@misc{10481/61388,
year = {2020},
month = {1},
url = {http://hdl.handle.net/10481/61388},
abstract = {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 (~35%) was higher than that of GO-H
(~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.},
organization = {This work was financially supported by project NORTE-01-
0145-FEDER-031049 (InSpeCt) funded by FEDER funds through
NORTE 2020 - Programa Operacional Regional do NORTE and by
national funds (PIDDAC) through FCT/MCTES (PTDC/EAMAMB/
31049/2017). We would also like to thank the scientific collaboration
under project ‘‘AIProcMat@N2020 - Advanced Industrial
Processes and Materials for a Sustainable Northern Region of Portugal
2020” (NORTE-01-0145-FEDER-000006, NORTE 2020, Portugal
2020 Partnership Agreement, through FEDER), project
‘‘Associate Laboratory LSRE-LCM” (UID/EQU/50020/2019 - FCT/
MCTES – PIDDAC) and project 2DMAT4FUEL (POCI-01-0145-
FEDER-029600 - COMPETE2020 – FCT/MCTES - PIDDAC). MP
acknowledges the PhD research grant from FCT (Ref. SFRH/
BD/102086/2014). LMPM acknowledges the Spanish Ministry of
Economy and Competitiveness (MINECO) and the European Social
Fund for a Ramon y Cajal research contract (RYC-2016-19347). GD
acknowledges the Slovenian Research Agency (P2-0393). PF acknowledges support from Prince Sultan Bin Abdulaziz International
Prize for Water–Alternative Water Resources Prize 2014},
publisher = {Elsevier Inc},
keywords = {Photocatalysis},
keywords = {Graphene oxide},
keywords = {Metal-free},
keywords = {Surface chemistry},
keywords = {Photoluminescence},
title = {Hummers’ and Brodie’s graphene oxides as photocatalysts for phenol degradation},
doi = {10.1016/j.jcis.2020.01.093},
author = {Pedrosa, Marta and Pastrana Martínez, Luisa María},
}