Dr. Wonoh Lee is an associate professor at School of Mechanical Engineering of Chonnam National University, South Korea. He received a Ph.D in Department of Materials Science & Engineering at Seoul National University. His research interest are mechanics-based interdisciplinary researches for inelastic materials including metals, organic/polymeric structural materials, fiber-reinforced composites, advanced fiber/textile, and nano-carbon materials. Ongoing works focus on catecholamine-based graphene hybrids and their three-dimensional carbon nanostructures for electrochemical energy storage electrodes. He has over 60 peer-reviewed journal publications.
To facilitate the immobilization of the silver nanoparticles with high crystallinity and stability, the mussel-inspired dopamine is functionalized on the surface of the graphene. Considering the unique adhesive property of a catechol group in the dopamine toward metallic ions, a large amount of silver nanoparticles can be coated on the surface of the dopamine-functionalized graphene. To use the high surface area of graphene, large-sized graphene sheets are prepared using the microwave heat treatment of graphite powder followed by chemical oxidation and exfoliation. In addition, the large-area graphene sheets are selectively collected by a pH-assisted fractionation technique and are confirmed by the green-light filtered optical microscopic images. The dopamine-mediated graphene hybrid with silver nanoparticles shows superior electrochemical activity with enhanced electrical conductivity by promoting the decoration of stable silver nanoparticles on the surface of graphene. The resulting hybrid exhibits 7.6 times and 1.6 times higher electrochemical capacitance than that of the bare and graphene/silver hybrid-modified glassy carbon electrodes, respectively.
Audience Take away:
• Various advantages of catecholamine chemistry such as high binding property toward metallic nanoparticles, easy functionalization with oxygen functional groups in graphene sheets, mechanically strong adhesive property, high carbon yield and nitrogen doping effect through high temperature annealing, and increase of hydrophilicity.
• Mussel-inspired dopamine functionalization on graphene surface.
• The catechol group in dopamine accelerated the surface immobilization of Ag NPs.
• The decorated Ag NPs had high stability and crystallinity.
• Dopamine-mediated graphene hybrid showed highly enhanced electrochemical activity.