Raptopoulos, GrigoriosGrigoriosRaptopoulosPapastergiou, MariaMariaPapastergiouChriti, DespoinaDespoinaChritiEffraimopoulou, EleniEleniEffraimopoulouČendak, TomažTomažČendakSamartzis, NikolaosNikolaosSamartzisMali, GregorGregorMaliIoannides, TheophilosTheophilosIoannidesGurikov, PavelPavelGurikovSmirnova, IrinaIrinaSmirnovaParaskevopoulou, PatrinaPatrinaParaskevopoulou2021-05-202021-05-202021-03-24Materials Advances 2 (8): 2684-2699 (2021-04-21)http://hdl.handle.net/11420/9574Metal-doped polyurea-crosslinked alginate aerogel beads (X-M-alginate; M: Ca, Co, Ni, Cu) were prepared via the reaction of an aromatic triisocyanate (Desmodur RE) with the -OH groups on the surface of pre-formed M-alginate wet gels, and with adsorbed gelation water. The X-M-alginate aerogels consisted of 49-63% polyurea and contained 2-7% metal ions; they were fibrous macro/meso/microporous materials with porosities up to 94% v/v, and BET surface areas 245-486 m2 g-1, comparable to those of native M-alginate aerogels (258-542 m2 g-1). The pyrolysis of X-M-alginate aerogels (M: Co, Ni, Cu) at 800 °C yielded carbon aerogels (X-M-C; 33-37% yield) doped with the corresponding metal (as well as with Cu2O in the case of X-Cu-C), with crystallite sizes of around 22 nm. The X-M-C aerogels retained the general fibrous morphology of their precursor (X-M-alginate) aerogels, and while X-Co-C and X-Ni-C appeared similar, the fibrous morphology of X-Cu-C was distinctly different, indicating an effect of the metal on the nanostructure of the corresponding carbon. The porosities of all X-M-C aerogels were in the range of 88-92% v/v, including macro-, meso- and micropores. Their BET surface areas were in the range of 426-541 m2 g-1, of which 208-319 m2 g-1 was allocated to micropores. In addition to the metals, XPS, Raman and FTIR analyses showed the presence of oxygen and nitrogen functionalities. Carbon in the X-M-C aerogels showed signs of stacking of graphene oxide sheets (14-15 nm), but also a low degree of graphitization and a large number of defects. This work provides a direct, inexpensive method for the preparation of fibrous metal-, oxygen- and nitrogen-doped carbon aerogels with potential for catalytic and electrochemical applications.en2633-54092021826842699Royal Society of Chemistryhttps://creativecommons.org/licenses/by-nc/3.0/TechnikJournal Article10.15480/882.354910.1039/d0ma01025a10.15480/882.3549Journal Article