Physico-chemical properties of pristine graphene and its performance as electrode material for electro-Fenton treatment of wastewater. (1st October 2016)

• Record Type: Journal Article
• Authors: Mousset, Emmanuel; Wang, Zuxin; Hammaker, Joshua; Lefebvre, Olivier
• Is Part Of: Electrochimica acta. Volume 214(2016)
• Page Start: 217
• Page End: 230
• Publication Date: 2016-10-01
• Subjects: 3D porous cathode -- electrocatalytic activity -- electro-Fenton -- graphene -- nanomaterials; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2016.08.002
• Languages: English
• ISSNs: 0013-4686

Abstract

Graphical abstract: Highlights: Graphene monolayer, multilayer and foam were tested as cathodes in electro-Fenton. Performance increases as the thickness and the porosity of the graphene increase. Graphene foam is more energy-efficient than conventional carbon felt. Electro-Fenton is more energy-efficient than conventional AOPs. Abstract: This paper reports for the first time the performance of pristine graphene – in the form of graphene monolayer (Gmono ), graphene multilayer (Gmulti ) and graphene foam (Gfoam ) – as cathode material in an electrochemical advanced oxidation process known as electro-Fenton (EF) for wastewater treatment. This study led to three major findings: (i) the electrogeneration of H2 O2 was proven feasible with the three graphene materials at an optimal cathodic potential ( E cat ) (−0.6 V vs Ag/AgCl) comparable to that obtained with other carbon-based cathodes such as graphite and carbon felt (Cfelt ); (ii) for all forms of graphene, the Fe 2+ regeneration rate and the H2 O2 production yield were sufficient to sustain the formation of OH through the Fenton reaction, leading to the degradation and mineralization of phenol, used as a model pollutant and; (iii) over the 3 graphene materials, Gfoam exhibited the highest H2 O2 electrogeneration yield (4.25 mg-H2 O2 L −1 cm −3 ), degradation rate (0.0081 min −1 ) and yield (78% after 3 h), mineralization rate (0.0818 h −1 ) and yield (50% after 8 h). The superiority of Gfoam was attributed to its high purity (I(2D)/I(G) = 1.58, C1s/O1S = 22), low interfacial charge-transfer resistance ( R ct ) (1.6 Ω), high electroactive surface area (55.017 cm 2 ) and three-dimensional (3D) porous structure (100–600 μm pore diameter), allowing it to outcompete conventional 3D carbon-based cathode materials in terms of efficiency and energy requirements. These results open up the possibility to use pristine graphene in EF for the treatment of wastewater.