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Photocatalytic reduction of CO2 with H2O on mesoporous silica supported Cu/TiO2 catalysts

Paper ID Volume ID Publish Year Pages File Format Full-Text
47181 46462 2010 7 PDF Available
Title
Photocatalytic reduction of CO2 with H2O on mesoporous silica supported Cu/TiO2 catalysts
Abstract

Photoreduction of CO2 to hydrocarbons is a sustainable energy technology which not only mitigates emissions but also provides alternative fuels. However, one of the largest challenges is to increase the overall CO2 photo-conversion efficiency when water is used as the reducing reagent. In this work, mesoporous silica supported Cu/TiO2 nanocomposites were synthesized through a one-pot sol–gel method, and the photoreduction experiments were carried out in a continuous-flow reactor using CO2 and water vapor as the reactants under the irradiation of a Xe lamp. The high surface area mesoporous silica substrate (>300 m2/g) greatly enhanced CO2 photoreduction, possibly due to improved TiO2 dispersion and increased adsorption of CO2 and H2O on the catalyst. CO was found to be the primary product of CO2 reduction for TiO2–SiO2 catalysts without Cu. The addition of Cu species, which was identified to be Cu2O by the XPS, markedly increased the overall CO2 conversion efficiency as well as the selectivity to CH4, by suppressing the electron–hole recombination and enhancing multi-electron reactions. A synergistic effect was observed by combining the porous SiO2 support and the deposition of Cu on TiO2. The peak production rates of CO and CH4 reached 60 and 10 μmol g-cat−1 h−1, respectively, for the 0.5%Cu/TiO2–SiO2 composite that has the optimum Cu concentration; the peak quantum yield was calculated to be 1.41%. Deactivation and regeneration of the catalyst was observed and the mechanism was discussed. Desorption of the reaction intermediates from the active sites may be the rate limiting step.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights▶ CO2 is photocatalytically reduced with water vapor on Cu/TiO2–SiO2 nanocomposites. ▶ CO and CH4 are the primary products of CO2 photoreduction. ▶ SiO2 support and Cu deposition on TiO2 synergistically enhance CO2 reduction rate. ▶ Selectivity of CH4 production is enhanced with Cu deposition. ▶ Cu(I) species are active sites of electron traps.

Keywords
Photocatalysis; TiO2; Nanocomposite; CO2 photoreduction
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Photocatalytic reduction of CO2 with H2O on mesoporous silica supported Cu/TiO2 catalysts
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 100, Issues 1–2, 11 October 2010, Pages 386–392
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us