Hydrophobic Polymer-Coated Metal Oxide Catalysts for Effective Low-Temperature Oxidation of CO under Moisture-Rich Conditions

Chen, Chun‐Hu; Njagi, Eric C.; Sun, Shih-Po; Genuino, Homer C.; Hu, Boxun; Suib, Steven L.

doi:10.1021/cm100724f

Cited by 34 publications

(36 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The binding energies of the Mo 3d 3/2 and 3d 5/2 transitions with an energy separation of 3.1 eV correspond well to the Mo 6+ state in a MnOx environment ( Figure S-3). 37,38 Following the charge imbalance in the octahedral framework with the presence of VI Mn 3+ (the superscript of VI stands for VI-fold coordination) compensated by VIII K + sitting in the tunnel sites, the resulting structural formula is shown as follows …”

Section: Discussionmentioning

confidence: 99%

Structural Distortion of Molybdenum-Doped Manganese Oxide Octahedral Molecular Sieves for Enhanced Catalytic Performance

et al. 2015

Self Cite

View full text Add to dashboard Cite

Due to the excellent catalytic performance of manganese oxide (K-OMS-2) in a wide range of applications, incorporation of various dopants has been commonly applied for K-OMS-2 to acquire additional functionality or activities. However, the understanding of its substitution mechanism with respect to the catalytic performance of doped K-OMS-2 materials remains unclear. Here we present the structural distortion (from tetragonal to monoclinic cell) and morphological evolution in K-OMS-2 materials by doping hexavalent molybdenum. With a Mo-to-Mn ratio of 1:20 (R-1:20) in the preparation, the resultant monoclinic K-OMS-2 shows a small equidimensional particle size (∼15 nm), a high surface area of 213 m(2) g(-1), and greatly improved catalytic activity toward CO oxidation with lower onset temperatures (40 °C) than that of pristine K-OMS-2 (above 130 °C). HR-TEM analyses reveal direct evidence of structural distortion on the cross-section of 2 × 2 tunnels with the absence of 4-fold rotation symmetry expected for a tetragonal cell, which are indexed using a monoclinic cell. Our results suggest that substitution of Mo(6+) for Mn(3+) (rather than Mn(4+)) coupled with the vacancy generation results in a distorted structure and unique morphology. The weakened Mn-O bonds and Mn vacancies associated with the structural distortion may be mainly responsible for the enhanced catalytic activity of monoclinic K-OMS-2 instead of dopant species.

show abstract

Section: Discussionmentioning

confidence: 99%

Structural Distortion of Molybdenum-Doped Manganese Oxide Octahedral Molecular Sieves for Enhanced Catalytic Performance

et al. 2015

Self Cite

View full text Add to dashboard Cite

show abstract

“…For instance, Suib et al. took advantage of a hydrophobic polymer‐coated Co 3 O 4 catalyst for the effective low‐temperature oxidation of CO with 3 % moisture . Furthermore, Co 3 O 4 nanoparticles in situ grown on hydrophobic carbon nanotubes were also proven to be less sensitive to water vapor and gave a 100 % conversion of CO at 25–200 °C with 3–10 % moisture …”

Section: Figurementioning

confidence: 99%

Cobalt‐Doped K‐OMS‐2 Nanofibers: A Novel and Efficient Water‐Tolerant Catalyst for the Oxidation of Carbon Monoxide

et al. 2017

View full text Add to dashboard Cite

Cobalt-doped manganese octahedral molecular sieves with an ordered cryptomelanes tructure (OMS-2) were synthesized by ao ne-step hydrothermalm ethod. The cobalt precursor was directly added into the solution before crystallization to allow its incorporation into the mixed-valent framework of K-OMS-2. The structure, redox properties, and surface hydrophobicity of Co-doped K-OMS-2 were examined by X-ray diffraction, FTIR spectroscopy,R amans pectroscopy,S EM,T EM, N 2 sorption, temperature-programmed reduction by H 2 ,X -ray photoelectron spectroscopy,a nd water contact-angle system. The incorporation of Co induced am orphological change in K-OMS-2 from nanorods to nanofibers and an increase in the specific surfacea rea from 70.6 to 188.3 m 2 g À1 .C o-doped K-OMS-2 was shown to be able to completely convert CO at 100 8Ci nt he presenceo fa pproximately 3% water vapor.T he promotion effect of Co on the catalytic activity is believed to originate from the enhanced redox capacity and surfacea rea of K-OMS-2, whereas the improved surfaceh ydrophobicity may induce superiorw ater-tolerant performance.CatalyticC Oo xidation hasb een extensively investigated and has already been applied in the field of air purification,a utomotive exhaust cleaning, CO removal of cigarettes moke, and CO 2 lasers. [1] However,f or the above purposes, the presence of water vapor inevitably leads to catalystd eactivation through temporary poisoning of the exposed active sites. [2] Such strict operation conditions have thus stimulated an increase in the demandt od evelop highly efficient and water-tolerantc atalysts for CO oxidation. Noble-metal catalysts such as Pd, Pt, and Au have been widely recognized as preferred choices, but both high costs and finite resources limit their application. [3] Alternatively,aseries of cheap transition-metal oxides (i.e.,C uO,

show abstract

“…[21][22][23] Chen et al synthesized hydrophobic metal oxides coated with a protective layer of polydimethylsiloxane to prevent water poisoning. [24] However, the activity was very low implying that the polymer film was also limiting the reactants from accessing the active sites. Shen et al synthesized a polymer nanofilm coated Fe 3 Co 16 O x catalyst which gave good activity for CO oxidation under the dry conditions.…”

Section: Introductionmentioning

confidence: 99%

Effect of High Temperature on Swellable Organically Modified Silica (SOMS) and Its Application for Preferential CO Oxidation in H₂ Rich Environment

et al. 2020

View full text Add to dashboard Cite

show abstract

Hydrophobic Polymer-Coated Metal Oxide Catalysts for Effective Low-Temperature Oxidation of CO under Moisture-Rich Conditions

Cited by 34 publications

References 26 publications

Structural Distortion of Molybdenum-Doped Manganese Oxide Octahedral Molecular Sieves for Enhanced Catalytic Performance

Structural Distortion of Molybdenum-Doped Manganese Oxide Octahedral Molecular Sieves for Enhanced Catalytic Performance

Cobalt‐Doped K‐OMS‐2 Nanofibers: A Novel and Efficient Water‐Tolerant Catalyst for the Oxidation of Carbon Monoxide

Effect of High Temperature on Swellable Organically Modified Silica (SOMS) and Its Application for Preferential CO Oxidation in H₂ Rich Environment

Contact Info

Product

Resources

About

Hydrophobic Polymer-Coated Metal Oxide Catalysts for Effective Low-Temperature Oxidation of CO under Moisture-Rich Conditions

Cited by 34 publications

References 26 publications

Structural Distortion of Molybdenum-Doped Manganese Oxide Octahedral Molecular Sieves for Enhanced Catalytic Performance

Structural Distortion of Molybdenum-Doped Manganese Oxide Octahedral Molecular Sieves for Enhanced Catalytic Performance

Cobalt‐Doped K‐OMS‐2 Nanofibers: A Novel and Efficient Water‐Tolerant Catalyst for the Oxidation of Carbon Monoxide

Effect of High Temperature on Swellable Organically Modified Silica (SOMS) and Its Application for Preferential CO Oxidation in H2 Rich Environment

Contact Info

Product

Resources

About

Effect of High Temperature on Swellable Organically Modified Silica (SOMS) and Its Application for Preferential CO Oxidation in H₂ Rich Environment