Abstract: Photocatalysis plays a pivotal role in today’s global issues, meeting the requirements of sustainable chemistry and green organic synthesis, with applications in a large variety of processes, from organic pollutants mineralization to fine organic reactions. CeO₂ NPs is a feasible "platform" for the next generation of photocatalysts, since CeO₂ has a band gap similar to TiO₂ NPs (Eg = 3.19 eV), a particular outer electron configuration ( [Xe] 4f¹5d¹6s²) that enhance the electron transfer, low price (6.36 USD/kg in 2018), reversible shift of the oxidation state between Ce³⁺ and Ce⁴⁺, in the cubic fluorite structure form oxygen vacancies, are long-term stable and nontoxic. Unfortunately, the use of inorganic nanoparticles as photocatalysts is limited by their agglomeration tendency, which leads to a decrease in their surface area and eventually of their photocatalytic efficiency, but also to the difficulties encountered during their separation and reuse. To overcome these drawbacks, in the literature was emphasized that the use of various polymers as supports for the efficient immobilization of active photocatalytic nanoparticles could represent a viable solution, due to some unquestionable advantages of polymeric supports: resistance to ultraviolet radiations, high durability, chemical stability, and easy availability.

In view of all these information, this study reports the design of multiple cellulose-derived platforms for efficient immobilization of pristine/functionalized CeO₂ nanoparticles. The resulted nanocomposites were successfully tested as photocatalysts for the photodegradation under UV irradiation of the hazardous pollutants methyl orange, Congo red and 4–nitrophenol or for the photoreduction reaction of 4–nitrophenol. The reusability of the photocatalysts after several cycles and their efficiencies under visible irradiation were also tested.

Keywords: CeO₂ NPs, surface nanoparticles functionalization, cellulosic matrix, cellulose regeneration/oxidation, photocatalysis/photoreduction

Acknowledgements: This work was supported by a grant of the Romanian Ministry of Education and Research, CNCS–UEFISCDI, project number PN-III-P1-1.1-TE-2019-1245 (23/27.08.2020), within PNCDI III.

Biography: Dr. Andreea L. Chibac-Scutaru is a Researcher at the "Petru Poni" Institute of Macromolecular Chemistry of Romanian Academy, Romania. Her main research expertise is as below:
- development of materials for technical applications (photocatalysis, UV shielding, fuel cells) starting from renewable sources (cellulose);
- development of acrylate-based nanocomposite/polymeric materials for fluorescent sensors and photocatalysis (degradation of organic pollutants and organic reactions) applications;
- synthesis of monomers, (block)copolymers, inorganic nanoparticles in situ and ex situ (Ag, Au, TiO₂) and organic-inorganic hybrid composites;
- photopolymerization studies;
- structural and physicochemical characterization of the synthesized compounds/materials: FTIR, NMR, UV-Vis, fluorescence, SEM, EDX, TEM, XRD, SAXS etc;
- photocatalysis- catalytic activity study, reaction mechanism study;
- fluorescence studies – quenching mechanism, selective detection.