Wet oxidation of phenol over transition metal oxide catalysts supported on Ce0.65Zr0.35O2 prepared by continuous hydrothermal synthesis in supercritical water

Kim, Kyoung-Hun; Kim, Jeong‐Rang; Ihm, Son‐Ki

doi:10.1016/j.jhazmat.2009.01.110

Cited by 36 publications

(30 citation statements)

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“…X-ray photoelectron spectroscopy (XPS) is the method that allows monitoring changes in the local environment of ions and their oxidations states [17]. The surface chemical states of Ce cations have been explored so far preferably for undoped CeO 2 [18][19][20][21][22][23], CeO 2 -based solid solutions [24][25][26], and composites composed of CeO 2 and transition metals or their oxides [27][28][29][30][31][32][33][34]. It was shown that properties of composite materials (redox properties, formation of surface and bulk oxygen vacancies, oxygen storage and release) can be optimised through the variation of the CeO 2 /Me(Me x O y ) ratios.…”

Section: Introductionmentioning

confidence: 99%

Identification of surface composition and chemical states in composites comprised of phases with fluorite and perovskite structures by X-ray photoelectron spectroscopy

Konysheva

Francis

2013

Applied Surface Science

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Keywords:X-ray photoelectron spectroscopy (XPS) Surface composition Composites with perovskite and fluorite structures Oxidation state of cerium cations Binding energy a b s t r a c t X-ray photoelectron spectroscopy (XPS) has been used to explore the cation rearrangement between the surface and bulk of grains and the surface chemical states of Ce, Mn, Co, Sr, and O ions in the single phase CeO 2 -based solid solutions and in the two phase (100 − x)La 0.6 Sr 0.4 CoO 3 -xCeO 2 (LSCCx) and (100 − x)La 0.8 Sr 0.2 MnO 3 -xCeO 2 (LSMCx) composites. The well-resolved Ce 3d 5/2 and Ce 3d 3/2 spin-orbit components were determined to study the Ce 4+ to Ce 3+ electronic transition at the surface. The surface of the LSCCx and LSMCx (x = 8-40 mol%) composites is depleted in cerium. Both Ce 4+ and Ce 3+ cations were revealed. The surface fraction of Ce 4+ cations increases with the rise in CeO 2 content in both systems, but it is higher by about a factor of two in the LSCC composites. A strong enrichment of the surface by Co cations was observed for the composites LSCCx (x = 8-40 mol%), implying that the presence of cerium could facilitate the Co surface segregation. A slight Sr surface enrichment compared to the nominal stoichiometry was found for La 0.6 Sr 0.4 CoO 3 , CeO 2 -based solid solutions, LSCC57, and LSMCx (x = 10-57) composites. In contrast, the surface of the LSCCx (x = 10-37) composites is slightly depleted in strontium cations. The O 1s spectra of the LSCC and LSMC composites contain several contributions associated with the lattice oxygen related to the phases with the perovskite and fluorite structures as well as with different surface states. Their contributions vary with CeO 2 content and a chemical origin of the transition metal cations on the B-site in the perovskite structure. The Ce 2 (CO 3 ) 3 -based phase seems to exist at the surface of grains and crystallites in the LSCC57 and LSCM composites.

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Section: Introductionmentioning

confidence: 99%

Identification of surface composition and chemical states in composites comprised of phases with fluorite and perovskite structures by X-ray photoelectron spectroscopy

Konysheva

Francis

2013

Applied Surface Science

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“…Metal oxides have been widely used as catalytic materials for various applications in chemical, petroleum, and environmental industries [1][2][3][4]. Especially, copper oxides have been widely examined as combustion catalysts in various forms such as bulk metal oxides or supported metal oxides [5][6][7][8][9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Preparation of Copper Oxide with High Surface Area Associated with Mesoporous Silica

Suh

Ihm

2010

Top Catal

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“…CWAO consists in the total oxidation of the organic species present in effluents to CO 2 , N 2 and H 2 O under relatively mild conditions of temperature and pressure, using oxygen or air as the oxidizing source, provided that a suitable catalyst is used (Gomes et al, 2008;Parvas et al, 2014). Using proper catalysts for catalytic wet oxidation (CWO) not only reduces the severity of reaction conditions but also decomposes even refractory pollutants (Kim et al, 2009;Mishra et al, 1995). Homogenous transition metals (Fe 2+ , Cu 2+ ) may be suitable catalysts, but the dissolved ions need to be separated at the end of the process (Besson et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

“…Moreover the active component of non-noble metal catalyst is largely leaching, therefore, non-noble metal catalysts mainly are focused on improving their stability (Jing et al, in press). Transition metal oxide catalysts are widely studied as an alternative in the CWAO process even if they show rather lower activity than noble metals (Arena et al, 2010;Gomes et al, 2005;Kim et al, 2009). The solution of this problem is using some efficient supports with a better capacity to activate oxygen and facilitating the oxygen transfer from the dissolved phase to the active sites (Kim et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

“…Transition metal oxide catalysts are widely studied as an alternative in the CWAO process even if they show rather lower activity than noble metals (Arena et al, 2010;Gomes et al, 2005;Kim et al, 2009). The solution of this problem is using some efficient supports with a better capacity to activate oxygen and facilitating the oxygen transfer from the dissolved phase to the active sites (Kim et al, 2009). TiO 2 , CeO 2 and ZrO 2 were proved to be stable and easily available supporting materials (Wang et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

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Catalytic wet air oxidation of phenol over ultrasound-assisted synthesized Ni/CeO2–ZrO2 nanocatalyst used in wastewater treatment

Parvas

Haghighi

Allahyari

2019

Arabian Journal of Chemistry

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Non-noble metal Ni with different loadings was coated on precipitated CeO 2 -ZrO 2 support by the sonochemistry method and examined for catalytic wet air oxidation of phenol. The structure of the nanocatalysts was determined by BET, FESEM, XRD, and FTIR analyses. The results showed non-uniform morphology of the nanocatalyst at lower Ni contents changed to homogenous morphology with spherical nano particles at higher Ni contents. While the size of NiO crystals remained constant with rising Ni content, the crystallinity of NiO significantly increased. If the crystallinity of NiO was 100% in 20% wt Ni/CeO 2 -ZrO 2 , the crystallinity of NiO in 5% wt Ni was found to be 41.13%. The average particle size in Ni(15%)/CeO 2 -ZrO 2 was 77 nm in which 85.71% of particle diameters were less than 100 nm. Catalytic wet air oxidation of phenol with different Ni loadings indicated improvement of phenol destruction at higher amounts of active phase. Removal of phenol increased with increasing catalyst loading from 4 to 9.0 g/l but further increase to 10 g/l declined the catalyst reactivity. ª 2014 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

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Wet oxidation of phenol over transition metal oxide catalysts supported on Ce0.65Zr0.35O2 prepared by continuous hydrothermal synthesis in supercritical water

Cited by 36 publications

References 23 publications

Identification of surface composition and chemical states in composites comprised of phases with fluorite and perovskite structures by X-ray photoelectron spectroscopy

Identification of surface composition and chemical states in composites comprised of phases with fluorite and perovskite structures by X-ray photoelectron spectroscopy

Preparation of Copper Oxide with High Surface Area Associated with Mesoporous Silica

Catalytic wet air oxidation of phenol over ultrasound-assisted synthesized Ni/CeO2–ZrO2 nanocatalyst used in wastewater treatment

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