CO Oxidation Pathways Research Articles

Impact of Fe2(MoO4)3 and ZnMoO4 on CO Tolerance of Pt/C catalysts for enhanced methanol electrooxidation efficiency

Success of Pt/C catalyst in electrooxidation of methanol is highly influenced by its ability to withstand the poisoning effects of carbonaceous species adsorbed on the catalytic surface. Covalently bonded CO molecules occlude the active sites of the catalytic surface, impeding methanol adsorption. In this study, Pt/C-based nanocomposite catalysts were synthesized incorporating Fe2(MoO4)3 and ZnMoO4 to form heterojunctions through intermittent microwave-assisted polyol method to augment the CO oxidation pathway by introducing hydroxy groups adsorbed on their surfaces. Thorough characterization of the catalysts elucidated their chemical and phase purity, bonding configurations, and oxidation states, with various electroanalytical techniques employed to probe the mechanism of activity enhancement. Furthermore, the distinctive electron density profiles of these molybdate species have been identified as potential facilitators of methanol adsorption on the platinum surface. Equimolar composition in formulating the composite catalysts yielded a fivefold increase in catalytic activity (with ZnMoO4) and a 1.5-fold increase (with Fe2(MoO4)3). This approach demonstrates promise for tailoring Pt/C catalysts to develop industrially viable CO-tolerant and highly stable electrocatalysts.

Graphene/MoS2-assisted alum sludge electrode induces selective oxidation for organophosphorus pesticides degradation: Co-oxidation and detoxification mechanism

Designing an electrode that can generate abundant free radicals and 1O2, which can effectively degrade and detoxify organophosphorus pesticides (OPPs) through a co-oxidation pathway, is important. In this study, we prepared a electrode GO/MoS2@AS by supporting MoS2 on alum sludge (AS) under graphene oxide (GO) nanoconfinement. The results show that the dominant role of 1O2 at the cathode and •OHads at the anode for degradation, in addition to the involvement of 1O2 in the cathodic degradation mechanism, can be attributed to the abundant precursor •O2– and H2O2. Furthermore, calculations using density functional theory and toxicity prediction of products show that the energy (∆E) requirements of •OHfree to break the C–O bond of the pyridine ring and phosphate group are higher than that required for 1O2, and this non-radical oxidation plays a key role in detoxification. In contrast, accelerating ring opening and oxidation processes are attributed to radical oxidation. Above all, the cathodic detoxification is more effective than anodic detoxification. Three prevalent OPPs, chlorpyrifos, glyphosate, and trichlorfon, were degraded in the GO/MoS2@AS system by over 90 %, with mineralization rates of 76.66 %, 85.46 %, and 82.18 %, respectively. This study provides insights into the co-oxidation degradation and detoxification mechanism mediated by 1O2 and •OHfree.

Mechanistic insight into the catalytic CO oxidation and SO2 resistance over Mo-decorated Pt/TiO2 catalyst: The essential role of Mo

The problem of CO oxidation in incomplete combustion from steel industry is that the deactivation of Pt-based catalysts by SO2. Here, we have elaborately designed a series of Mo-decorated 0.1 wt.% Pt/TiO2 catalyst (Pt/Mo/Ti) catalyst. The catalytic test showed that the Pt/3Mo/Ti catalyst achieved 100 % CO conversion above 200 °C and maintained excellent long-term catalytic stability in the presence of SO2. The enhancement in SO2-tolerance ability was due to the suitable Brønsted acidity to weaken the SO2 adsorption and strong charge transfer ability to reduce the oxidation of SO2 to SO3. Aberration-corrected scanning transmission electron microscopy (STEM) suggests that the Pt-O-Mo species are present in atomically dispersed form in the Pt/3Mo/Ti catalyst. The surface O = MoO4 sites with terminal Mo = O bond prevented SO2 from reacting with platinum, thus inhibiting its migration to TiO2 and TiOSO4 formation. We also revealed the strong interaction between platinum and molybdenum and characterized the CO oxidation pathway in the presence of SO2. This research offers new insights into the mechanism of the catalytic CO oxidation and SO2 resistance over Mo-decorated Pt/TiO2 catalyst.

Interrogating site dependent kinetics over SiO2-supported Pt nanoparticles

A detailed knowledge of reaction kinetics is key to the development of new more efficient heterogeneous catalytic processes. However, the ability to resolve site dependent kinetics has been largely limited to surface science experiments on model systems. Herein, we can bypass the pressure, materials, and temperature gaps, resolving and quantifying two distinct pathways for CO oxidation over SiO2-supported 2 nm Pt nanoparticles using transient pressure pulse experiments. We find that the pathway distribution directly correlates with the distribution of well-coordinated (e.g., terrace) and under-coordinated (e.g., edge, vertex) CO adsorption sites on the 2 nm Pt nanoparticles as measured by in situ DRIFTS. We conclude that well-coordinated sites follow classic Langmuir-Hinshelwood kinetics, but under-coordinated sites follow non-standard kinetics with CO oxidation being barrierless but conversely also slow. This fundamental method of kinetic site deconvolution is broadly applicable to other catalytic systems, affording bridging of the complexity gap in heterogeneous catalysis.

Changes in soil microbial functions involved in the carbon cycle response to conventional and biodegradable microplastics

Biodegradable mulch film has become an encouraging alternative to conventional petroleum–based plastic, but it is likely to generate more microplastics (MPs) than conventional films with lower resistance and thus profoundly affects the soil environment. However, the effects of biodegradable (BMPs) and conventional polyethylene MPs (PE–MPs) on soil microbial carbon (C) cycle remain unclear. Here, metagenomic sequencing was used to investigate microbial functional and relative taxonomic traits in response to PE–MP and BMP addition (5 % w/w) via a soil microcosm experiment. The results showed that the presence of BMPs, rather than PE–MPs, significantly changed soil microbial C cycling patterns at the functional and taxonomic levels. In soils, BMP addition significantly increased the abundances of genes regulating aerobic respiration, C decomposition (intracellular), C fixation, fermentation and CO oxidation pathways compared to those in the control and PE–MP added soils. Specifically, BMPs promoted soil starch and PHA (liable C) degradation, acetate and ethanol fermentation, Calvin–Benson–Bassham (CBB) cycle and 3–hydroxypropionate/4–hydroxybutyrate (3HP/4HB) associated with C fixation. Most of these C cycling pathways were further strengthened in the microplastisphere of BMPs. Furthermore, MPs selectively enriched specific taxa on their surface and subsequently increased their abundance in soils; Bradyrhizobium, Ramlibacter and Variovorax (enriched by BMPs) positively regulated labile C degradation, and Amycolatopsis and Nocardia (enriched by PE–MPs) promoted recalcitrant C degradation. Moreover, Pseudonocardia and Variovorax that were enriched by BMPs improved C dissimilation and assimilation by regulating fermentation and C fixation processes, respectively. Taken together, these results improve the understanding of the influence of conventional and biodegradable MPs on soil C cycling pathways and related microbial communities, highlighting that the presence of BMPs rather than PE–MPs accelerates soil C turnover.

Exploring the role of oxygen species on β- and γ-MnO2 catalyst under in-plasma catalysis configuration at different temperature in CO oxidation using operando TPR-DRIFTS-MS

Catalyst surface active oxygen species have an important influence on plasma catalytic oxidation. However, the reaction process of CO and O3 migration and transformation on the catalyst surface during discharge at different temperature is still unclear. In this study, β- and γ-MnO2 are selected to unveil the roles of different oxygen species under in-plasma catalysis configuration at different temperature in CO oxidation. Operando TPR-DRIFTS-MS is used to reveal CO and O3 oxidation pathways. The results show that O3 can react with CO at room temperature, and O3 is also converted to other reactive oxygen species on the catalyst surface. As the temperature increases, the oxygen species of the catalyst itself (MnO and Mn-O-Mn) can react with CO to form oxygen vacancies (Mn-□-Mn and Mn=□). Mn-□-Mn are beneficial for O2 decomposition and promotes the regeneration of MnO and Mn-O-Mn. The carbonate covered on the surface of the catalyst is the rate-determining step of CO oxidation. It is hoped that Mn-based catalysts with more reactive oxygen species and oxygen defects will be prepared to facilitate low-temperature CO oxidation under plasma conditions.

Directing the persulfate activation reaction pathway by control of Fe-Nx/C single-atom catalyst coordination

In the reaction systems involving peroxymonosulfate (PMS) activation, the degradation of organic pollutants is influenced by the distinct roles played by the oxidation of free radicals and non-free radicals. The synergistic effect resulting from both oxidation pathways is often more efficient compared to a single oxidation pathway, as it allows for the optimal utilization of oxidation capacity and adaptation to complex reaction environments. Nitrogen-doped carbon substrates hosting single-atom catalysts (SACs) are anticipated to serve as an optimal platform for managing the dual oxidation pathways in the PMS activation reaction. This is attributed to the availability of numerous reaction sites that meet the activation requirements. However, there's a lack of substantial reports on this subject. Herein, we synthesized a series of single-atoms Fe nitrogen-doped carbon catalysts with different coordination structures by adjusting the coordination numbers between Fe and N atoms. It is used to investigate the reaction pattern of PMS over SACs, so as to enhance the catalytic efficacy of SACs through distinct coordination structures. The experimental and theoretical results indicate that PMS functions as both an electron receiver and provider on FeNx/C catalysts. Moreover, the specific arrangement of the Fe-N-C structure influences the exchange of electrons between the catalysts and PMS. Hence, the co-oxidation pathway of free radicals (OH, SO4− and O2−) and non-free radicals (1O2) can be modulated by altering the coordination number of Fe and N atoms during PMS activation. The elimination efficiency of tetracycline hydrochloride was significantly enhanced due to the abundance of both free radical and non-free radical species generated in the FeN3/C/PMS reaction system, exhibiting a degradation kinetic constant of 0.564 min−1. In addition, it showed promising potential for application in practical wastewater degradation, exhibiting high anti-interference to general environmental disturbances (such as humic acid, chloride ions, bicarbonate ions and nitrate ions).

Theoretical Study of the Reactive Mechanisms of Li-Doped Ni-Based Oxygen Carrier during Chemical Looping Combustion.

Ni-based oxygen carriers (OCs) are considered promising materials in the chemical looping combustion (CLC) process. However, the reactivity of Ni-based OCs still offers the potential for further enhancement. In this work, the Li doping method has been employed for the modification of Ni-based OCs. The reactivity and microreaction mechanisms of different concentrations of Li-doped Ni-based OCs with CO in CLC are clarified using density functional theory (DFT) simulation. The structures, energy, and density of states are obtained through computational investigation of the reaction path in elementary reactions. The results show that (1) the adsorption energies of CO molecules on NiO surfaces with 4, 8, and 12% Li doping concentrations are -0.53, -0.48, and -0.54 eV, respectively, demonstrating an enhanced reactivity compared to that of pure NiO (-0.41 eV); (2) the calculation of the transition state indicates that the most favorable pathway for CO oxidation takes place on the surface of NiO with an 8% Li doping concentration, exhibiting the lowest energy barrier of 0.51 eV; and (3) the oxygen vacancy formation energies on the surface of NiO are 3.05, 2.30, and 2.10 eV for 4, 8, and 12% doping concentrations, respectively. Additionally, the decrease in oxygen vacancy formation energies exhibits a gradual decline with an increasing Li doping concentration. By comprehensive analysis, 8% is considered to be the optimal doping concentration of NiO for chemical looping combustion.

Tuning interaction strength between CeO2 and iridium to promote CO oxidation over Ir/TiO2

The interaction between support and noble metal plays a crucial role in heterogeneous catalysis design. However, how to tune metal support interactions to optimize the activity still needs further exploration. CeO2 was introduced to promote CO oxidation over Ir/TiO2 by adjusting the interaction strength between iridium (Ir) and CeO2. The strong interaction between Ir and CeO2 blocks CO adsorption and causes low CO oxidation activity. However, introducing CeO2 on Ir/TiO2 produces localized interaction between Ir and CeO2, which can tune the surface electronic state of Ir, so a “volcano curve” relationship between CO oxidation activity and electronic state is built. Limited amount of CeO2 on Ir/TiO2 (Ir/Ce0.2Ti) leads to CO complete oxidization at 22 °C, and a new pathway for CO oxidation was explored. The study demonstrates that the utilization of tuning interaction strength between active metal and support is a potential method to increase the catalytic activity.

Termolecular Eley–Rideal pathway for efficient CO oxidation on phosphorene‐supported single‐atom cobalt catalyst

AbstractDensity functional theory calculations are conducted to examine the oxidation of CO on a single Co atom anchored on a two‐dimensional phosphorene monolayer (Co@Pn). The stability of the Co adatom on the Pn monolayer was revealed by ab initio molecular dynamics simulations. Three plausible pathways for CO oxidation over Co@Pn were explored: Langmuir–Hinshelwood (LH), Eley–Rideal (ER), and the recently proposed termolecular Eley–Rideal (TER) mechanisms. The TER pathway has a relatively lower energy barrier for the rate‐determining step (0.55) than those of the LH (0.81) and ER (0.70 eV) pathways. The efficiency of TER pathway can be interpreted by CO‐promoted O2 activation via the effective formation of a five‐membered ring composed of two CO and one O2 molecules. The results open a new avenue for developing phosphorene‐supported non‐noble transition metal single‐atom catalysts for various catalytic applications.

Coadsorption Interfered CO Oxidation over Atomically Dispersed Au on h-BN.

Similar to the metal centers in biocatalysis and homogeneous catalysis, the metal species in single atom catalysts (SACs) are charged, atomically dispersed and stabilized by support and substrate. The reaction condition dependent catalytic performance of SACs has long been realized, but seldom investigated before. We investigated CO oxidation pathways over SACs in reaction conditions using atomically dispersed Au on h-BN (AuBN) as a model with extensive first-principles-based calculations. We demonstrated that the adsorption of reactants, namely CO, O2 and CO2, and their coadsorption with reaction species on AuBN would be condition dependent, leading to various reaction species with different reactivity and impact the CO conversion. Specifically, the revised Langmuir–Hinshelwood pathway with the CO-mediated activation of O2 and dissociation of cyclic peroxide intermediate followed by the Eley–Rideal type reduction is dominant at high temperatures, while the coadsorbed CO-mediated dissociation of peroxide intermediate becomes plausible at low temperatures and high CO partial pressures. Carbonate species would also form in existence of CO2, react with coadsorbed CO and benefit the conversion. The findings highlight the origin of the condition-dependent CO oxidation performance of SACs in detailed conditions and may help to rationalize the current understanding of the superior catalytic performance of SACs.

Interaction mechanism between CO and H2S over CuFe2O4 oxygen carrier during chemical-looping combustion: A DFT study

During the chemical-looping combustion process, CO as an important part of syngas and H2S as a common sulfur compound inevitably coexist in the fuel. Based on the density functional theory and periodic structure model, the interaction mechanism between CO and H2S over the O-defective CuFe2O4 surface was comprehensively investigated. The results show that the adsorption energies of adsorbates on the O-defective surface are in the order of S* (−205.42 kJ/mol) > HS* (−191.37 kJ/mol) > CO (−44.88 kJ/mol) > H2S* (−28.97 kJ/mol). CO adsorption over the O-defective surface is dominant as compared to H2S adsorption. The adsorption energies of CO in the presence of H2S, HS* and S* are − 73.21, −255.98 and − 105.35 kJ/mol, respectively. The adsorption strength of CO over the O-defective surface was enhanced in the presence of HS* or S*. The presence of CO* will greatly limit the H2S dehydrogenation process, especially for the second dehydrogenation step. The energy barriers of CO oxidation with the participation of H2S*, HS* and S* are 69.66, 51.42 and 14.19 kJ/mol, respectively. COS may be produced form the reaction between CO and S* with an energy barrier of 27.13 kJ/mol, following the Eley–Rideal reaction mechanism. CuFe2O4 oxygen carrier exhibits good anti-sulfur ability because the reaction of CuFe2O4 with CO and H2S kinetically prefers the CO oxidation pathway rather than the COS formation pathway.

Self-replicating Biophotoelectrochemistry System for Sustainable CO Methanation.

Efficient conversion of CO-rich gas to methane (CH4) provides an effective energy solution by taking advantage of existing natural gas infrastructures. However, traditional chemical and biological conversions face different challenges. Herein, an innovative biophotoelectrochemistry (BPEC) system using Methanosarcina barkeri-CdS as a biohybrid catalyst was successfully employed for CO methanation. Compared with CO2-fed BPEC, BPEC-CO significantly extended the CH4 producing time by 1.7-fold and exhibited a higher CH4 yield by 9.5-fold under light irradiation. This superior conversion of CO resulted from the fact that CO could serve as an effective quencher of reactive species along with the photoelectron production. In addition, CO was used as a carbon source either directly or indirectly via the produced CO2 for M. barkeri. Such a process improved the redox activities of membrane-bound proteins for BPEC methanogenesis. These results were consistent with the transcriptomic analyses, in which the genes for the putative CO oxidation and CO2 reduction pathways in M. barkeri were highly expressed, while the gene expression for reactive oxygen species detoxification remained relatively stable under light irradiation. This study has provided the first proof-of-concept evidence for sustainable CO methanation under a mild condition in the self-replicating BPEC system.

Interspersing CeOx Clusters to the Pt-TiO2 Interfaces for Catalytic Promotion of TiO2-Supported Pt Nanoparticles.

We propose an interface-engineered oxide-supported Pt nanoparticle-based catalyst with improved low-temperature activity toward CO oxidation. By wet-impregnating 1 wt % Ce on TiO2, we synthesized hybrid oxide support of CeOx-TiO2, in which dense CeOx clusters formed on the surface of TiO2. Then, the Pt/CeOx-TiO2 catalyst was synthesized by impregnating 2 wt % Pt on the CeOx-TiO2 supporting oxide. Pt-CeOx-TiO2 triphase interfaces were eventually formed upon impregnation of Pt on CeOx-TiO2. The Pt-CeOx-TiO2 interfaces open up the interface-mediated Mars-van Krevelen CO oxidation pathway, thus providing additional interfacial reaction sites for CO oxidation. Consequently, the specific reaction rate of Pt/CeOx-TiO2 for CO oxidation was increased by 3.2 times compared with that of Pt/TiO2 at 140 °C. Our results demonstrate a widely applicable and straightforward method of catalytic activation of the interfaces between metal nanoparticles and supporting oxides, which enabled fine-tuning of the catalytic performance of oxide-supported metal nanoparticle classes of heterogeneous catalysts.

Titania-Carbon Nitride Interfaces in Gold-Catalyzed CO Oxidation.

Gold-catalyzed CO oxidation is a reaction of both practical and fundamental interest. In particular, rate-determining oxygen activation pathways have attracted a lot of attention. They have been found to depend on the surface chemistry of the catalyst support, titania providing the most active catalysts and carbon nitride leading to inactive catalysts. Here, we show that C3N4-TiO2 composites with rather similar surface chemistries can be engineered by using titania nanotubes as hard templates and by performing the polycondensation of melamine and dicyandiamide in air and in ammonia. By varying the C3N4 content from 2 to 75 wt %, the mesoporosity can be tuned from 8 to 40 nm. A systematic study of CO oxidation turnover numbers in the absence and in the presence of hydrogen over the composites loaded with well-calibrated 2-4 nm gold nanoparticles clearly shows that (1) the chemical composition of the support surface has much less impact on PROX (preferential oxidation of CO in excess hydrogen) than on dry CO oxidation, (2) NH2-terminated supports are as active as OH-terminated supports in PROX, (3) hydrogen/water-mediated CO oxidation pathways are active on C3N4-based Au catalysts, and (4) PROX activity requires a rather large porosity (40 nm), which suggests the involvement of much larger intermediates than the usually postulated peroxo-type species.

Deep ocean metagenomes provide insight into the metabolic architecture of bathypelagic microbial communities

The deep sea, the largest ocean’s compartment, drives planetary-scale biogeochemical cycling. Yet, the functional exploration of its microbial communities lags far behind other environments. Here we analyze 58 metagenomes from tropical and subtropical deep oceans to generate the Malaspina Gene Database. Free-living or particle-attached lifestyles drive functional differences in bathypelagic prokaryotic communities, regardless of their biogeography. Ammonia and CO oxidation pathways are enriched in the free-living microbial communities and dissimilatory nitrate reduction to ammonium and H2 oxidation pathways in the particle-attached, while the Calvin Benson-Bassham cycle is the most prevalent inorganic carbon fixation pathway in both size fractions. Reconstruction of the Malaspina Deep Metagenome-Assembled Genomes reveals unique non-cyanobacterial diazotrophic bacteria and chemolithoautotrophic prokaryotes. The widespread potential to grow both autotrophically and heterotrophically suggests that mixotrophy is an ecologically relevant trait in the deep ocean. These results expand our understanding of the functional microbial structure and metabolic capabilities of the largest Earth aquatic ecosystem.

Pt and Ir supported on mixed Ce0.97Ru0.03O2 oxide as low-temperature CO oxidation catalysts

Pt and Ir catalysts (3% w/w) supported on Ce0.97Ru0.03O2 were synthesized and successfully tested in a low-temperature CO oxidation process. The CO oxidation was followed in-operation, by FTIR spectroscopy. The catalysts were characterized by SEM-EDS, HTEM, XRD, DRS UV–vis, XPS techniques and BET isotherms. It was found that Pt and Ir nanoparticles on Ce0.97Ru0.03O2 drastically improved the CO oxidation in comparison to CeO2, showing the best performance the Pt/ Ce0.97Ru0.03O2 system. From the FTIR studies, a route for CO oxidation was proposed. The CO oxidation pathway in Ce0.97Ru0.03O2 considers that CO was adsorbed at the Ce and Ru sites, while O2 is adsorbed on the surface oxygen vacancies, being activated by nearby Ru species. Subsequently, the activated oxygen reacts with CO linked to Ce and Ru to produce CO2. Also, Pt and Ir promotes oxygen vacancies, increasing the activation-adsorption of O2 and, consequently, the activity of the catalyst was improved.

A Three-step Global Kinetic Mechanism for Predicting Extinction Strain Rate of Syngas-air Nonpremixed Flames

ABSTRACT A systematic survey of chemical kinetic mechanisms (both simplified and global) shows an absence of a robust kinetic mechanism that can accurately predict characteristics of syngas-air nonpremixed flames. In this work, a three-step global kinetics mechanism is proposed for predicting the extinction strain rate (ag ) of syngas-air nonpremixed flames. The available experimental ag data-set from the Tsuji type burner was used to evaluate the performance of six syngas kinetics models (four simplified and two global). For this, 2D-planar computations were performed to obtain ag values using four CO/H2 ratios (1, 3, 5, and 29). The results showed that all the simplified kinetics mechanisms overpredicted the ag values in the range of 16–224% for the four CO/H2 ratios. In the case of the global kinetics models namely, CFFR and WO, except for CO/H2 ratio of 29, CFFR underpredicted ag values by 22–55%. WO underpredicted ag by 10–44% for CO/H2 = 1 and overpredicted ag by 19–58% for CO/H2 = 3 and 5. For CO/H2 = 29, WO overpredicted ag values by 151–205%. For CO/H2 = 1, WO underpredicted ag due to two reasons, (1) double accounting of CO hydroxyl oxidation path and, (2) suppression of H2 oxidation pathways in four-step global JL mechanism, a source for the construction of WO mechanism. From the overall perceptive, WO has performed better compared to other mechanisms. Hence, WO was chosen for further optimization using experimental ag data as a target. Sensitivity analysis in terms of ag and maximum flame temperature (TF ) was performed for WO using two CO/H2 ratios (1 and 5). It was found that for CO/H2 = 1 and 5, ag is most sensitive to Rxn1 (H2 + 0.5O2↔ H2O) and Rxn2 (CO + 0.5O2 → CO2). Results from sensitivity analysis, 0D (PSR) computations, and 2D computations have shown that the improper quantification of CO and H2 oxidation pathways leads to inaccurate ag prediction by the WO model. Based on these new insights, a modified three-step WO syngas kinetics model (WO-Opt) is proposed for predicting the extinction strain rate of syngas-air nonpremixed flames. The WO-Opt model was validated against ag experimental data. Compared to the WO model, ag predictions obtained from the modified WO-Opt model were in good agreement with the syngas-air nonpremixed flames experiments.

Surface Defects as Ingredients That Can Improve or Inhibit the Pathways for CO Oxidation at Low Overpotentials Using Pt(111)-Type Catalysts

M.J.S.F. is grateful to CAPES (Brazil). A.A.T. acknowledges CAPES (Processo 88887.124173/2014-00-2013), CNPq (Processo 554610/2010-8), and FAPEMA (APP-UNIVERSAL 01150-070). J.M.F. and E.H. thank the Ministerio de Ciencia e Innovacion (Spain) for financial support through the project PID2019-105653GB-I00.

Oxophilicity Drives Oxygen Transfer at a Palladium–Silver Interface for Increased CO Oxidation Activity

A single-layer AgOx phase grown on Ag(111) efficiently transfers oxygen to Pd domains at room temperature, rendering the Pd-decorated surface highly reactive toward CO oxidation. Oxygen transfer from AgOx to Pd and the surface reactivity toward CO were investigated as a function of the Pd coverage using X-ray photoelectron spectroscopy, surface infrared spectroscopy of adsorbed CO, temperature-programmed reaction spectroscopy, and density functional theory (DFT) calculations. Our results show that all of the oxygen from the AgOx layer (∼0.375 monolayer) migrates to the surface of Pd during formation of a nearly complete Pd bilayer at 300 K and that the oxygen coverages generated on Pd increase as the Pd cluster size decreases, reaching values that exceed the oxygen concentration in the AgOx layer by as much as a factor of 2. Experimental measurements and DFT calculations show that preferential binding of oxygen on the edges of the Pd clusters enhances the oxygen coverage on Pd clusters of decreasing size and produces a heterogeneous spatial distribution of oxygen. CO adsorbs in high coverages at 100 K by binding on both the terraces and O-rich edges of the Pd clusters. During subsequent heating, oxidation of the adsorbed CO consumes nearly all of the oxygen that transferred from AgOx to the Pd domains; in contrast, the pure AgOx layer exhibits limited reactivity toward CO adsorbed at 100 K. These results demonstrate that differences in oxophilicity drive facile oxygen transfer from Ag to the edges of Pd nanoclusters and thereby give rise to an efficient pathway for CO oxidation on bimetallic PdAg surfaces. The cooperation between the Pd and Ag domains results in near-interfacial chemistry that may be broadly important in catalysis by bimetallic alloys.