A comparison of mixed phase titania photocatalysts prepared by physical and chemical methods: The importance of the solid-solid interface

Gonghu Li; Le Chen; Michael E. Graham; Kimberly A. Gray

doi:10.1016/j.molcata.2007.05.017

A comparison of mixed phase titania photocatalysts prepared by physical and chemical methods: The importance of the solid-solid interface

Gonghu Li, Le Chen, Michael E. Graham, Kimberly A. Gray^*

^*Corresponding author for this work

Civil and Environmental Engineering

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

138 Scopus citations

Abstract

Mixed phase titania photocatalysts, such as Degussa P25, typically show higher photocatalytic activity than pure phase titania, as reported by many researchers. Our previous experimental results indicate that the solid-solid interface is a key factor in enhancing the photocatalytic reactivity of mixed phase titania and may be the location of catalytic "hot spots". In this study, titania photocatalysts consisting of varying amount of anatase and rutile phases are prepared by reactive dc magnetron sputtering and by a modified sol-gel method. These titania materials are characterized with a variety of techniques and are tested in the photocatalytic degradation of acetaldehyde. Mixed phase titania thin films prepared by magnetron sputtering have a high density of anatase-rutile interfaces and display the highest photocatalytic activity among the catalysts tested. Studies by electron paramagnetic resonance spectroscopy show a unique distribution of charge trapping sites which are characteristic of the sputtered films. The role of anatase-rutile interface to separate charge and improve the photoactivity of mixed phase materials is discussed.

Original language	English (US)
Pages (from-to)	30-35
Number of pages	6
Journal	Journal of Molecular Catalysis A: Chemical
Volume	275
Issue number	1-2
DOIs	https://doi.org/10.1016/j.molcata.2007.05.017
State	Published - Sep 17 2007

Funding

The authors thank Dr. Zoran Saponjic, Dr. Nada Dimitrijevic, and Dr. Tijana Rajh of Argonne National Laboratory for their kind assistance on EPR spectroscopy. Funding from the US Department of Energy (DE-FG02-03ER15457/A003 and 5F-00546/W-31-109-ENG38) and the National Science Foundation (CHE-9810378) and the generous donation of Degussa P25 by Degussa are greatly appreciated. Dr. Gonghu Li was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences, under contract DE-AC02-06CH11357. The characterization (XRD and SEM) was performed in the MRSEC and NUANCE center at Northwestern University.

Keywords

Magnetron sputtering
Photocatalysis
Sol-gel
Titania

ASJC Scopus subject areas

Catalysis
Process Chemistry and Technology
Physical and Theoretical Chemistry

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10.1016/j.molcata.2007.05.017

Cite this

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title = "A comparison of mixed phase titania photocatalysts prepared by physical and chemical methods: The importance of the solid-solid interface",

abstract = "Mixed phase titania photocatalysts, such as Degussa P25, typically show higher photocatalytic activity than pure phase titania, as reported by many researchers. Our previous experimental results indicate that the solid-solid interface is a key factor in enhancing the photocatalytic reactivity of mixed phase titania and may be the location of catalytic {"}hot spots{"}. In this study, titania photocatalysts consisting of varying amount of anatase and rutile phases are prepared by reactive dc magnetron sputtering and by a modified sol-gel method. These titania materials are characterized with a variety of techniques and are tested in the photocatalytic degradation of acetaldehyde. Mixed phase titania thin films prepared by magnetron sputtering have a high density of anatase-rutile interfaces and display the highest photocatalytic activity among the catalysts tested. Studies by electron paramagnetic resonance spectroscopy show a unique distribution of charge trapping sites which are characteristic of the sputtered films. The role of anatase-rutile interface to separate charge and improve the photoactivity of mixed phase materials is discussed.",

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AB - Mixed phase titania photocatalysts, such as Degussa P25, typically show higher photocatalytic activity than pure phase titania, as reported by many researchers. Our previous experimental results indicate that the solid-solid interface is a key factor in enhancing the photocatalytic reactivity of mixed phase titania and may be the location of catalytic "hot spots". In this study, titania photocatalysts consisting of varying amount of anatase and rutile phases are prepared by reactive dc magnetron sputtering and by a modified sol-gel method. These titania materials are characterized with a variety of techniques and are tested in the photocatalytic degradation of acetaldehyde. Mixed phase titania thin films prepared by magnetron sputtering have a high density of anatase-rutile interfaces and display the highest photocatalytic activity among the catalysts tested. Studies by electron paramagnetic resonance spectroscopy show a unique distribution of charge trapping sites which are characteristic of the sputtered films. The role of anatase-rutile interface to separate charge and improve the photoactivity of mixed phase materials is discussed.

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A comparison of mixed phase titania photocatalysts prepared by physical and chemical methods: The importance of the solid-solid interface

Abstract

Funding

Keywords

ASJC Scopus subject areas

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