Synthesis of activated carbon from sugarcane bagasse using blends of hydroxides for maximizing reaction targeted at obtaining hydrogen peroxide

Abstract

This study investigates the potential reutilization of sugarcane bagasse (SCB) – a highly abundant residue generated from the sugar and ethanol industries. Activated carbon (AC) with optimized selectivity toward hydrogen peroxide (H2O2) electrogeneration was obtained by applying a customized process that involved the impregnation of the residue with KOH and NaOH and thermal activation. To optimize the properties of the AC, the following synthesis parameters were evaluated: proportion of KOH/NaOH used in the impregnation process, activation temperature, holding time (of the activation temperature), and concentration of activating solution. The optimized condition obtained was NaOH at 10 %m/v, activation temperature of 650 ºC, and holding time of 60 min; this condition was found to be more sustainable than that of the traditional processes employed in obtaining black carbon. The near-optimal condition generated an AC with outstanding wettability, high amount of oxygenated groups on the surface, and a surface area of 121.2 m2 g-1, with good theoretical selectivity toward H2O2 electrogeneration (90 % at -0.4 vs. RHE) and an onset potential of +0.3 vs RHE. Our findings show that the SCB-derived AC material could be used as an environmentally friendly and economical alternative to conventional petroleum-derived carbon materials commonly used in H2O2 electrogeneration and as a support material for other active materials. The study shows that the precise equilibrium of the physical attributes of the carbon material and the chemical composition of its surface, influenced by the activation process, are key factors that affect catalytic efficiency in the in situ electrogeneration of H2O2.