Mechanistic and adsorption studies of relevance to photocatalysts on titanium grafted mesoporous silicalites

Alon Danon; Peter C. Stair; Eric Weitz

doi:10.1007/s10562-011-0644-9

Mechanistic and adsorption studies of relevance to photocatalysts on titanium grafted mesoporous silicalites

Alon Danon, Peter C. Stair, Eric Weitz

Northwestern University

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

8 Citations (Scopus)

Abstract

Ti-SBA-15 and Ti-MCM-41 were synthesized and evaluated as possible photocatalysts for the reduction of CO₂, and for the photo-Kolbe decomposition of acetic acid. UV-Raman was used to study the adsorption of carbon dioxide, water, formic acid, and acetic acid over Ti-MCM-41 by monitoring the UV enhanced resonance peak of the totally symmetric stretching band of the grafted Ti species at 1,085 cm^-1. Acetic and formic acid dissociate on Ti-SBA-15 and Ti-MCM-41 to form acetate and formate, respectively. The conjugate bases subsequently interact strongly with Ti sites. Water interacts with the Ti sites, while no change in the amplitude of the 1,085 cm^-1 band is observed in the presence of CO₂. Photocatalysis experiments indicate that these mesoporous silicalites are active in the photo-Kolbe decomposition of acetic acid. CO₂ is formed by reaction of a hole with the acetate carboxylate groups. The methyl radical co-products react with a surface proton and an electron to form methane. No products resulting from the dimerization of methyl radicals are observed, presumably because of the highly dispersed active sites.

Original language	English
Pages (from-to)	1057-1066
Number of pages	10
Journal	Catalysis Letters
Volume	141
Issue number	8
DOIs	https://doi.org/10.1007/s10562-011-0644-9
Publication status	Published - Aug 2011

Keywords

Mesoporous silicalites
Photo-decomposition
Photocatalysis
Ti-MCM-41
Ti-SBA-15
Titanium grafted

ASJC Scopus subject areas

Catalysis
Chemistry(all)

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@article{847c20186e2e470b87a0b7adef90dcb3,

title = "Mechanistic and adsorption studies of relevance to photocatalysts on titanium grafted mesoporous silicalites",

abstract = "Ti-SBA-15 and Ti-MCM-41 were synthesized and evaluated as possible photocatalysts for the reduction of CO2, and for the photo-Kolbe decomposition of acetic acid. UV-Raman was used to study the adsorption of carbon dioxide, water, formic acid, and acetic acid over Ti-MCM-41 by monitoring the UV enhanced resonance peak of the totally symmetric stretching band of the grafted Ti species at 1,085 cm-1. Acetic and formic acid dissociate on Ti-SBA-15 and Ti-MCM-41 to form acetate and formate, respectively. The conjugate bases subsequently interact strongly with Ti sites. Water interacts with the Ti sites, while no change in the amplitude of the 1,085 cm-1 band is observed in the presence of CO2. Photocatalysis experiments indicate that these mesoporous silicalites are active in the photo-Kolbe decomposition of acetic acid. CO2 is formed by reaction of a hole with the acetate carboxylate groups. The methyl radical co-products react with a surface proton and an electron to form methane. No products resulting from the dimerization of methyl radicals are observed, presumably because of the highly dispersed active sites.",

keywords = "Mesoporous silicalites, Photo-decomposition, Photocatalysis, Ti-MCM-41, Ti-SBA-15, Titanium grafted",

author = "Alon Danon and Stair, {Peter C.} and Eric Weitz",

note = "Funding Information: Acknowledgments This work was supported by the Chemical Sciences, Geosciences and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy (Award DE-FG02-03-ER15457). This work made use of the J. B. Cohen X-ray Diffraction Facility supported by the MRSEC program of the National Science Foundation (DMR-0520513) at the Materials Research Center of Northwestern University. The electron imaging and diffraction work was performed in the EPIC facility of NUANCE Center at Northwestern University. NUANCE Center is supported by NSF-NSEC, NSF-MRSEC, Keck Foundation, the State of Illinois, and Northwestern University.",

year = "2011",

month = aug,

doi = "10.1007/s10562-011-0644-9",

language = "English",

volume = "141",

pages = "1057--1066",

journal = "Catalysis Letters",

issn = "1011-372X",

publisher = "Springer Netherlands",

number = "8",

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T1 - Mechanistic and adsorption studies of relevance to photocatalysts on titanium grafted mesoporous silicalites

AU - Danon, Alon

AU - Stair, Peter C.

AU - Weitz, Eric

N1 - Funding Information: Acknowledgments This work was supported by the Chemical Sciences, Geosciences and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy (Award DE-FG02-03-ER15457). This work made use of the J. B. Cohen X-ray Diffraction Facility supported by the MRSEC program of the National Science Foundation (DMR-0520513) at the Materials Research Center of Northwestern University. The electron imaging and diffraction work was performed in the EPIC facility of NUANCE Center at Northwestern University. NUANCE Center is supported by NSF-NSEC, NSF-MRSEC, Keck Foundation, the State of Illinois, and Northwestern University.

PY - 2011/8

Y1 - 2011/8

N2 - Ti-SBA-15 and Ti-MCM-41 were synthesized and evaluated as possible photocatalysts for the reduction of CO2, and for the photo-Kolbe decomposition of acetic acid. UV-Raman was used to study the adsorption of carbon dioxide, water, formic acid, and acetic acid over Ti-MCM-41 by monitoring the UV enhanced resonance peak of the totally symmetric stretching band of the grafted Ti species at 1,085 cm-1. Acetic and formic acid dissociate on Ti-SBA-15 and Ti-MCM-41 to form acetate and formate, respectively. The conjugate bases subsequently interact strongly with Ti sites. Water interacts with the Ti sites, while no change in the amplitude of the 1,085 cm-1 band is observed in the presence of CO2. Photocatalysis experiments indicate that these mesoporous silicalites are active in the photo-Kolbe decomposition of acetic acid. CO2 is formed by reaction of a hole with the acetate carboxylate groups. The methyl radical co-products react with a surface proton and an electron to form methane. No products resulting from the dimerization of methyl radicals are observed, presumably because of the highly dispersed active sites.

AB - Ti-SBA-15 and Ti-MCM-41 were synthesized and evaluated as possible photocatalysts for the reduction of CO2, and for the photo-Kolbe decomposition of acetic acid. UV-Raman was used to study the adsorption of carbon dioxide, water, formic acid, and acetic acid over Ti-MCM-41 by monitoring the UV enhanced resonance peak of the totally symmetric stretching band of the grafted Ti species at 1,085 cm-1. Acetic and formic acid dissociate on Ti-SBA-15 and Ti-MCM-41 to form acetate and formate, respectively. The conjugate bases subsequently interact strongly with Ti sites. Water interacts with the Ti sites, while no change in the amplitude of the 1,085 cm-1 band is observed in the presence of CO2. Photocatalysis experiments indicate that these mesoporous silicalites are active in the photo-Kolbe decomposition of acetic acid. CO2 is formed by reaction of a hole with the acetate carboxylate groups. The methyl radical co-products react with a surface proton and an electron to form methane. No products resulting from the dimerization of methyl radicals are observed, presumably because of the highly dispersed active sites.

KW - Mesoporous silicalites

KW - Photo-decomposition

KW - Photocatalysis

KW - Ti-MCM-41

KW - Ti-SBA-15

KW - Titanium grafted

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EP - 1066

JO - Catalysis Letters

JF - Catalysis Letters

SN - 1011-372X

IS - 8

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