Highly Ordered Mesoporous α-Mn2O3 for Catalytic Decomposition of H2O2 at Low Temperatures

Park, Jung‐Nam; Shon, Jeong Kuk; Jin, Mingshi; Hwang, Seong Hee; Park, Gwi Ok; Boo, Jin‐Hyo; Han, Tae Hee; Kim, Ji Man

doi:10.1246/cl.2010.493

Cited by 31 publications

(5 citation statements)

References 32 publications

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“…The mesoporous silica template (KIT-6) was synthesized following previously reported methods [26,[36][37][38][39][40]. A triblock copolymer (Pluronic P123, EO 20 PO 70 EO 20 , Aldrich) and tetraethylorthosilicate (TEOS, Aldrich) were utilized as the structure-directing agent and framework source, respectively.…”

Section: Catalyst Synthesismentioning

confidence: 99%

Room-temperature CO oxidation over a highly ordered mesoporous RuO2 catalyst

Park

Shon

Jin

et al. 2011

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Highly ordered mesoporous ruthenium dioxide (meso-RuO 2 ) has been successfully synthesized by controlling the surface hydrophobicity of a mesoporous silica template (KIT-6) via a nano-replication method. The meso-RuO 2 material, thus obtained, exhibits a well-defined mesostructure and high surface area (131 m 2 g -1 ). The physicochemical properties of the meso-RuO 2 material are characterized by electron microscopy, X-ray diffraction, N 2 adsorption-desorption, temperature programmed techniques, and X-ray photoelectron spectroscopy. Pretreatment of the meso-RuO 2 catalyst under different gas environments (O 2 , H 2 and CO) strongly affects the catalytic activity towards CO oxidation. The meso-RuO 2 , pretreated by O 2 flowing at 200°C, exhibited excellent catalytic activity for CO oxidation, 100% CO conversion with long-term stability at room temperature, whereas the meso-RuO 2 catalysts with pretreatment under other conditions are not very active at room temperature. It is found that the surface oxygen species generated on the meso-RuO 2 during O 2 pretreatment at 200°C provide CO oxidation activity at room temperature.

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Section: Catalyst Synthesismentioning

confidence: 99%

Room-temperature CO oxidation over a highly ordered mesoporous RuO2 catalyst

Park

Shon

Jin

et al. 2011

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“…Reactions of H 2 O 2 with metal and metal oxide surfaces have been studied to some extent − mainly due to their importance in areas ranging from catalysis to geo- and environmental chemistry and nuclear technology. Due to the complexity of the systems involved, which is dominated by the heterogeneity caused by the introduction of a solid phase, several mechanistic details remain to be understood.…”

Section: Introductionmentioning

confidence: 99%

Mechanism of H₂O₂ Decomposition on Transition Metal Oxide Surfaces

et al. 2012

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We performed an experimental and density functional theory (DFT) investigation of the reactions of H 2 O 2 with ZrO 2 , TiO 2 , and Y 2 O 3 . In the experimental study we determined the reaction rate constants, the Arrhenius activation energies, and the activation enthalpies for the processes of adsorption and decomposition of H 2 O 2 on the surfaces of nano-and micrometersized particles of the oxides. The experimentally obtained enthalpies of activation for the decomposition of H 2 O 2 catalyzed by these materials are 30 ± 1 kJ•mol −1 for ZrO 2 , 34 ± 1 kJ•mol −1 for TiO 2 , and 44 ± 5 kJ•mol −1 for Y 2 O 3 . In the DFT study, cluster models of the metal oxides were used to investigate the mechanisms involved in the surface process governing the decomposition of H 2 O 2 . We compared the performance of the B3LYP and M06 functionals for describing the adsorption energies of H 2 O 2 and HO • onto the oxide surfaces as well as the energy barriers for the decomposition of H 2 O 2 . The DFT models implemented can describe the experimental reaction barriers with good accuracy, and we found that the decomposition of H 2 O 2 follows a similar mechanism for all the materials studied. The average absolute deviation from the experimental barriers obtained with the B3LYP functional is 6 kJ•mol −1 , while with the M06 functional it is 3 kJ•mol −1 . The differences in the affinity of the different surfaces for the primary product of H 2 O 2 decomposition, the HO radical, were also addressed both experimentally and with DFT. With the experiments we found a trend in the affinity of HO • toward the surfaces of the oxides, depending on the type of oxide. This trend is successfully reproduced with the DFT calculations. We found that the adsorption energy of HO • varies inversely with the ionization energy of the metal cation present in the oxide.

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“…The reactivity of hydrogen peroxide toward metal oxide surfaces has received increasing attention during the past decade. − The main reason for this is the importance of such processes in nuclear technological installations . These studies have shown that hydrogen peroxide undergoes catalytic decomposition, primarily to form adsorbed hydroxyl radicals, on oxide surfaces of the type M x O y .…”

Section: Introductionmentioning

confidence: 99%

Formation of H₂O₂ in TiO₂ Photocatalysis of Oxygenated and Deoxygenated Aqueous Systems: A Probe for Photocatalytically Produced Hydroxyl Radicals

2014

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The formation of H2O2 in oxygenated and deoxygenated aqueous solutions using immobilized TiO2 illuminated by black light (365 nm) was studied to verify the presence of hydroxyl radicals in TiO2 photocatalysis. In oxygen containing systems, formation of H2O2 proceeds through reduction of molecular oxygen by conduction band electrons or by recombination of hydroxyl radicals. In oxygen free solutions recombination of hydroxyl radicals constitutes the only pathway to H2O2 formation. Detection of H2O2 in absence of oxygen therefore serves as an indicator for hydroxyl radical formation. The H2O2 concentration was determined using the Ghormley triiodide method. It was found that a significant amount of H2O2 was produced in the deoxygenated aqueous solutions supporting the hypothesis of hydroxyl radical production in photocatalysis. To further elucidate the origin of the H2O2, experiments using the radical scavenger tris(hydroxymethyl)aminomethane (Tris) were conducted. The results showed that the H2O2 concentration increased in the oxygenated system as Tris protects the H2O2 from decomposition by hydroxyl radicals. In the deoxygenated system, no H2O2 could be detected due to hydroxyl radical scavenging by Tris, which prevents H2O2 formation. The results presented support the hypothesis that the hydroxyl radical is the primary oxidant in aqueous TiO2 photocatalysis.

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Highly Ordered Mesoporous α-Mn2O3 for Catalytic Decomposition of H2O2 at Low Temperatures

Abstract: Highly ordered mesoporous α-Mn2O3 with well-defined mesopores, high surface area, and high oxygen vacancy exhibits excellent catalytic activity toward H2O2 decomposition at low temperature.

Cited by 31 publications

References 32 publications

Room-temperature CO oxidation over a highly ordered mesoporous RuO2 catalyst

Room-temperature CO oxidation over a highly ordered mesoporous RuO2 catalyst

Mechanism of H₂O₂ Decomposition on Transition Metal Oxide Surfaces

Formation of H₂O₂ in TiO₂ Photocatalysis of Oxygenated and Deoxygenated Aqueous Systems: A Probe for Photocatalytically Produced Hydroxyl Radicals

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Highly Ordered Mesoporous α-Mn2O3 for Catalytic Decomposition of H2O2 at Low Temperatures

Abstract: Highly ordered mesoporous α-Mn2O3 with well-defined mesopores, high surface area, and high oxygen vacancy exhibits excellent catalytic activity toward H2O2 decomposition at low temperature.

Cited by 31 publications

References 32 publications

Room-temperature CO oxidation over a highly ordered mesoporous RuO2 catalyst

Room-temperature CO oxidation over a highly ordered mesoporous RuO2 catalyst

Mechanism of H2O2 Decomposition on Transition Metal Oxide Surfaces

Formation of H2O2 in TiO2 Photocatalysis of Oxygenated and Deoxygenated Aqueous Systems: A Probe for Photocatalytically Produced Hydroxyl Radicals

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Mechanism of H₂O₂ Decomposition on Transition Metal Oxide Surfaces

Formation of H₂O₂ in TiO₂ Photocatalysis of Oxygenated and Deoxygenated Aqueous Systems: A Probe for Photocatalytically Produced Hydroxyl Radicals