The Assembly of TiO 2 Nanoparticles into Micrometer‐Sized Structures, Photocatalytically Active Under UV and Vis Light

Micrometer‐sized structures consisting of TiO 2 nanoparticles were prepared using the sol–gel technique in combination with the structure‐directing agent triethanolamine ( TEA ). The interaction of the TEA with the hydrolyzed sol–gel products led to the formation of TEA titanate complexes, which then enabled the assembly of sol–gel‐precipitated nanosized powders. A subsequent thermal treatment of these powders resulted in the formation of micrometer‐sized structures consisting of TiO 2 anatase and rutile nanoparticles. To characterize the prepared powders, FTIR spectroscopy, XRD analysis, the Brunauer‐Emmett‐Teller method ( s BET ), UV –Vis spectrometry and electron microscopy ( FE ‐ SEM , and TEM ) were employed. The photocatalytic degradation of the azo dye known as methylene blue was monitored under UV and Vis irradiation and showed that the micrometer‐sized structures consisting of TiO 2 nanoparticles exhibited a similar photocatalytic activity to submicrometer‐sized structures consisting of TiO 2 nanoparticles prepared without TEA .