Transition metal oxides dispersed on Ti-MCM-41 hybrid core-shell catalysts for the photocatalytic degradation of Congo red colorant

U. Arellano, J. A. Wang, L. F. Chen, M. Asomoza, A. Guzmán, S. Solís, A. Estrella, S. Cipagauta, L. E. Noreña

Research output: Contribution to journalArticle

Abstract

Hybrid core-shell catalysts were synthesized by transition metal (Fe, V and Cu) oxides dispersed on Ti doped mesoporous Ti-MCM-41 (noted as TiM) and their crystalline structures, morphologies, metal oxidation states and optical properties were studied with a variety of characterization techniques. All the catalysts showed a core-shell morphological feature. Fe2O3, CuO and V2O5 enriched the catalyst surface forming an oxide shell on the Ti-MCM-41 core. Predominant Fe3+, Cu2+ and V5+ ions coexisted with a small part of Fe2+, Cu+ and V4+ ions generating Fe3+/Fe2+, Cu2+/Cu+ and V5+/V4+ couples in the corresponding catalyst. The UV–vis spectroscopic analysis showed a shift of the prohibited band energy towards the visible region after the metal oxides loading. In the photocatalytic degradation reaction of Congo red (CR) in an aqueous solution, the catalysts exhibited an activity order as: Cu/TiM > Fe/TiM > V/TiM > TiM. The photocatalytic activity resulted from the affinity of the anionic colorant with the positively charged surface of the catalysts and correlated well with the PZC values and variations of the textural properties. Under ultraviolet (UV) irradiation, the C–N, C–S, and N[dbnd]N bonds linking with different functional groups in CR structure can be attacked by surface active species and interacted with the Fe3+/Fe2+, Cu2+/Cu+ and V5+/V4+ couples, leading to breaking of the CR molecular structure into various intermediate species. The photo-enhanced chemical reaction cycles were discussed and the CR photodegradation mechanisms was presented.

Original languageEnglish
JournalCatalysis Today
DOIs
StateAccepted/In press - 1 Jan 2018

Fingerprint

Congo Red
Multicarrier modulation
Oxides
Transition metals
Degradation
Catalysts
Metals
Ions
Spectroscopic analysis
Photodegradation
Band structure
Functional groups
Molecular structure
MCM-41
Chemical reactions
Optical properties
Irradiation
Crystalline materials
Oxidation

Keywords

  • Heterojuction structure
  • Mesoporous catalysts
  • Photodegradation
  • Ti-MCM-41

Cite this

Arellano, U. ; Wang, J. A. ; Chen, L. F. ; Asomoza, M. ; Guzmán, A. ; Solís, S. ; Estrella, A. ; Cipagauta, S. ; Noreña, L. E. / Transition metal oxides dispersed on Ti-MCM-41 hybrid core-shell catalysts for the photocatalytic degradation of Congo red colorant. In: Catalysis Today. 2018.
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abstract = "Hybrid core-shell catalysts were synthesized by transition metal (Fe, V and Cu) oxides dispersed on Ti doped mesoporous Ti-MCM-41 (noted as TiM) and their crystalline structures, morphologies, metal oxidation states and optical properties were studied with a variety of characterization techniques. All the catalysts showed a core-shell morphological feature. Fe2O3, CuO and V2O5 enriched the catalyst surface forming an oxide shell on the Ti-MCM-41 core. Predominant Fe3+, Cu2+ and V5+ ions coexisted with a small part of Fe2+, Cu+ and V4+ ions generating Fe3+/Fe2+, Cu2+/Cu+ and V5+/V4+ couples in the corresponding catalyst. The UV–vis spectroscopic analysis showed a shift of the prohibited band energy towards the visible region after the metal oxides loading. In the photocatalytic degradation reaction of Congo red (CR) in an aqueous solution, the catalysts exhibited an activity order as: Cu/TiM > Fe/TiM > V/TiM > TiM. The photocatalytic activity resulted from the affinity of the anionic colorant with the positively charged surface of the catalysts and correlated well with the PZC values and variations of the textural properties. Under ultraviolet (UV) irradiation, the C–N, C–S, and N[dbnd]N bonds linking with different functional groups in CR structure can be attacked by surface active species and interacted with the Fe3+/Fe2+, Cu2+/Cu+ and V5+/V4+ couples, leading to breaking of the CR molecular structure into various intermediate species. The photo-enhanced chemical reaction cycles were discussed and the CR photodegradation mechanisms was presented.",
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Transition metal oxides dispersed on Ti-MCM-41 hybrid core-shell catalysts for the photocatalytic degradation of Congo red colorant. / Arellano, U.; Wang, J. A.; Chen, L. F.; Asomoza, M.; Guzmán, A.; Solís, S.; Estrella, A.; Cipagauta, S.; Noreña, L. E.

In: Catalysis Today, 01.01.2018.

Research output: Contribution to journalArticle

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AU - Wang, J. A.

AU - Chen, L. F.

AU - Asomoza, M.

AU - Guzmán, A.

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AU - Estrella, A.

AU - Cipagauta, S.

AU - Noreña, L. E.

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N2 - Hybrid core-shell catalysts were synthesized by transition metal (Fe, V and Cu) oxides dispersed on Ti doped mesoporous Ti-MCM-41 (noted as TiM) and their crystalline structures, morphologies, metal oxidation states and optical properties were studied with a variety of characterization techniques. All the catalysts showed a core-shell morphological feature. Fe2O3, CuO and V2O5 enriched the catalyst surface forming an oxide shell on the Ti-MCM-41 core. Predominant Fe3+, Cu2+ and V5+ ions coexisted with a small part of Fe2+, Cu+ and V4+ ions generating Fe3+/Fe2+, Cu2+/Cu+ and V5+/V4+ couples in the corresponding catalyst. The UV–vis spectroscopic analysis showed a shift of the prohibited band energy towards the visible region after the metal oxides loading. In the photocatalytic degradation reaction of Congo red (CR) in an aqueous solution, the catalysts exhibited an activity order as: Cu/TiM > Fe/TiM > V/TiM > TiM. The photocatalytic activity resulted from the affinity of the anionic colorant with the positively charged surface of the catalysts and correlated well with the PZC values and variations of the textural properties. Under ultraviolet (UV) irradiation, the C–N, C–S, and N[dbnd]N bonds linking with different functional groups in CR structure can be attacked by surface active species and interacted with the Fe3+/Fe2+, Cu2+/Cu+ and V5+/V4+ couples, leading to breaking of the CR molecular structure into various intermediate species. The photo-enhanced chemical reaction cycles were discussed and the CR photodegradation mechanisms was presented.

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