Ceramic aerogels from TEMPO-oxidized cellulose nanofibre templates: Synthesis, characterization, and photocatalytic properties

• TiO2 and TiO2/SiO2 aerogels were prepared via sol–gel approach using TEMPO-oxidized cellulose nanofibres as template.
• The materials showed high adsorption capacity and degradative photocatalytic activity toward methylene blue and rhodamine B.
• The approach herein proposed is simple, green, and useful for the preparation of a larger class of ceramic cellular solids.

Aerogels are highly porous materials whose interesting chemico-physical properties can be exploited in several advanced applications. Ceramic aerogels based on titanium oxides, allow coupling the physical properties with the photocatalytic role of TiO2 in promoting pollutant photodegradation, selective organic photosynthesis, and antibacterial activity. Here, we prepared hybrid organic-ceramic aerogels via one-pot approach by mixing aqueous hydrogels of cellulose nanofibres with TiO2 or TiO2/SiO2 sols and subsequent freeze-drying of the obtained mixtures. The further calcination of the hybrid materials at suitable temperatures allowed achieving ceramic aerogels able to combine a pronounced adsorption efficiency of organic molecules with photocatalytic activity. The new materials have been characterized in terms of morphology, structure, and heterogeneous photo-degradation ability of potential pollutants. A possible explanation for the different behavior in adsorption affinity and photocatalytic efficiency is reported on the basis of the experimental evidences.

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