Role of Water and Carbonates in Photocatalytic Transformation of CO2 to CH4 on Titania
Role of Water and Carbonates in Photocatalytic Transformation of CO2 to CH4 on Titania
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DOI：
10.1021/ja108791u
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发表时间：
2011-03-23
影响因子：
15
通讯作者：
Zapol, Peter
中科院分区：
文献类型：
--
作者：
Dimitrijevic, Nada M.;Vijayan, Baiju K.;Zapol, Peter
利用电子顺磁共振技术，我们阐明了水和碳酸盐在二氧化钛纳米颗粒上光催化还原二氧化碳为甲烷的多重作用。在紫外光照射下，测定了二氧化碳饱和的二氧化钛水分散体中水生成H原子（还原产物）和(OH)- o中心点自由基（氧化产物），碳酸盐生成CO3-自由基阴离子（氧化产物）。此外，甲氧基(OCH3)- o中心点和甲基(CH3)- c中心点自由基被确定为反应中间体。第一原理计算结果支持了作为TiO2表面CO2还原初始步骤的双电子、单质子反应。
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)-O-center dot radicals (oxidation product) from water, and CO3- radical anions (oxidation product) from carbonates, was detected in CO2-saturated titania aqueous dispersion under UV illumination. Additionally, methoxyl, (OCH3)-O-center dot, and methyl, (CH3)-C-center dot, radicals were identified as reaction intermediates. The two-electron, one-proton reaction proposed as an initial step in the reduction of CO2 on the surface of TiO2 is supported by the results of first-principles calculations.