Hummers' and Brodie's graphene oxides as photocatalysts for phenol degradation

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:567

Article

Pedrosa, Marta¹  Da Silva, Eliana S.¹  Pastrana-Martinez, Luisa M.²  Drazic, Goran³  Falaras, Polycarpos⁴  Faria, Joaquim L.¹  Figueiredo, Jose L.¹  Silva, Adrian M. T.¹ 

[1] Univ Porto, Fac Engn, LSRE, LCM, Rua Dr Roberto Frias, P-4200465 Porto, Portugal

[2] Univ Granada, Fac Sci, Carbon Mat Res Grp, Dept Inorgan Chem, Campus Fuentenueva S-N, E-18071 Granada, Spain

[3] Natl Inst Chem, Dept Mat Chem, Hajdrihova 19, SI-1000 Ljubljana, Slovenia

[4] Natl Ctr Sci Res Demokritos, Inst Nanosci & Nanotechnol, Athens 15341, Greece

关键词: Photocatalysis;    Graphene oxide;    Metal-free;    Surface chemistry;    Photoluminescence;   

DOI  :  10.1016/j.jcis.2020.01.093

来源: Elsevier

【 摘 要 】

Undoped metal-free graphene oxide (GO) materials prepared by either a modified Hummers' (GO-H) or a Brodie's (GO-B) method were tested as photocatalysts in aqueous solution for the oxidative conversion of phenol. In the dark, the adsorptive capacity of GO-B towards phenol (similar to 35%) was higher than that of GO-H (similar to 15%). Upon near-UV/Vis irradiation, GO-H was able to remove 21% of phenol after 180 min, mostly through adsorption. On the other hand, by using less energetic visible irradiation, GO-B removed as much as 95% in just 90 min. By thorough characterization of the prepared materials (SEM, HRTEM, TGA, TPD, Raman, XRD, XPS and photoluminescence) the observed performances could be explained in terms of their different surface chemistries. The GO-B presents the lower concentration of oxygen functional groups (in particular carbonyl groups as revealed by XPS) and it has a considerably higher photocatalytic activity compared to GO-H. Photoluminescence (PL) of liquid dispersions and XRD analysis of powders showed lower PL intensity and smaller interlayer distance for GO-B relative to GO-H, respectively: this suggests lower electron-hole recombination and enhanced electron transfer in GO-B, in support of its boosted photocatalytic activity. Reusability tests showed no efficiency loss after a second usage cycle and over three runs under visible irradiation, which was in line with the similarity of the XPS spectra of the fresh and used GO-B materials. Moreover, scavenging studies revealed that holes and hydroxyl radicals were the main reactive species in play during the photocatalytic process. The obtained results, establish for the first time, that GO prepared by Brodie's method is an active and stable undoped metal-free photocatalyst for phenol degradation in aqueous solutions, opening new paths for the application of more sustainable and metal-free materials for water treatment solutions. (C) 2020 The Authors. Published by Elsevier Inc.

【 授权许可】

Free