Effect of adsorbate geometry and hydrogen bonding on the enhanced adsorption of VOCs by an interfacial Fe3O4–rGO heterostructure

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 473; p. 145346
• Main Authors: Lee, Seongbin, Kim, Sooyeon, Soo Han, Sang, Kim, Dong-Wan, Lee, Jiwon, Oh, Youngtak
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2023
• Subjects: Density functional theory; Fe3O4; Geometric gas adsorption; Interfacial heterostructure; Reduced graphene oxide; Volatile organic compounds; Volatile organic compounds; Fe3O4; Density functional theory; Reduced graphene oxide; Geometric gas adsorption; Interfacial heterostructure
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2023.145346

•pH-induced liquid-phase reduction yielded controllable carbon adsorbent surface.•Epoxy O functions as Fe3O4 anchoring site for selective VOCs adsorption.•Fe-rGOs possess high adsorption potential for C6 amphiphilicVOCs.•Charge density difference, H-bonding, and adsorbate geometry governs VOC adsorption. Volatile organic compounds (VOCs) produced from a wide range of industrial and household chemicals are toxic to human health. Hence, effective VOC removal strategies such as adsorption are essential. Developing a carbon-based adsorbent for the selective adsorption of VOCs without affecting its inherent adsorption capacity is challenging. In this study, we prepared three Fe3O4-doped reduced graphene oxide (Fe-rGO) materials via a liquid-phase reduction technique under acidic, neutral, and basic coagulation conditions. The Fe-rGO adsorbents exhibited a hydrolysis-induced GO network with a wrinkled layer morphology. Acidic conditions yielded an rGO surface with a large number of O-functional groups (epoxy and carboxylic groups), which act as anchoring sites for the growth of Fe3O4 nanoparticles. The synergistic effect of Fe3O4 domains and O active sites led to the effective and selective adsorption of amphiphilic VOCs including C4-C7 alkanes, ketones, and aromatic compounds (10.8–63.2 mg g−1). Experimental analyses and density functional theory calculations revealed three crucial factors that determine the improved amphiphilic VOC adsorption of the Fe-rGO materials: geometry of the adsorbate, hydrogen bonding at the rGO surface, and Fe3O4 nanoparticles controlling the charge density. Our facile and effective rGO surface manipulation strategy involving the fabrication of a metal oxide–carbon heterostructure provides a selective adsorption platform for amphiphilic VOCs.