Photocatalytic degradation of ethylene: An FTIR in situ study under atmospheric conditions

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• 作者：Birger Hauchecorne^a ; ^{birger.hauchecorne@ua.ac.be"" rel=""nofollow} ; Tom Tytgat^a ; Sammy W. Verbruggen^a ; ^b ; Dieter Hauchecorne^c ; Dieter Terrens^a ; Marianne Smits^a ; Katrien Vinken^a ; Silvia Lenaerts^a
• 关键词：Photocatalysis ; Ethylene ; In situ FTIR study ; Reaction mechanism ; Molecular orbital theory
• 刊名：Applied Catalysis B: Environmental
• 出版年：2011
• 出版时间：9 June 2011
• 年：2011
• 卷：105
• 期：1-2
• 页码：111-116
• 全文大小：546 K

文摘

In this paper, the reaction mechanism of the photocatalytic oxidation of ethylene is elucidated by means of an in-house developed FTIR in situ reactor. This reactor allowed us to look at the catalytic surface at the moment the reactions actually occur. This new approach gave some exciting new insights in how ethylene is photocatalytically oxidised. It was found that there is a change in dipole moment of the ethylene molecule when it is brought in the neighbourhood of the catalyst. From this finding, a hypothesis was formulated on how the CC-bond from ethylene will break. It was found that the aforementioned interaction between the catalyst and the molecule, allows the excited electrons from the UV irradiated catalyst to occupy the lowest unoccupied molecular orbital (LUMO) of the ethylene molecule through a process known as backdonation. Following this hypothesis, it was found that the degradation occurs through the formation of two intermediates: formaldehyde and formic acid, for which formaldehyde is bound in two different ways (coordinatively and as bidentate). Finally CO₂ and H₂O are found as end products, resulting in the complete mineralisation of the pollutant.