TY - JOUR

T1 - Pathways of the photocatalytic reaction of acetate in H2O and D2O

T2 - A combined EPR and ATR-FTIR study

AU - Belhadj, H.

AU - Melchers, S.

AU - Robertson, P.K.J.

AU - Bahnemann, D.W.

N1 - Funding information: Belhadj H. gratefully acknowledges a scholarship from the Deutscher Akademischer Austauschdienst (DAAD) providing the financial support to perform his Ph.D. studies in Germany. The present study was performed within the Project “Establishment of the Laboratory ‘Photoactive Nanocomposite Materials’” No. 14.Z50.31.0016 supported by a Mega-grant of the Government of the Russian Federation . This work was partially funded by the German Federal Ministry of Education and Research (contract no. 13N13350, PureBau – Untersuchung von Werkstoffsystemen für photokatalytisch hocheffiziente Baustoffe-Teilvorhaben: Oberflächenchemie der Photokatalysatoren und der Werkstoffe).

PY - 2016/12

Y1 - 2016/12

N2 - The adsorption and photocatalytic degradation of acetate on TiO 2 surfaces were investigated in H 2O and D 2O by ATR-FTIR and EPR Spectroscopy respectively. These studies were carried out in the dark and under UV(A) illumination to gain additional insights into the adsorption behaviour with the identification of paramagnetic species formed during the oxidation of acetate. Isotopic exchange during the adsorption of D 2O on the TiO 2 surface led to different interactions between the adsorbate and OD groups. At different pH levels, several surface complexes of acetate can be formed such as monodentates or bidentates. Under UV(A) irradiation of TiO 2 aqueous suspensions, the formation of hydroxyl and methoxy radicals evidenced as the corresponding spin-adducts, was found to dominate in alkaline and acidic suspensions respectively. Two possible pathways for the oxidation of acetate have been suggested at different pH levels in solution in terms of the source of the spin adduct formed. These proposed pathways were found to be in good agreement with ATR-FTIR and EPR results.

AB - The adsorption and photocatalytic degradation of acetate on TiO 2 surfaces were investigated in H 2O and D 2O by ATR-FTIR and EPR Spectroscopy respectively. These studies were carried out in the dark and under UV(A) illumination to gain additional insights into the adsorption behaviour with the identification of paramagnetic species formed during the oxidation of acetate. Isotopic exchange during the adsorption of D 2O on the TiO 2 surface led to different interactions between the adsorbate and OD groups. At different pH levels, several surface complexes of acetate can be formed such as monodentates or bidentates. Under UV(A) irradiation of TiO 2 aqueous suspensions, the formation of hydroxyl and methoxy radicals evidenced as the corresponding spin-adducts, was found to dominate in alkaline and acidic suspensions respectively. Two possible pathways for the oxidation of acetate have been suggested at different pH levels in solution in terms of the source of the spin adduct formed. These proposed pathways were found to be in good agreement with ATR-FTIR and EPR results.

KW - Acetate

KW - Adsorption

KW - D O

KW - EPR spin trapping

KW - In situ ATR-FTIR

KW - Photocatalysis

KW - TiO

KW - pH

UR - http://www.scopus.com/inward/record.url?scp=85000607315&partnerID=8YFLogxK

U2 - 10.1016/j.jcat.2016.08.006

DO - 10.1016/j.jcat.2016.08.006

M3 - Article

VL - 344

JO - Journal of catalysis

JF - Journal of catalysis

SN - 0021-9517

ER -