Role of water and carbonates in photocatalytic transformation of CO2 to CH4 on titania

Nada M Dimitrijevic; Baiju K Vijayan; Oleg G Poluektov; Tijana Rajh; Kimberly A Gray; Haiying He; Peter Zapol

doi:10.1021/ja108791u

Role of water and carbonates in photocatalytic transformation of CO2 to CH4 on titania

J Am Chem Soc. 2011 Mar 23;133(11):3964-71. doi: 10.1021/ja108791u. Epub 2011 Feb 24.

Authors

Nada M Dimitrijevic¹, Baiju K Vijayan, Oleg G Poluektov, Tijana Rajh, Kimberly A Gray, Haiying He, Peter Zapol

Affiliation

¹ Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States. dimitrijevic@anl.gov

PMID: 21348527
DOI: 10.1021/ja108791u

Abstract

Using the electron paramagnetic resonance technique, we have elucidated the multiple roles of water and carbonates in the overall photocatalytic reduction of carbon dioxide to methane over titania nanoparticles. The formation of H atoms (reduction product) and (•)OH radicals (oxidation product) from water, and CO(3)(-) radical anions (oxidation product) from carbonates, was detected in CO(2)-saturated titania aqueous dispersion under UV illumination. Additionally, methoxyl, (•)OCH(3), and methyl, (•)CH(3), radicals were identified as reaction intermediates. The two-electron, one-proton reaction proposed as an initial step in the reduction of CO(2) on the surface of TiO(2) is supported by the results of first-principles calculations.