ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Morphology, structure, and photoactivity of two types of graphene oxide–TiO2 composites

Anca Peter, Leonard Mihaly-Cozmuta, Anca Mihaly-Cozmuta, Camelia Nicula, Agnieszka Jastrzębska, Patrycja Kurtycz, and Andrzej Olszyna

Department of Chemistry, Technical University Cluj Napoca, Victor Babes 76, 430083, Baia Mare, Romania

E-mail: peteranca@yahoo.com

Abstract: Two types of graphene oxide-TiO₂ composites were prepared: one by including graphene oxide flakes in the TiO₂ sol, followed by thermal treatment (GI composite) at 300°C, and the second by including graphene oxide flakes in the calcined (at 500°C) TiO₂ xerogel (GII composite). The composites were characterized by SEM, TEM-EDS, TEM-SADP, STEM-HAADF, HRTEM coupled with FT, XRD, and XPS. Photocatalysis results were fitted to different kinetic models (pseudo-first and pseudo-second kinetics, intraparticle Weber-Morris diffusion, film diffusion, and external mass transfer). The results showed that by introducing graphene oxide flakes in the TiO₂ sol, followed by thermal treatment at 300°C (GI composite), an efficient graphene oxide-TiO₂ catalyst with high specific surface area, heterogeneity, and many graphitized areas can be obtained. Complete crystallization of the composite is not the key issue for the best photoactivity achievement. The rate limiting step in the photocatalytic process is the photooxidation of SA molecules on the TiO₂ surface.

Keywords: graphene oxide-TiO2 – photocatalytic activity – kinetic model – morpho-structural characterization

Full paper is available at www.springerlink.com.

DOI: 10.1515/chempap-2015-0088

Chemical Papers 69 (6) 839–855 (2015)