Super expanded freestanding 3D graphene foam as a versatile platform for CO2 capture and hydrogenation

Abstract

A robust fabrication process has been developed to produce super-expanded freestanding 3D reduced graphene oxide foams (SE-rGO) with an outstanding porous architecture and stable geometry for effective capture (from the atmosphere) and the conversion of CO2 into fuel. The 3D SE-rGO foam was prepared using salicylic acid-induced exfoliation of graphene layers based on a template-assisted process. The foam was then coated with a thin layer of polydopamine (pDA) to enhance its physical and functional properties. The morphology and structural integrity of the foam were examined using SEM, XRD, XPS, and TGA. Owing to its unique 3D porous architecture and large specific surface area (767 m2/g, SSA), the foam displayed excellent multifunctional attributes, namely high CO2 adsorption capacity (4.17 mmol/g) and catalytic support for effective CO2 hydrogenation to formate. The key catalytic activity was made possible by coating the foam with palladium nanoparticles. The coated foam showed outstanding hydrogenation of CO2 to formate with a maximum yield of 24.3% at 120 °C. Given its potential, this graphene foam can be a promising and versatile material for both CO2 capture and CO2 hydrogenation.