Graphene oxide-P25 photocatalysts for degradation of diphenhydramine pharmaceutical and methyl orange dye

• Tipo: Artigo em Revista Científica Internacional
• Data: 2013

Autores

Sergio Morales Torres (Autor) FEUP; Luisa M Pastrana Martinez (Autor) Outra; Jose L Figueiredo (Autor) FEUP; Joaquim L Faria (Autor) FEUP; Adrian M T Silva (Autor) FEUP

Revista

Título: Applied Surface Science

Vol. 275

Páginas: 361-368

ISSN: 0169-4332

Editora: Elsevier

Indexação

ISI Web of Knowledge - 91 Citações

ISI Web of Science

Scopus - 117 Citações

Classificação Científica

FOS: Ciências da engenharia e tecnologias > Engenharia dos materiais

Outras Informações

ID Authenticus: P-005-00Q

DOI: 10.1016/j.apsusc.2012.11.157

Abstract (EN): Graphene oxide (GO) and the benchmark TiO2 photocatalyst (P25) were used to prepare different composites (GOP), by a simple method of mixing and sonication, varying the GO content and the heat-treatment temperature under nitrogen. The composites were characterized by thermogravimetric (TG) and differential thermogravimetric (DTG) analyses, scanning electron microscopy (SEM), physical adsorption of nitrogen, UV-Vis and IR diffuse reflectance spectroscopies (DRUV and DRIFT), and point of zero charge (pH(PZC)) measurements. The morphology, microporosity and S-BET of the composites did not vary significantly in comparison to P25, while an increase of their mesoporosity and mesopore diameter were observed due to the formation of GO aggregates coated with P25 nanoparticles. The aggregates were stabilized by the formation of Ti-O-C bonds, which in turn produced a narrowing of the band gap relative to P25. The surface chemistry of GOP composites varied with the GO content, being more acidic when higher GO content was used. The photocatalytic performance was evaluated for the degradation of diphenhydramine (DP) pharmaceutical and methyl orange (MO) dye under near-UV/Vis irradiation. The first order rate constant of MO photodegradation increased four times for some GOP composites with relation to P25 (i.e., from k = 52 x 10(-3) to 207 x 10(-3) min(-1)). Comparable efficiencies were observed when DP was used as model pollutant (i.e., around k = 54 x 10(-3) min(-1)). The best performing photocatalyst was that containing 1.4 wt.% GO and treated at 200-300 degrees C. The improved performance was attributed to the reduction of GO during the thermal treatment and to the good contact between the TiO2 and the carbon phases.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 8