Toward Scalable Processing of Porous Carbon Nanocomposites and Functional Nanomaterials

Abstract

Porous carbon materials, such as carbon aerogels, feature a combination of high surface area, electrical conductivity, and mechanical stability that has triggered interest in loading them with functional nanomaterials. Carbon aerogels are often derived from resorcinol–formaldehyde (RF) gels, which traditionally rely on base-catalyzed aqueous reactions that take long times at high temperatures (12+ hours, 80+°C), posing a bottleneck to scale-up. To address this issue, I present an alternative acid-catalyzed gelation process in acetonitrile, requiring just 2 hours at <45°C, en route to graphene– and transition metal dichalcogenide (TMD)–carbon aerogel composites. Both of these composites exhibit superior performance as supercapacitor electrodes versus plain carbon aerogels, and the graphene aerogel is also shown to enhance adsorption of an important lipophilic biomolecule, Coenzyme Q10, for possible drug loading applications. Additionally, to explore the possibility of tailoring the microstructure of such aerogel composites, I present optoelectronic tweezers (OET) as a viable means to align, manipulate, and pattern particles of graphene oxide—the precursor to graphene in our aerogel composites—in water using low-intensity light. With an eye toward OET patterning for another important nanomaterial, I also report a simple hydrothermal synthesis to obtain large yields of palladium nanowires (PdNWs), whose ultra-high aspect ratio greatly facilitates OET manipulation relative to more uniform geometries. Finally, going back to porous carbon composites, I take on a different approach to accelerating synthesis by investigating a solvent-free preparation of the polymer precursor based on bisphenol A and hexamethylenetetramine, which eliminates the need for time-consuming solvent exchange and supercritical drying. Beyond synthetic insights, I demonstrate that carbons produced by this approach can serve as scaffolds to stabilize nanoscale silicon for high-capacity lithium-ion battery anodes.