TY - JOUR
T1 - Supported titanium oxide species as photocatalysts in 2-propanol oxidation
T2 - Linking selectivity to structural and electronic properties
AU - Lang, Moritz
AU - Klahn, Marcus
AU - Strunk, Jennifer
N1 - Publisher Copyright:
© 2022
PY - 2023/2/15
Y1 - 2023/2/15
N2 - The photocatalytic performance of titanium oxide species supported on mesoporous silica (SBA-15) in the selective oxidation of 2-propanol is studied systematically as function of the titania surface loading. Monomers and oligomers of the supported titanium oxide species are formed on the silica surface in differing amounts with increasing loading, and the photocatalytic activity shows a strong dependence on the titanium content. A general advantage of supported samples in terms of net productivity could not be observed, but the photocatalysts’ longevity and selectivity improve with lower degrees of oligomerization. In-situ infrared spectroscopy in diffuse reflectance under irradiation revealed a likely explanation for this observation: The relative probability of the overoxidation of 2-propanol to acetate and possibly even total oxidation to CO2 increases with loading and is most severe for crystalline bulk titania. Stably adsorbed acetate appears to block the active sites on crystalline TiO2, but it is tolerable to a certain extent for the silica-supported samples. This work provides fundamental knowledge for the development of more stable and selective oxidation photocatalysts.
AB - The photocatalytic performance of titanium oxide species supported on mesoporous silica (SBA-15) in the selective oxidation of 2-propanol is studied systematically as function of the titania surface loading. Monomers and oligomers of the supported titanium oxide species are formed on the silica surface in differing amounts with increasing loading, and the photocatalytic activity shows a strong dependence on the titanium content. A general advantage of supported samples in terms of net productivity could not be observed, but the photocatalysts’ longevity and selectivity improve with lower degrees of oligomerization. In-situ infrared spectroscopy in diffuse reflectance under irradiation revealed a likely explanation for this observation: The relative probability of the overoxidation of 2-propanol to acetate and possibly even total oxidation to CO2 increases with loading and is most severe for crystalline bulk titania. Stably adsorbed acetate appears to block the active sites on crystalline TiO2, but it is tolerable to a certain extent for the silica-supported samples. This work provides fundamental knowledge for the development of more stable and selective oxidation photocatalysts.
KW - DRIFTS
KW - Heterogeneous photocatalysis
KW - Selective oxidation
KW - Single-site catalysts
KW - TiO
UR - http://www.scopus.com/inward/record.url?scp=85141928357&partnerID=8YFLogxK
U2 - 10.1016/j.apsusc.2022.155623
DO - 10.1016/j.apsusc.2022.155623
M3 - Article
AN - SCOPUS:85141928357
SN - 0169-4332
VL - 611
JO - Applied Surface Science
JF - Applied Surface Science
M1 - 155623
ER -