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Indian Journal of Chemistry -Section A (IJC-A) >
IJC-A Vol.51A [2012] >
IJC-A Vol.51A(03) [March 2012] >
| Title: | Photocatalytic reduction of carbon dioxide by water on titania: Role of photophysical and structural properties |
| Authors: | Rajalakshmi, K
Jeyalakshmi, V
Krishnamurthy, K R
Viswanathan, B |
| Keywords: | Photocatalytic Reduction
Photophysical Properties
Titania
Carbon Dioxide Reduction
Structural Properties |
| Issue Date: | Mar-2012 |
| Publisher: | NISCAIR-CSIR, India |
| Abstract: | Photocatalytic reduction of carbon dioxide has been
investigated on three different titania catalysts (two commercial titania, De
Gussa P-25 and UV-100 Hombikat and another catalyst prepared by sol-gel method
under reverse micelle environment) dispersed in aqueous alkaline medium under
irradiation in visible region (300-700 nm) from Hg lamp. The catalysts have
been characterized by XRD, diffuse reflectance and fluorescence spectroscopic
techniques and textural analysis. Methane, methanol and ethanol are observed as
the major products. Activity in terms of total hydrocarbons production and
(methane + methanol) yields during six hours run follows the order: P-25>RM-TiO2>UV-100.
Ethanol is formed in significant amounts in the case of UV-100 and RM-TiO2
but not with P-25. Probable reaction pathways that lead to the formation of
these products have been proposed. While the catalytic activity is governed by
the generation and life span of photo-induced charge carriers, it is envisaged
that product selectivity is determined by the type of transformations that the
transient surface species undergo on titania. Surface Ti ions with singly or
doubly vacant coordination sites (four or five coordinate Ti ions) act as
active centres for these transformations. The relative population of four/five
coordinate Ti ions play a vital role in directing the transformations and hence
selectivity. The coordination environment of surface Ti atoms evolves during
catalyst preparation. Photophysical as well as structural properties of titania samples influence their overall
catalyst performance. |
| Page(s): | 411-419 |
| CC License: |  CC Attribution-Noncommercial-No Derivative Works 2.5 India |
| Source: | IJC-A Vol.51A(03) [March 2012]
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