Reoxidation of graphene oxide: Impact on the structure, chemical composition, morphology and dye adsorption properties

Author(s)

Zito, Cecilia A. ^[1] ; Perfecto, Tarcisio M. ^[1] ; Mazon, Talita ^[2] ; Dippel, Ann-Christin ^[3] ; Koziej, Dorota ^[4] ; Volanti, Diogo P. ^[1]

Affiliation

^[1] Sao Paulo State Univ UNESP, Lab Mat Sustainabil LabMatSus, Rua Cristovao Colombo 2265, BR-15054000 Sao Jose Do Rio Preto - Brazil

^[2] Ctr Informat Technol Renato Archer CTI, Rod D Pedro 1, KM 143-6, BR-13069901 Campinas, SP - Brazil

^[3] Deutsch Elektronen Synchrotron DESY, Notkestr 85, D-22607 Hamburg - Germany

^[4] Univ Hamburg, Ctr Hybrid Nanostruct CHyN, Inst Nanostruct & Solid State Phys, Luruper Chaussee 149, D-22607 Hamburg - Germany

• Document type: Journal article
• Source: Applied Surface Science; v. 567, NOV 30 2021.
• Web of Science Citations: 0

Abstract

The chemical composition, oxidation degree, and sheet size strongly affect the properties of graphene oxide (GO). Therefore, much effort has been directed to improve the synthesis of GO and control its structure. Herein, we report the reoxidation of GO using milder conditions of a modified Hummers' method, including shorter reaction times and a reduced proportion of chemicals to obtain the reoxidized GO (Ox-GO). The reoxidation impact was evaluated by studying the materials' adsorption performance towards methylene blue (MB) and rhodamine B (RB). Compared to GO, Ox-GO presents a similar C/O ratio, increased interlayer spacing, smaller sheets with holes, a higher exfoliation degree, and slight differences in each oxygenated functional group. Our measurements evidence that Ox-GO has an MB adsorption capacity more than 30% higher than GO under different conditions of dye concentration and pH. Moreover, Ox-GO also shows a notable improvement in the RB removal for a high dye concentration, where the removal capacity is almost 40% higher than that of GO. The enhancements in the dyes' removal are attributed to the increased accessible surface area of Ox-GO, which provides more sites for dyes' adsorption. (AU)

• FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
• Grantee: Elson Longo da Silva
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 18/08271-7 - Structural, electronic, and chemical characterization of graphene acid composites with yolk-shell CeO2 and yolk-shell Pd-CeO2 nanospheres
• Grantee: Cecilia de Almeida Zito
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• FAPESP's process: 20/06421-1 - Development of sensors derived from metal-organic frameworks to detect microbial volatile organic compounds
• Grantee: Diogo Paschoalini Volanti
• Support Opportunities: Regular Research Grants
• FAPESP's process: 16/25267-8 - Graphene acid composites with hollow CeO2 and Pd-CeO2 yolk-shell structures applied as volatile organic compounds sensors
• Grantee: Cecilia de Almeida Zito
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 18/00033-0 - Sensing devices of volatile organic compounds based on ZnO hollow/p-type semiconductors heterostructures
• Grantee: Tarcísio Micheli Perfecto
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 17/01267-1 - Graphene acid-hollow metal oxides composites for gas sensor
• Grantee: Diogo Paschoalini Volanti
• Support Opportunities: Regular Research Grants