation state, coordination geometry, local and electronic structure of iron could be obtained - independent on aggregation of the sample. In case of cross-coupling reaction, this information allowed the identification of the catalytically active species and the formulation of a reaction mechanism. Through synthesis of four different heterogeneous catalysts for carbon monoxide oxidation. originating from iron nanoparticles and their varying catalytic activity, structural and electronic requirements for a highly active carbon monoxide oxidation catalyst could be extracted. ; eng

Download or read book Sinter resistant Gold 144 Iron III Oxide Core shell Structures written by Michelle E. Lukosi and published by . This book was released on 2017 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the realm of catalysis, small nanoparticles have been an area of interest due to their high surface-to-volume ratio. This is even more so with gold nanoparticles in that gold only becomes catalytically active with small particles sizes. Thus, gold clusters are desirable given their uniformity, high surface-to-volume ratio, and high catalytic activity. Given the nature of small gold particles to sinter, it was found to be advantageous to protect the particles using a gold-metal oxide core-shell configuration. Core-shell heterostructures have been utilized as a catalyst that is thermally stable and exhibits a synergistic effect between core and shell, resulting in increased catalytic activity. The research contained in this document discusses the synthetic procedure of a gold-144 cluster using a variation of the Brust-Schiffrin method followed by an iron oxide coating via post-selective oxidative treatment to create a gold-144 iron oxide core-shell structure. Shell thickness is varied depending on the amount of iron precursor used and studied under the particle's catalytic efficiency with carbon monoxide oxidation. The gold- 144 iron oxide particles with Au:Fe mass ratios of 1:2, 1:4, and 1:6 were synthesized and then deposited onto silica via colloidal deposition. Using CO oxidation, each gold-144 iron oxide catalyst loaded onto silica gave varying degrees of full CO conversion depending on the thickness of the iron oxide layer. The 1:4 gold-144 iron oxide catalyst produced the best catalytic activity and was further investigated using 2-propanol conversion as well as thermal treatments using CO oxidation. Under CO oxidation, the 1:4 structure calcined at 300 degrees Celsius presented the best results, and the 1:4 ratio was still active at 100 degrees Celsius after thermal treatments. Under 2-propanol conversions, the data seems to suggest that core-shell structure provides a synergistic effect for acetone production, however, this cannot be concluded until further testing is accomplished.

Download or read book Studies of Model Systems for the Low Temperatureoxidation of CO Bysupported Gold Catalysts written by Simon Braun and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The preparation and reactivity of a range of model systems for the low temperature oxidation of CO by gold catalysts have been investigated with a view to assessing their feasibility for bridging the 'materials gap' between well-defined single crystalline models and practical supported catalysts. The studied systems included gold powder, electrochemically oxidized gold foil, gold nanoparticles prepared on Ti02 single crystal surfaces by spin-coating and gold nanoparticles prepared on Ti02 powder by deposition-precipitation. Particular attention was paid to the reduction of oxidised gold species, since these are the common precursors in the preparation of practical nanoparticular catalysts. Oxidised gold species may also be mechanistically relevant for the catalytic low-temperature CO oxidation. A low volume reactor was designed for studies of flat gold model catalysts. It was tested with in situ X-ray absorption spectroscopy (XAS). The design of the reactor cell allows the use of further techniques including UVNis spectroscopy, X-ray differaction (XRD), Raman scattering and Infrared (IR) Spectroscopy. The reactor was also designed to permit reaction rate measurements with a mass spectrometer. In comparison to other reactors reported in the literature, this design is very cost efficient, not only in its construction but also due to its compatibility with a wide range of spectroscopic techniques. In situ X-ray photoelectron spectroscopy (XPS) on gold particles supported on Ti02 powder indicated that different atmosphere could change the morphology of the gold particles. This change is more prominent for smaller particles. The formation of graphite like spices under a CO atmosphere was observed as well. X-ray photoelectron spectroscopy (XPS) and in situ Au L-edge XAS indicated that suitable gold nanoparticles could be prepared by spin coating of tetrachloroaurlc acid solutions onto rutile single crystals. Gold loadings as low as 0.1 and 0.03 monolayers could be achieved. The XAS data indicated the presence of low average Au-Au coordination numbers, suggesting the presence of very small nanoparticles. XA spectra taken under CO and O2atmosphere indicated that CO interacts with the gold particles. In situ X-ray absorption near edge structure (XANES) C K-edge studies were carried out on electrochemically oxidised gold foils. When exposed to carbon monoxide at pressures up to 10-2 mbar the anodic oxide layers reduce rapidly. This process is accompanied by the formation of a carbonaceous layer at the surface. XPS studies revealed that the foils were superficially not fully reduced. Au Lm-edge spectra showed that the reduction of the samples proceeds also in oxygen at elevated temperatures, with an ultrathin oxidic layer remaining near the surface, similar to the samples treated with CO at 10-2 mbar pressure. The-catalytic.actiyity-ofuIlsllPported bulk gold, in form of gold powder with particle sizes between 0.5 ~m and 2 ~m, was determined. Pure gold was found to be generally active at temperatures above 570 K. Heating to 700 K in a 1:1 COI02 mixture resulted in a conditioning --effect, -leading to-higher catalytic activity of the gold powder. An activation energy of 53 kJ/mol for the CO oxidation reaction was determined from the temperature dependence of the reaction. Scanning electron microscopy and atomic force microscopy images revealed mesoscopic surface morphology changes caused by the catalytic, which seems to be associated with the conditioning of the catalyst.

Download or read book One dimensional 1 D Nanostructured Metal Oxides for Catalytic Oxidation of Hydrocarbons written by Yunzhe Feng and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Catalytic oxidation of hydrocarbons has been intensively studied, with the purpose of minimizing emissions of pollutants and facilitating the combustion process. Noble metals, such as platinum and palladium, are the most effective catalysts for the oxidation of hydrocarbons. However, the limited supply of these noble metals imposes a need for developing alternative catalysts. Transition metal oxides are attractive alternatives due to their high thermal stability and low cost. Previous studies of metal oxide catalysts have focused on metal oxide nanoparticles (NPs) supported on porous substrates, such as Al2O3, ZrO2 and spinel-type (AB2O4) supports. Although the dispersed metal species over large surface area have shown much higher activity than the bulk metal oxide, there are several limitations. First, interactions between the support and NPs at high temperatures impede the fundamental understanding of the catalytic properties of individual NPs, and limit their application conditions. Moreover, the solid supports limit the loading of NPs because NPs tend to aggregate at large loadings, leading to a decrease in catalytic activity. Herein, one-dimensional (1-D) nanostructured metal oxide were directly grown on metal mesh substrates and used as catalysts for hydrocarbons oxidation. The 1-D nanostructured catalysts benefits from reduced interaction with the substrates, great flexibility in increasing the catalyst loading, and convenience in tuning the surface chemistry for higher catalytic activity, thus exhibit comparable or better catalytic activity and stability compared to the supported NPs. As one of the most active metal oxide catalysts, CuO was used as a model system to demonstrate the effectiveness of the 1-D nanostructured metal oxide catalysts. CuO NWs have been grown on Cu mesh by solid phase diffusion and applied to catalyze methane oxidation reactions. The CuO NWs have shown comparable or even better activity and stability than the supported CuO NPs. Moreover, owing to the fact that the NWs were exposed on the substrate surface and easy to access, two methods were used to tune the NWs for enhanced catalytic activity. The first one was to reduce the CuO NWs to more active Cu2O NWs by H2 plasma, which has shown 20% increase activity for CH4 oxidation reactions and several times higher activity for CO oxidation reactions. The kinetics study have shown that the bulk oxygen diffusion in Cu2O was faster, which could be one of the reasons for higher activity of Cu2O than that of CuO. The second tuning method was to decorate the CuO NWs with more active NP materials, such as Co3O4 and noble metals with a newly developed simple, fast and general sol-flame method. After the Co3O4 decoration, the CuO NWs surface was uniformly and densely covered by Co3O4 NP-chain structures, with large NP loading, high surface area and minimal aggregation, resulting in times higher activity in catalyzing CH4 oxidation. Moreover, this sol-flame method is a general method to decorate NWs with various NPs, and even to dope NWs with dopants for desirable properties. Given the generality and simplicity of the sol-flame methods, it can be applied to not only catalysis, but also other important application areas, such as lithium ion battery, supercapacitor and photoelectrochemical devices. In addition, to incorporate Cu and Co, the most active metal oxide catalyst Co3O4 was grown as 1-D structure on stainless steel mesh with the Cu2+ ion enhanced ammonia-evaporation-induced synthesis method. The synergetic effects of Cu and Co in catalytic process were studied, which have shown that the Cu2+ improved the nucleation and growth process of 1-D Co3O4, however, the catalytic activity is mainly from the Co species.

Download or read book Novel Photodeposited Catalysts for Carbon Monoxide Oxidation and Preferential Oxidation of Carbon Monoxide in the Presence of Hydrogen PROX written by Sze Chi Chan and published by ProQuest. This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: It has been shown that gold nanoparticles supported on metal oxides with sizes below 5 nm exhibit unique catalytic properties for CO oxidation, water-gas shift, and epoxidation of propylene. In particular, Au/TiO 2 exhibits CO oxidation activity at temperature as low as 90 K. Recent research reported that silver nanoparticles supported on TiO 2 are similar to Au nanoparticles supported on TiO 2 . Conventional methods for preparing Ag/TiO 2 and Au/TiO 2 supported catalysts include deposition-precipitation, wet impregnation and co-precipitation. Among these methods deposition-precipitation has shown the best results for these reactions due to the narrow size distribution of Ag and Au. The major disadvantage of the deposition-precipitation method is that Au and Ag particle sizes are very sensitive to precursor concentration. Preparation of Au particles less than 5 nm requires a low precursor concentration and low Au loading. In this work, a different approach, photodeposition, was used to prepare Ag and Au nanoparticles supported on TiO 2 . The main shortcoming of photodeposition is that its efficiency is very sensitive to both bulk and surface structural features. However, such problems can be overcome by reducing the size of TiO 2 particles to the nanoscale. Photodeposition of Ag nanoparticles on commercial TiO 2 particles and nanoparticles was performed on microscope grid-supported samples in order to provide direct visualization of the spatial distribution of photoactive sites on sub-micron-scale and nanoscale TiO 2 particle surfaces and to create materials for potential catalytic applications. HRTEM (high-resolution transmission electron microscopy) and HAADF-STEM (high-angle annular dark-field scanning transmission electron microscopy) were used to characterize these materials. The size and spatial distributions of the Ag nanoparticles on the commercial TiO 2 were not uniform; the concentration of Ag was higher on grain boundaries and at the edges of these submicrometer particles. In the case of TiO 2 nanoparticles, the size distribution of the Ag nanoparticles deposited was relatively uniform and independent of irradiation time and photon energy. The amount of Ag deposited on TiO 2 nanoparticles was at least 6 times higher than that on commercial samples for comparable irradiation conditions. Compared to the case of Ag photodeposition, the difference in the amount of Au photodeposited on TiO 2 particles and nanoparticles was even greater, especially at low precursor concentration. Photodeposition on TiO 2 nanoparticles is suggested as a potential method for the preparation of Ag/TiO 2 and Au/TiO 2 catalysts. The high photoreactivity of TiO 2 nanoparticles makes them an ideal material for preparation of supported metal catalysts when highly uniform nanoscale particle size is required. Extending the previous work, the Ag and Au photodeposition on TiO 2 nanoparticles were scaled-up from micro scale to laboratory scale to generate sample powders in sufficient quantity to be utilized in catalytic reactor. Most of the methods published for the preparation of metal-decorated TiO 2 by photodeposition involve suspended particles in a aqueous media. Our approach for the scale-up process was different, and was developed based on the sample preparation for metal photodeposition on microscope grids. A thin film of TiO 2 nanoparticle powders coated on a glass plate was obtained by using a spin-coating technique before metal photodeposition. Several commercial TiO 2 nanoparticles were used in this study, in order to choose appropriate samples for the scale-up experiments. Preliminary studies of the photoreactivity of commercial TiO 2 nanoparticles for Ag photodeposition on a microscope grid were carried out prior to the scale-up process. The effects of Ag photoreduction conditions, in particular the radiation source and the metal precursor solution concentration, on Ag photodeposition were investigated to determine the optimum conditions for the scale-up process. The size and spatial distribution of Ag nanoparticles, as well as the Ag loading on commercial TiO 2 nanoparticles for the scale up process under various conditions were determined using TEM and HAADF-STEM techniques. After the optimal conditions for the scale-up process were established, Ag/TiO 2 and Au/TiO 2 nanoparticles obtained from the scaled-up process were characterized by atomic absorption spectroscopy (AAS), X-ray diffraction (XRD), Xray photoelectron spectroscopy (XPS) and HAADF. In addition, Ag/TiO 2 and Au/TiO 2 nanoparticles were also prepared using traditional deposition-precipitation methods. The catalytic performance of Ag/TiO 2 and Au/TiO 2 nanoparticles prepared using two different methods for CO oxidation and preferential oxidation of CO in the presence of H 2 (PROX) were investigated using a high-throughput reactor. Results obtained from this study showed that the size of Ag particles, Ag loading, as well as preparation method contributed to the difference in activity of Ag/TiO 2 for CO oxidation and PROX. In the case of Au/TiO 2 the difference in activity for CO oxidation and PROX is mainly due to the preparation method and Au loading.

Download or read book Study of Heterogeneous Gold and Gold Alloy Catalysts Via Analytical Electron Microscopy written by Qian He and published by . This book was released on 2013 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: A statistically relevant population analysis of the various Au species present in a series of co-precipitated Au/FeOx catalysts has been carried out in order to identify/conrm the most active Au species for low temperature CO oxidation. By comparing the relative populations of Au species with different sizes, we show that the 1-5 nm nanoparticles are not primarily responsible for high catalytic activities. Instead, we propose that sub-nm Au clusters are the dominant active species and describe how the evolution of these sub-nm clusters during the heat treatment step is crucial in determining the catalytic performance of the catalysts.

Download or read book Carbon Monoxide Oxidation Over Three Different Oxidation States of Copper written by Glenn Geoffrey Jernigan and published by . This book was released on 1994 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis of Active Supported Gold Catalysts for CO Oxidation and Light Alkane Activation written by Saleh Abdullah Al-Sayari and published by . This book was released on 2006 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Use of Heterogenous Gold Catalysts in Wildfire Gas Mask Application CO and Formaldehyde Oxidation Comparative Study written by and published by . This book was released on with total page 1 pages. Available in PDF, EPUB and Kindle. Book excerpt: Catalysts consisting of gold nano-particles supported on metal oxide carriers (Al2O3, TiO2, FeOX, ect) have been shown to be higly active for carbon monoxide (CO) oxidation under varying environmental conditions. Au catalysts are highly efficient at oxidising toxic CO (35-50 ppm TWA) to CO2. [partial abstract].

Download or read book Unveiling the Structure and Reactivity of Rare Earth Oxides and Gold Catalysts Through Density Functional Theory written by Shikun Li and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the field of heterogeneous catalysis and electrocatalysis, rare earth oxides (REOs) are increasingly gaining attention as a relatively unexplored group of materials, while nanoscale gold catalysts have demonstrated significant potential in low-temperature applications. These two kinds of catalyst systems can not only act as the active components for the catalysis reactions separately, but can also be combined into one metal-oxide hybridized system. Considering the complexity of mixed metal-oxide systems, it is essential to first study the surface properties and reactivity of individual components, such as rare earth oxides and nanostructured gold. Density functional theory (DFT) enables the modelling of REOs and gold, and provides a deeper microscopic understanding of their catalytic properties. However, a reliable and universal computational approach is required for modelling their properties, particularly REOs due to the strong correlation of the f-orbital electrons and the lack of systematic studies. Therefore, the first step of this work was to systematically assess the performance of the currently-available methods, here applying PBE+U and HSE06 in describing the structural parameters and energetic properties of the selected hexagonal lanthanide sesquioxides and the cubic fluorite-type cerium dioxide. Several representative surfaces were constructed to evaluate the transferability of the obtained optimal parameter U for bulk REOs to simulate surface properties, such as the electronic structure and adsorption properties, comparing the PBE+U level to the hybrid HSE06 level. After determining the optimal method for describing bulk REOs and surfaces, we further selected the La2O3(0001) surface to investigate the influence of the selected s-block, d-block and f-block heteroatoms on the surface Lewis acidity/basicity and surface reducibility through replacing the surface La atom by the dopants. Finally, we focused on the gold catalysts and elucidated the possibility of self-organized oxygen species formed on the selected Au(221) surface, followed by the investigation of the reactivity for CO and O2 on the surface. The main results of our work can be summarized as follows. The HSE06 hybrid functional has been found to accurately reproduce lattice parameters and certain energetic properties compared to experimental values. The PBE+U method can only reproduce the results of HSE06 or experimental values if the U parameter is selected from an appropriate range of values. Typically, the U parameter values must be adjusted for different Ln2O3 (denoting lanthanide sesquioxides) or CeO2 to accurately describe different properties. Most bulk oxide structural parameters and reaction energies can be accurately described by PBE+U with a relatively small U parameter. However, a larger U value is needed to simulate surface electronic properties of Ln2O3 or CeO2, such as 4f electron localization. For the La2O3(0001) surface, a distinct linear relationship was found between the surface reducibility, as measured by oxygen vacancy formation energy and the band center of the unoccupied La5d states or the occupied O2p states of the surface La or O atoms. It was noted that the formation of an oxygen vacancy shifts the La5d and O2p band centers downwards with respect to the Fermi level, which can be offset to various degrees by low-valence s-block and d-block dopants (Cu or Ni), but not so much by the high-valence d-block dopants and f-block dopants chemically similar to La atoms. The d- or p-band center relative to the Fermi level is more indicative of the surface reducibility, compared to the Lewis acidity/basicity measured by adsorption energies of molecules with Lewis basic/acidic properties. The Lewis acidity of the surface La atoms does not change significantly upon doping, yet the Lewis basicity of O atoms varies slightly. In a study of the role of self-organized surface oxygen structures for gold catalysts, we constructed a double oxygen (O) chain along the step edge on the Au(221) surface, with or without oxygen vacancies that may form on gold-based catalysts under practical catalytic conditions. Accompanied by an increased adsorption strength of CO and O2 on the oxygen chain with vacancies, CO and O2 also become more activated. The dissociation of O2 has a factor of two lower activation energy compared to the regular Au(221) surface. We considered two types of mechanisms for CO oxidation: dissociative and associative. Both mechanisms may compete on the O chain with two adjacent vacancies depending on the given thermodynamic conditions when CO and O2 co-adsorb on the chain or the step edge on the Au(221) surface. A more favorable pathway can be found with the initial co-adsorption state of CO* at a terrace site and O2* adsorbed at a vacancy site.