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Title: CdTe quantum dot-functionalized P25 titania composite with enhanced photocatalytic NO2 storage selectivity under UV and vis irradiation
Authors: Leinen, Merve Balci
Dede, Didem
Khan, Munir Ullah
Çağlayan, Mustafa
Koçak, Yusuf
Demir, Hilmi Volkan
Ozensoy, Emrah
Keywords: Engineering::Electrical and electronic engineering
Issue Date: 2018
Source: Leinen, M. B., Dede, D., Khan, M. U., Çağlayan, M., Koçak, Y., Demir, H. V., & Ozensoy, E. (2019). CdTe quantum dot-functionalized P25 titania composite with enhanced photocatalytic NO2 storage selectivity under UV and vis irradiation. ACS Applied Materials & Interfaces, 11(1), 865-879. doi:10.1021/acsami.8b18036
Journal: ACS Applied Materials & Interfaces
Abstract: Composite systems of P25 (titania) functionalized with thioglycolic acid (TGA)-capped CdTe colloidal quantum dots (QDs) were synthesized, structurally characterized, and photocatalytically tested in the photocatalytic NOx oxidation and storage during NO(g) + O2(g) reaction. Pure P25 yielded moderate-to-high NO conversion (31% in UV-A and 40% in visible (vis)) but exhibited extremely poor selectivity toward NOx storage in solid state (25% in UV-A and 35% in vis). Therefore, P25 could efficiently photooxidize NO(g) + O2(g) into NO2; however, it failed to store photogenerated NO2 and released toxic NO2(g) to the atmosphere. CdTe QD-functionalized P25 revealed a major boost in photocatalytic performance with respect to pure P25, where NO conversion reached 42% under UV-A and 43% under vis illumination, while the respective selectivity climbed up to 92 and 97%, rendering the CdTe/P25 composite system an efficient broad-band photocatalyst, which can harvest both UV-A and vis light efficiently and display a strong NOx abatement effect. Control experiments suggested that photocatalytic active sites responsible for the NO(g) + O2(g) photooxidation and formation of NO2 reside mostly on titania, while the main functions of the TGA capping agent and the CdTe QDs are associated with the photocatalytic conversion of the generated NO2 to the adsorbed NOx species, significantly boosting the selectivity toward solid-state NOx storage. Reuse experiments showed that photocatalytic performance of the CdTe/P25 system can be preserved to a reasonable extent with only a moderate decrease in the photocatalytic performance. Although some decrease in the photocatalytic activity was observed after aging, CdTe/P25 could still outperform P25 benchmark photocatalyst. Increasing CdTe QDs loading from the currently optimized minuscule concentrations could be a useful strategy to increase further the catalytic lifetime/stability of the CdTe/P25 system with only a minor penalty in catalytic activity.
ISSN: 1944-8244
DOI: 10.1021/acsami.8b18036
Rights: This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Applied Materials & Interfaces, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see
Fulltext Permission: open
Fulltext Availability: With Fulltext
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