@phdthesis{Fettkenhauer2015, author = {Fettkenhauer, Christian}, title = {Ionothermale Synthese funktioneller Kohlenstoffnitrid basierter Materialien}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-78087}, school = {Universit{\"a}t Potsdam}, pages = {xii, 123}, year = {2015}, abstract = {Die Doktorarbeit behandelt die Synthese Kohlenstoffnitrid basierter Materialien in eutektischen Mischungen bivalenter Metallchloride. Der Fokus liegt dabei auf ZnCl2-, SnCl2- und CoCl2-haltigen eutektischen Mischungen, in denen die Kondensation gebr{\"a}uchlicher organischer Precursoren durchgef{\"u}hrt wird. Im Rahmen dessen wird untersucht wie durch die Reaktionsf{\"u}hrung in Salzschmelzen unterschiedlicher Lewis-Acidit{\"a}t, neben der Molek{\"u}lstruktur andere charakteristische Eigenschaften, wie Morphologie, Kristallinit{\"a}t und spezifische Oberfl{\"a}chen, der Materialien kontrolliert werden k{\"o}nnen. Dar{\"u}ber hinaus werden die optischen Eigenschaften der Materialien er{\"o}rtert und in diesem Zusammenhang die Eignung als Photokatalysatoren f{\"u}r den oxidativen Abbau organischer Farbstoffe und f{\"u}r die photokatalytische Wasserreduktion bzw. -oxidation untersucht. Zus{\"a}tzlich wird gezeigt, wie im System LiCl/KCl in einem einstufigen Prozess edelmetallfreie Kohlenstoffnitrid Komposite zur photokatalytischen Wasserreduktion hergestellt werden k{\"o}nnen.}, language = {de} } @article{ShalomGuttentagFettkenhaueretal.2014, author = {Shalom, Menny and Guttentag, Miguel and Fettkenhauer, Christian and Inal, Sahika and Neher, Dieter and Llobet, Antoni and Antonietti, Markus}, title = {In situ formation of heterojunctions in modified graphitic carbon nitride: synthesis and noble metal free photocatalysis}, series = {Chemistry of materials : a publication of the American Chemical Society}, volume = {26}, journal = {Chemistry of materials : a publication of the American Chemical Society}, number = {19}, publisher = {American Chemical Society}, address = {Washington}, issn = {0897-4756}, doi = {10.1021/cm503258z}, pages = {5812 -- 5818}, year = {2014}, abstract = {Herein, we report the facile synthesis of an efficient roll-like carbon nitride (C3N4) photocatalyst for hydrogen production using a supramolecular complex composed of cyanuric acid, melamine, and barbituric acid as the starting monomers. Optical and photocatalytic investigations show, along with the known red shift of absorption into the visible region, that the insertion of barbituric acid results in the in situ formation of in-plane heterojuctions, which enhance the charge separation process under illumination. Moreover, platinum as the standard cocatalyst in photocatalysis could be successfully replaced with first row transition metal salts and complexes under retention of 50\% of the catalytic activity. Their mode of deposition and interaction with the semiconductor was studied in detail. Utilization of the supramolecular approach opens new opportunities to manipulate the charge transfer process within carbon nitride with respect to the design of a more efficient carbon nitride photocatalyst with controlled morphology and optical properties.}, language = {en} } @article{ShalomInalFettkenhaueretal.2013, author = {Shalom, Menny and Inal, Sahika and Fettkenhauer, Christian and Neher, Dieter and Antonietti, Markus}, title = {Improving Carbon Nitride Photocatalysis by Supramolecular Preorganization of Monomers}, series = {Journal of the American Chemical Society}, volume = {135}, journal = {Journal of the American Chemical Society}, number = {19}, publisher = {American Chemical Society}, address = {Washington}, issn = {0002-7863}, doi = {10.1021/ja402521s}, pages = {7118 -- 7121}, year = {2013}, abstract = {Here we report a new and simple synthetic pathway to form ordered, hollow carbon nitride structures, using a cyanuric acid melamine (CM) complex in ethanol as a starting product. A detailed analysis of the optical and photocatalytic properties shows that optimum hollow carbon nitride structures are formed after 8 h of condensation. For this condensation time, we find a significantly reduced fluorescence intensity and lifetime, indicating the formation of new, nonradiative deactivation pathways, probably involving charge-transfer processes. Enhanced charge transfer is seen as well from a drastic increase of the photocatalytic activity in the degradation of rhodamine B dye, which is shown to proceed via photoinduced hole transfer. Moreover, we show that various CM morphologies can be obtained using different solvents, which leads to diverse ordered carbon nitride architectures. In all cases, the CM-C3N4 structures exhibited superior photocatalytic activity compared to the bulk material. The utilization of CM hydrogen-bonded complexes opens new opportunities for the significant improvement of carbon nitride synthesis, structure, and optical properties toward an efficient photoactive material for catalysis.}, language = {en} }