Effect of the support on the photocatalytic water oxidation activity of cobalt oxide nanoclusters

Seif Yusuf; Feng Jiao

doi:10.1021/cs300581k

Effect of the support on the photocatalytic water oxidation activity of cobalt oxide nanoclusters

Seif Yusuf, Feng Jiao

Department of Energy, Environmental & Chemical Engineering

Research output: Contribution to journal › Article › peer-review

97 Scopus citations

Abstract

Oxygen evolution from water driven by visible light is one of the key reactions for solar fuel production. In this paper, we investigated the effect of the support on photocatalytic water oxidation under visible light using cobalt oxide as a multielectron catalyst. A range of supported Co ₃O₄ nanoclusters have been successfully synthesized via wet impregnation and bisolvent methods. Compared with the wet impregnation approach, the bisolvent method allowed us to obtain a high quality catalyst with all the Co₃O₄ nanoclusters formed inside the mesoporous support using hexane/water as the combination. The resulting catalyst consists of Co₃O₄ nanoclusters with a very small particle size (∼25 nm) and narrow size distribution. Catalytic water oxidation experiments were performed in [Ru(bpy)₃]²⁺-persulfate (photochemical) and Ce⁴⁺/Ce³⁺ (chemical) systems, and it was found that smaller Co₃O₄ cluster sizes resulted in higher water oxidation activity. In addition, KIT-6 was found to be a better support than SBA-15, which is likely due to the fact that the 3D porous structure of KIT-6 offers more accessible pores than the 1D channels in SBA-15. To further elucidate the role of support in the photocatalytic oxygen evolution, bare Co₃O₄ nanoparticles together with two SiO₂- and γ-Al₂O₃-supported ones were investigated. Photocatalytic studies show that both supported Co₃O₄ nanoparticles exhibited significant enhancement (50-80%) in oxygen evolution activity, compared with bare Co₃O₄ nanoparticles. However, switching from the SiO₂ to γ-Al₂O₃ support does not significantly change the activities, indicating composition and surface properties of the support do not participate in rate-limiting steps in oxygen evolution. It can be concluded that the major role of catalyst supports in Co₃O₄-based water oxidation catalysts is to provide a medium to physically separate Co₃O₄ nanoclusters from aggregation, leading to superior photocatalytic activities.

Original language	English
Pages (from-to)	2753-2760
Number of pages	8
Journal	ACS Catalysis
Volume	2
Issue number	12
DOIs	https://doi.org/10.1021/cs300581k
State	Published - Dec 7 2012

Keywords

cobalt oxide
oxygen evolution
photocatalysis
support effect
water oxidation

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10.1021/cs300581k

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title = "Effect of the support on the photocatalytic water oxidation activity of cobalt oxide nanoclusters",

abstract = "Oxygen evolution from water driven by visible light is one of the key reactions for solar fuel production. In this paper, we investigated the effect of the support on photocatalytic water oxidation under visible light using cobalt oxide as a multielectron catalyst. A range of supported Co 3O4 nanoclusters have been successfully synthesized via wet impregnation and bisolvent methods. Compared with the wet impregnation approach, the bisolvent method allowed us to obtain a high quality catalyst with all the Co3O4 nanoclusters formed inside the mesoporous support using hexane/water as the combination. The resulting catalyst consists of Co3O4 nanoclusters with a very small particle size (∼25 nm) and narrow size distribution. Catalytic water oxidation experiments were performed in [Ru(bpy)3]2+-persulfate (photochemical) and Ce4+/Ce3+ (chemical) systems, and it was found that smaller Co3O4 cluster sizes resulted in higher water oxidation activity. In addition, KIT-6 was found to be a better support than SBA-15, which is likely due to the fact that the 3D porous structure of KIT-6 offers more accessible pores than the 1D channels in SBA-15. To further elucidate the role of support in the photocatalytic oxygen evolution, bare Co3O4 nanoparticles together with two SiO2- and γ-Al2O3-supported ones were investigated. Photocatalytic studies show that both supported Co3O4 nanoparticles exhibited significant enhancement (50-80\%) in oxygen evolution activity, compared with bare Co3O4 nanoparticles. However, switching from the SiO2 to γ-Al2O3 support does not significantly change the activities, indicating composition and surface properties of the support do not participate in rate-limiting steps in oxygen evolution. It can be concluded that the major role of catalyst supports in Co3O4-based water oxidation catalysts is to provide a medium to physically separate Co3O4 nanoclusters from aggregation, leading to superior photocatalytic activities.",

keywords = "cobalt oxide, oxygen evolution, photocatalysis, support effect, water oxidation",

author = "Seif Yusuf and Feng Jiao",

year = "2012",

month = dec,

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doi = "10.1021/cs300581k",

language = "English",

volume = "2",

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journal = "ACS Catalysis",

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TY - JOUR

T1 - Effect of the support on the photocatalytic water oxidation activity of cobalt oxide nanoclusters

AU - Yusuf, Seif

AU - Jiao, Feng

PY - 2012/12/7

Y1 - 2012/12/7

N2 - Oxygen evolution from water driven by visible light is one of the key reactions for solar fuel production. In this paper, we investigated the effect of the support on photocatalytic water oxidation under visible light using cobalt oxide as a multielectron catalyst. A range of supported Co 3O4 nanoclusters have been successfully synthesized via wet impregnation and bisolvent methods. Compared with the wet impregnation approach, the bisolvent method allowed us to obtain a high quality catalyst with all the Co3O4 nanoclusters formed inside the mesoporous support using hexane/water as the combination. The resulting catalyst consists of Co3O4 nanoclusters with a very small particle size (∼25 nm) and narrow size distribution. Catalytic water oxidation experiments were performed in [Ru(bpy)3]2+-persulfate (photochemical) and Ce4+/Ce3+ (chemical) systems, and it was found that smaller Co3O4 cluster sizes resulted in higher water oxidation activity. In addition, KIT-6 was found to be a better support than SBA-15, which is likely due to the fact that the 3D porous structure of KIT-6 offers more accessible pores than the 1D channels in SBA-15. To further elucidate the role of support in the photocatalytic oxygen evolution, bare Co3O4 nanoparticles together with two SiO2- and γ-Al2O3-supported ones were investigated. Photocatalytic studies show that both supported Co3O4 nanoparticles exhibited significant enhancement (50-80%) in oxygen evolution activity, compared with bare Co3O4 nanoparticles. However, switching from the SiO2 to γ-Al2O3 support does not significantly change the activities, indicating composition and surface properties of the support do not participate in rate-limiting steps in oxygen evolution. It can be concluded that the major role of catalyst supports in Co3O4-based water oxidation catalysts is to provide a medium to physically separate Co3O4 nanoclusters from aggregation, leading to superior photocatalytic activities.

AB - Oxygen evolution from water driven by visible light is one of the key reactions for solar fuel production. In this paper, we investigated the effect of the support on photocatalytic water oxidation under visible light using cobalt oxide as a multielectron catalyst. A range of supported Co 3O4 nanoclusters have been successfully synthesized via wet impregnation and bisolvent methods. Compared with the wet impregnation approach, the bisolvent method allowed us to obtain a high quality catalyst with all the Co3O4 nanoclusters formed inside the mesoporous support using hexane/water as the combination. The resulting catalyst consists of Co3O4 nanoclusters with a very small particle size (∼25 nm) and narrow size distribution. Catalytic water oxidation experiments were performed in [Ru(bpy)3]2+-persulfate (photochemical) and Ce4+/Ce3+ (chemical) systems, and it was found that smaller Co3O4 cluster sizes resulted in higher water oxidation activity. In addition, KIT-6 was found to be a better support than SBA-15, which is likely due to the fact that the 3D porous structure of KIT-6 offers more accessible pores than the 1D channels in SBA-15. To further elucidate the role of support in the photocatalytic oxygen evolution, bare Co3O4 nanoparticles together with two SiO2- and γ-Al2O3-supported ones were investigated. Photocatalytic studies show that both supported Co3O4 nanoparticles exhibited significant enhancement (50-80%) in oxygen evolution activity, compared with bare Co3O4 nanoparticles. However, switching from the SiO2 to γ-Al2O3 support does not significantly change the activities, indicating composition and surface properties of the support do not participate in rate-limiting steps in oxygen evolution. It can be concluded that the major role of catalyst supports in Co3O4-based water oxidation catalysts is to provide a medium to physically separate Co3O4 nanoclusters from aggregation, leading to superior photocatalytic activities.

KW - cobalt oxide

KW - oxygen evolution

KW - photocatalysis

KW - support effect

KW - water oxidation

UR - https://www.scopus.com/pages/publications/84870937100

U2 - 10.1021/cs300581k

DO - 10.1021/cs300581k

M3 - Article

AN - SCOPUS:84870937100

SN - 2155-5435

VL - 2

SP - 2753

EP - 2760

JO - ACS Catalysis

JF - ACS Catalysis

IS - 12

ER -

Effect of the support on the photocatalytic water oxidation activity of cobalt oxide nanoclusters

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Keywords

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