A DFT Study of CO Catalytic Oxidation by N2O or O2 on the Co3O4(110) Surface

Xu, Xianglan; Yang, Euiseob; Li, Junqian; Li, Yang; Chen, Wenkai

doi:10.1002/cctc.200900115

Cited by 78 publications

(61 citation statements)

References 75 publications

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“…11 Given the fact that our Co 3 O 4 _Cu2 nanowires are polycrystalline without any specific surface facet control, the comparable catalytic activity indicates that the current Cu 2+ substitution method is as effective as the surface facet control strategy. Previous theoretical studies 8,18,25,26 have investigated CO oxidation only on pure Co 3 O 4 surfaces. To get a deeper insight into the enhanced effect of Cu 2+ cations on the catalytic activity of the Co 3 O 4 _Cux nanowires, we performed DFT+U calculations (see Supporting Information for details).…”

Section: ■ Introductionmentioning

confidence: 99%

Enhancing Catalytic CO Oxidation over Co₃O₄ Nanowires by Substituting Co²⁺ with Cu²⁺

Zhou¹,

Cai²,

et al. 2015

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Co 3 O 4 is an attractive earth-abundant catalyst for CO oxidation, and its high catalytic activity has been attributed to Co 3+ cations surrounded by Co 2+ ions. Hence, the majority of efforts for enhancing the activity of Co 3 O 4 have been focused on exposing more Co 3+ cations on the surface. Herein, we enhance the catalytic activity of Co 3 O 4 by replacing the Co 2+ ions in the lattice with Cu 2+ . Polycrystalline Co 3 O 4 nanowires for which Co 2+ is substituted with Cu 2+ are synthesized using a modified hydrothermal method. The Cusubstituted Co 3 O 4 _Cux polycrystalline nanowires exhibit much higher catalytic activity for CO oxidation than pure Co 3 O 4 polycrystalline nanowires and catalytic activity similar to those single crystalline Co 3 O 4 nanobelts with predominantly exposed most active {110} planes. Our computational simulations reveal that Cu 2+ substitution for Co 2+ is preferred over Co 3+ both in the Co 3 O 4 bulk and at the surface. The presence of Cu dopants changes the CO adsorption on the Co 3+ surface sites only slightly, but the oxygen vacancy is more favorably formed in the bonding of Co 3+ −O−Cu 2+ than in Co 3+ −O−Co 2+ . This study provides a general approach for rational optimization of nanostructured metal oxide catalysts by substituting inactive cations near the active sites and thereby increasing the overall activity of the exposed surfaces. ■ INTRODUCTIONCarbon monoxide (CO) emission from transportation and industrial activities is harmful to both human health and the environment. Currently, CO emission is effectively reduced, mainly through catalytic oxidation over catalysts. 1−4 The most active catalysts for CO oxidation are noble metals, but they are expensive and are of limited supply. Co 3 O 4 has emerged as an attractive alternative catalyst for CO oxidation because of its optimal CO adsorption strength, low barrier for CO reaction with lattice O, and excellent redox capacity. 1,5−8 A breakthrough on Co 3 O 4 for catalytic CO oxidation showing that Co 3 O 4 nanorods with predominantly exposed {110} planes exhibit a much higher catalytic activity for CO oxidation and larger resistance to deactivation by water than Co 3 O 4 nanoparticles was reported by Xie et al. 9 The high catalytic activity of Co 3 O 4 {110} planes is attributed to its higher concentration of Co 3+ cations (correspondingly fewer Co 2+ cations) than other crystal planes, since only Co 3+ cations surrounded by Co 2+ ions are active for catalytic oxidation of CO. 10,11 Subsequently, a number of Co 3 O 4 nanostructures, ranging from nanobelts, nanospheres, nanocubes, and nanotubes to nanowires, have been synthesized with the purpose of preferentially exposing Co 3+ cations. 11−14 Nevertheless, regardless of the morphology of the Co 3 O 4 nanostructures, even the highly active Co 3 O 4 {110} planes still contain Co 2+ cations, which have been assumed to be inactive for catalytic oxidation of CO, 9−11 and ultimately limits the catalytic activity of Co 3 O 4 for CO oxidation. Therefore, substituting Co 2+ with...

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Section: ■ Introductionmentioning

confidence: 99%

Enhancing Catalytic CO Oxidation over Co₃O₄ Nanowires by Substituting Co²⁺ with Cu²⁺

Zhou¹,

Cai²,

et al. 2015

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“…The health significance of CO is due to the fact that it is able to combine irreversibly with the iron atom of hemoglobin to produce carboxyhemoglobin, which its formation avoids the normal oxygencarrying capacity of the blood [11]. Therefore, both the reduction of N2O and the oxidation of CO have been one of the major topics to reduce these toxic gases, respectively [12,13].…”

Section: Introductionmentioning

confidence: 99%

Al- or Si-decorated graphene oxide: A favorable metal-free catalyst for the N2O reduction

Esrafili

Sharifi

Nematollahi

2016

Applied Surface Science

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“…[9] It should be noted that CO oxidation through the reaction path of CO(g) + O s on other metal oxides, such as Co 3 O 4 , cannot take place, owing to the large adsorption energy difference of molecular CO on metallic Co and on the lattice oxygen sites (as high as 0.90 eV). [38] In addition, the DFT results of Burgel et al also show that the CO oxidation on Au-O anionic clusters obeys the E-R mechanism whereas the CO oxidation on Au-O cationic clusters can proceed through both E-R and L-H mechanisms. [39] The detailed discussion about the influence of the solid structure on the reaction mechanism (E-R versus L-H) will be addressed in a separate paper.…”

Section: Co Oxidation On Metal Surfacesmentioning

confidence: 99%

The Mechanism of Low‐Temperature CO Oxidation on IB Group Metals and Metal Oxides

Wei¹,

Pang

et al. 2011

ChemCatChem

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CO oxidation on the IB group metals [Cu(111), Ag(111), and Au(111)] and corresponding metal oxides [Cu2O(100), Ag2O(100), and Au2O(100)] has been studied by means of density functional theory calculations with the aim to shed light on the reaction mechanism and catalytic activity of metals and metal oxides. The calculated results show that 1) the molecular oxygen mechanism is favored on Ag(111) and Au(111), but the atomic oxygen mechanism is favored on Cu(111); 2) the metal‐terminated metal oxide shows very low activity for CO oxidation; 3) the lattice oxygen can react either with gas phase CO or the absorbed CO molecule on oxygen‐terminated metal oxides; and 4) the reaction barrier for CO oxidation follows the order of M2O(100)–O<M(111)<M2O(100)–M (M=Cu, Ag, Au); namely the M2O(100)–O shows higher activity than does the corresponding metal. By analyzing the factor that controls the energy barrier, it was found that the interaction energy between two CO molecules and one O atom at the transition state plays an important role in determining the trend in the barrier.

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A DFT Study of CO Catalytic Oxidation by N₂O or O₂ on the Co₃O₄(110) Surface

Cited by 78 publications

References 75 publications

Enhancing Catalytic CO Oxidation over Co₃O₄ Nanowires by Substituting Co²⁺ with Cu²⁺

Enhancing Catalytic CO Oxidation over Co₃O₄ Nanowires by Substituting Co²⁺ with Cu²⁺

Al- or Si-decorated graphene oxide: A favorable metal-free catalyst for the N2O reduction

The Mechanism of Low‐Temperature CO Oxidation on IB Group Metals and Metal Oxides

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A DFT Study of CO Catalytic Oxidation by N2O or O2 on the Co3O4(110) Surface

Cited by 78 publications

References 75 publications

Enhancing Catalytic CO Oxidation over Co3O4 Nanowires by Substituting Co2+ with Cu2+

Enhancing Catalytic CO Oxidation over Co3O4 Nanowires by Substituting Co2+ with Cu2+

Al- or Si-decorated graphene oxide: A favorable metal-free catalyst for the N2O reduction

The Mechanism of Low‐Temperature CO Oxidation on IB Group Metals and Metal Oxides

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A DFT Study of CO Catalytic Oxidation by N₂O or O₂ on the Co₃O₄(110) Surface

Enhancing Catalytic CO Oxidation over Co₃O₄ Nanowires by Substituting Co²⁺ with Cu²⁺

Enhancing Catalytic CO Oxidation over Co₃O₄ Nanowires by Substituting Co²⁺ with Cu²⁺