High Surface Area Microporous Activated Carbon from Corn Fiber Using Graphene Oxide-Assisted Hydrothermal Carbonization

Abstract

This study investigated a novel process that explored the use of graphene oxide (GO) as a catalyst in the hydrothermal carbonization (HTC) process of low-value, high moisture-containing corn fiber (CF) to analyze the morphology, surface area, and porosity characteristics of activated carbon (AC) derived from GO-assisted hydrochar. The SEM results showed significant alteration to the hydrochar morphology revealing carbon spheres with flakes or platelet-like structures when GO was added to the process, which led to increased carbonization and promoted the hydrochar surface area. The surface areas of the ACs produced from the hydrochars were further increased, and a well-developed porous structure was produced with significant micropore volume. The highest surface area of 2549.1 m2/g obtained for the AC derived from the hydrochar with the highest GO ratio. Despite the absence of a strong trend between the GO ratio and AC surface area, the SEM analysis and pore size results revealed that the ACs derived from the GO-assisted hydrochars had more intact structures and smaller micropores with interconnected pore channels which would be very favorable for hydrogen storage capacity. The nitrogen content in the ACs was also found to be comparable or higher than carbons from other studies using nitrogen doping steps and was detected in surface functional groups through FT-IR and XPS analysis. Overall, the developed process provides valuable insight into the influence of GO for tailoring porous carbon materials to enhance surface area and pore structure in low-cost and effective bio-based adsorbents, offering opportunities for emerging applications while promoting circular economy principles.