Strategies toward catalytic biopolymers: Incorporation of tungsten in alginate aerogels

Patrina Paraskevopoulou Pavel Gurikov Grigorios Raptopoulos Despoina Chriti Maria Papastergiou Zacharenia Kypritidou Vassilis Skounakis Ariadne Argyraki

We report the synthesis of W-doped biopolymer aerogels with potential applications to catalysis. The biopolymers were based on alginate, a cost-efficient natural material, and were prepared in environmentally friendly water/ethanol solutions. Gelation of alginate was induced by crosslinking with Ca2+. The resulting wet-gels were impregnated with an ethanolic solution of the ditungsten complex [W2(μ-OEt)2(OEt)2(EtOH)2Cl4] ({W =W}8+) and were dried with supercritical fluid (SCF) CO2 to yield W-doped alginate aerogels containing 10% w/w tungsten. Dry materials were characterized with FTIR, SEM/EDS, TGA, N2 porosimetry and He pycnometry. The bulk densities were low (<0.1 g cm-3), porosities were high (96% v/v), as well as the BET surface areas (380 m2/g). Pyrolysis of those aerogels at 800 oC under Ar yielded carbon along with a mixture of calcium tungstates, i.e., CaWO4 and Ca3WO6 (weight ratio: 70:30), while pyrolysis under O2 yielded the same tungstates, but with a different weight ratio (10:90). This can be a new process for Ca3WO6, which, due to its ordered double perovskite structure, is ideal for doping with metal ions, at relatively low temperature (800 oC versus >1000 oC in the literature). (EN)

scientific_publication_article

Επιστημονική δημοσίευση - Άρθρο Περιοδικού (EL)

Scientific publication - Journal Article (EN)

Θετικές Επιστήμες (EL)

Science (EN)

Εθνικό και Καποδιστριακό Πανεπιστήμιο Αθηνών

Πέργαμος

Άρθρο Περιοδικού (Journal Article)

Αγγλική γλώσσα

2018-01-01

uoadl:2818720

https://pergamos.lib.uoa.gr/uoa/dl/object/uoadl:2818720