Dr. Christos Trapalis Christos Trapalis Ph.D., is director of Research and Head of “Nanofunctional and Nanocomposite Materials Laboratory”, NCSR Demokritos. His scientific interests are focused on nanoscience and nanotechnology, visible light active photocatalysts for NOx removal and water splitting, carbon based materials, functionalized graphene and graphene oxide, 2D heterostructures, nanostructured powders and coatings and hybrid organic–inorganic materials.
Christos has taught “Physical Chemistry”, “Technology of Glass and Ceramics” at HTEI Athens (1994-2004), and “Physical Chemistry” at the Hellenic Open University (2009-14). He has been elected Prof. of “Advanced Materials” at the Department of Products Design Engineering, Aegean University (2004-8), but finally decided to stay at NCSR Demokritos. During the last 10 years he participated in more than 15 research programs, coordinated 12 of them and raised for NCSR Demokritos more than 1,5,0 M€. He is reviewer of more than 40 scientific journals with more than 110 publications in peer reviewed journals, 2500 citations, 5 patents, and H- index 28.
TiO2 anatase nanoplates were fabricated by a solvothermal method using titanium isopropoxide as a titanium precursor and HF as a capping agent in order to enhance the formation of the {0 0 1} crystal facets of the anatase crystal. Different surface modification procedures were applied in order to remove the adsorbed fluoride anions on the {0 0 1} crystal facets of the nanoplates. The first procedure was by calcining the as-prepared TiO2 anatase nanoplates up to 600 °C and the second one was by washing them with a NaOH aqueous solution. The surface modification procedure leads to the formation of two different morphologies of the TiO2 anatase nanoplates which exhibited tunable photocatalytic selectivity in air pollutants purification. The calcined nanoplates became larger and their {1 0 1} crystal facets expanded by shrinking the {0 0 1} crystal facets. In contrast the washed nanoplates maintained their shape which was formed by the solvothermal method. All samples, exhibited high photonic efficiency for air pollutants oxidation. The calcined TiO2 anatase nanoplates exhibited the best photocatalytic activity in oxidizing the NO gas to NO2 and NO3− whereas the washed TiO2 anatase nanoplates, preserving the initial morphology, exhibited the best photocatalytic activity in decomposing acetaldehyde. It was demonstrated that the dominant exposed {1 0 1} or {0 0 1} crystal facets of the TiO2 anatase nanoplates is the key factor in tuning the adsorption selectivity of the air pollutants.