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Author Raes, A.; Ninakanti, R.; Van den Bergh, L.; Borah, R.; Van Doorslaer, S.; Verbruggen, S.W. url  doi
openurl 
  Title Black titania by sonochemistry : a critical evaluation of existing methods Type A1 Journal article
  Year (down) 2023 Publication Ultrasonics sonochemistry Abbreviated Journal  
  Volume 100 Issue Pages 106601-106609  
  Keywords A1 Journal article; Theory and Spectroscopy of Molecules and Materials (TSM²); Laboratory of adsorption and catalysis (LADCA)  
  Abstract In the field of photocatalysis, the fabrication of black titania is a booming topic, as it offers a system with improved solar light harvesting properties and increased overall efficiency. The darkening of white TiO2 powders can be ascribed to surface hydroxylation, oxygen vacancies, Ti3+ centres, or a combination thereof. A handful of studies suggests these defects can be conveniently introduced by acoustic cavitation, generated during sonochemical treatment of pristine TiO2 powders. In reproducing these studies, P25 TiO2 samples were ultrasonicated for various hours with a power density of 8000 W/L, resulting in powders that indeed became gradually darker with increasing sonication time. However, HAADF–STEM revealed that extensive erosion of the sonotrode tip took place and contaminated the samples, which appeared to be the primary reason for the observed colour change. This was confirmed by UV–Vis DRS and DRIFTS, that showed no significant alteration of the catalyst surface after sonication. EPR measurements showed that only an insignificant fraction of Ti3+ centres were produced, far less than in a TiO2 sample that was chemically reduced with NaBH4. No evidence of the presence oxygen vacancies could be found. The enhanced photocatalytic activities of ultrasonicated materials reported in literature can therefore not be ascribed to the synthesis of actual black (defected) TiO2, but rather to specific changes in morphology as a result of acoustic cavitation. Also, this study underlines the importance of considering probe erosion in sonochemical catalyst synthesis, which is an unavoidable side effect that can have an important impact on the catalyst appearance, properties and performance.  
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  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 001084391500001 Publication Date 2023-09-15  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1350-4177 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 8.4 Times cited Open Access OpenAccess  
  Notes Approved Most recent IF: 8.4; 2023 IF: 4.218  
  Call Number UA @ admin @ c:irua:198848 Serial 8838  
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