Details
| Original language | English |
|---|---|
| Pages (from-to) | 81-90 |
| Number of pages | 10 |
| Journal | Journal of Photochemistry and Photobiology A: Chemistry |
| Volume | 366 |
| Early online date | 7 Apr 2018 |
| Publication status | Published - 1 Nov 2018 |
Abstract
The photocatalytic degradation of aqueous oxalic acid has been investigated employing different photocatalytic systems under constant pH conditions. A self-prepared TiO 2 was utilized during the photocatalytic investigations in a bare and a platinized form. The synthesized pure anatase phase TiO 2 had a 10 nm grain size and a BET surface area of ca. 121 m 2 g −1 with relatively higher photocatalytic activity compared to the commercially available TiO 2 photocatalyst UV100. Complete photocatalytic degradation of oxalic acid was observed within 60 min of illumination under aerobic condition with no by-product been detected. In the absence of molecular oxygen, a perceptible amount of formic acid was formed in the liquid phase, as determined quantitatively by means of ion chromatography. The formation of formic acid suggests that a photo-Kolbe reaction tacks place under oxygen-free conditions. The formation of formic acid was also noticed when platinized TiO 2 (0.25 wt.%) was employed, together with an enhancement of the reactions photonic efficiency to the quadruple. A hydrogen evolution could only observe under oxygen-free condition with, again, a higher formation rate over the platinized material. However, upon complete photoreforming of oxalic acid the overall amount of the photocatalytically evolved hydrogen using Pt 0.25%/TiO 2 represented only 60% of the theoretical amount. Therefore, it is suggested that the source of H atoms could be the HC 2O 4 − species rather than molecular oxalic acid. A detailed mechanism for the photocatalytic degradation of aqueous oxalic acid at different photocatalytic conditions is proposed and discussed.
Keywords
- Hydrogen evolution, Oxalic acid, Photocatalysis, Photocatalytic reforming, Solar fuel, TiO
ASJC Scopus subject areas
Cite this
- Standard
- Harvard
- Apa
- Vancouver
- BibTeX
- RIS
In: Journal of Photochemistry and Photobiology A: Chemistry, Vol. 366, 01.11.2018, p. 81-90.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Understanding the degradation pathways of oxalic acid in different photocatalytic systems
T2 - Towards simultaneous photocatalytic hydrogen evolution
AU - AlSalka, Y.
AU - Hakki, A.
AU - Fleisch, M.
AU - Bahnemann, D.W.
N1 - © 2018 Elsevier B.V. All rights reserved.
PY - 2018/11/1
Y1 - 2018/11/1
N2 - The photocatalytic degradation of aqueous oxalic acid has been investigated employing different photocatalytic systems under constant pH conditions. A self-prepared TiO 2 was utilized during the photocatalytic investigations in a bare and a platinized form. The synthesized pure anatase phase TiO 2 had a 10 nm grain size and a BET surface area of ca. 121 m 2 g −1 with relatively higher photocatalytic activity compared to the commercially available TiO 2 photocatalyst UV100. Complete photocatalytic degradation of oxalic acid was observed within 60 min of illumination under aerobic condition with no by-product been detected. In the absence of molecular oxygen, a perceptible amount of formic acid was formed in the liquid phase, as determined quantitatively by means of ion chromatography. The formation of formic acid suggests that a photo-Kolbe reaction tacks place under oxygen-free conditions. The formation of formic acid was also noticed when platinized TiO 2 (0.25 wt.%) was employed, together with an enhancement of the reactions photonic efficiency to the quadruple. A hydrogen evolution could only observe under oxygen-free condition with, again, a higher formation rate over the platinized material. However, upon complete photoreforming of oxalic acid the overall amount of the photocatalytically evolved hydrogen using Pt 0.25%/TiO 2 represented only 60% of the theoretical amount. Therefore, it is suggested that the source of H atoms could be the HC 2O 4 − species rather than molecular oxalic acid. A detailed mechanism for the photocatalytic degradation of aqueous oxalic acid at different photocatalytic conditions is proposed and discussed.
AB - The photocatalytic degradation of aqueous oxalic acid has been investigated employing different photocatalytic systems under constant pH conditions. A self-prepared TiO 2 was utilized during the photocatalytic investigations in a bare and a platinized form. The synthesized pure anatase phase TiO 2 had a 10 nm grain size and a BET surface area of ca. 121 m 2 g −1 with relatively higher photocatalytic activity compared to the commercially available TiO 2 photocatalyst UV100. Complete photocatalytic degradation of oxalic acid was observed within 60 min of illumination under aerobic condition with no by-product been detected. In the absence of molecular oxygen, a perceptible amount of formic acid was formed in the liquid phase, as determined quantitatively by means of ion chromatography. The formation of formic acid suggests that a photo-Kolbe reaction tacks place under oxygen-free conditions. The formation of formic acid was also noticed when platinized TiO 2 (0.25 wt.%) was employed, together with an enhancement of the reactions photonic efficiency to the quadruple. A hydrogen evolution could only observe under oxygen-free condition with, again, a higher formation rate over the platinized material. However, upon complete photoreforming of oxalic acid the overall amount of the photocatalytically evolved hydrogen using Pt 0.25%/TiO 2 represented only 60% of the theoretical amount. Therefore, it is suggested that the source of H atoms could be the HC 2O 4 − species rather than molecular oxalic acid. A detailed mechanism for the photocatalytic degradation of aqueous oxalic acid at different photocatalytic conditions is proposed and discussed.
KW - Hydrogen evolution
KW - Oxalic acid
KW - Photocatalysis
KW - Photocatalytic reforming
KW - Solar fuel
KW - TiO
UR - http://www.scopus.com/inward/record.url?scp=85045558842&partnerID=8YFLogxK
U2 - 10.1016/j.jphotochem.2018.04.008
DO - 10.1016/j.jphotochem.2018.04.008
M3 - Article
VL - 366
SP - 81
EP - 90
JO - Journal of Photochemistry and Photobiology A: Chemistry
JF - Journal of Photochemistry and Photobiology A: Chemistry
SN - 1010-6030
ER -