@article{EitelPanzerHagemannetal.2025, author = {Eitel, Dominik and Panzer, Sabrina and Hagemann, Ulrich and Heidelmann, Markus and Joseph, Fabio and Helbig, Jens and Helbig, Uta and Kaliwoda, Melanie and Teipel, Ulrich}, title = {Structural Characterization of Carbon-Doped and Carbon-Coated Core-Shell TiO2 Nanoparticles}, series = {Advanced Materials Interfaces}, volume = {13}, journal = {Advanced Materials Interfaces}, number = {2}, publisher = {Wiley}, issn = {2196-7350}, doi = {10.1002/admi.202500770}, pages = {12}, year = {2025}, abstract = {Carbon-doped TiO2 nanoparticles were prepared by a facile carbothermal treatment at different temperatures. The synthesis was conducted in a rotary tube furnace under an acetylene/nitrogen gas flow. A detailed analysis of the morphology of the particles revealed a layered graphene structure surrounding the TiO2core with a temperature-shell thickness of 1-1.5 nm. The material exhibits a significant shift in the Raman Eg(1) mode toward higher wavenumbers. High carbon contents were determined by X-ray photoelectron spectroscopy. This led to the conclusion that in addition to the carbon in the shell, carbon is also incorporated into the TiO2 structure. Substitutional doping in favor of titanium or oxygen atoms could be excluded based on XPS measurements due to the absence of Ti-C bonds and the lack of changes in lattice parameters of the unit cell or microstrain. An interstitial incorporation of carbon is therefore most likely. Either the incorporation of carbon or the carbon shell suppressed the phase transition from anatase to the thermodynamically stable rutile which is expected above 600 Celsius. Additionally, the process inhibits the crystallite growth at higher treatment temperatures.}, language = {en} } @article{EitelGramlHoppeetal.2023, author = {Eitel, Dominik and Graml, Johanna and Hoppe, Julia and Kaliwoda, Melanie and Hornfeck, Markus and Helbig, Uta}, title = {Synthesis and Structure of Carbon-doped TiO2 by Carbothermal Treatment}, series = {Nano Select}, volume = {4}, journal = {Nano Select}, number = {7}, publisher = {Wiley}, issn = {2688-4011}, doi = {10.1002/nano.202300022}, pages = {454 -- 461}, year = {2023}, abstract = {Carbon modified titanium dioxide (TiO2) is a promising candidate for catalytic applications or fuel cells, where the modified oxide could replace currently used catalyst support materials. Carbothermally treated TiO2 was successfully prepared by annealing under acetylene/nitrogen gas flow in a rotary tube furnace. The carbon content in the TiO2 samples ranged from 5 to 14.5 wt.-\% as determined by thermogravimetric measurements. The powders showed suppression of the phase transition from anatase to rutile up to a treatment temperature of 825°C. Above 600°C rutile is the thermodynamically stable phase, therefore the suppression must be attributed to either carbon in the lattice or the reducing atmosphere in the furnace. Raman spectra revealed the characteristic G and D bands, indicating the formation of carbonaceous species in the samples. In addition, a shift of the anatase Eg(1) band was observed indicating a lattice disorder pointing toward carbon incorporation into the lattice. Diffuse reflectance spectra show sub band gap absorption together with a shift of the absorption edge. Depending on the extraction method of band gaps from spectra, the band gap values show a decrease or increase with increasing carbon content. Details of the evaluation and interpretation of the spectra are discussed.}, language = {en} }