Influence of KOH, NaOH and temperature on annoni grass ash-derived few layer and sponge-like graphene studied by Raman spectroscopy

da Rosa R.Q.B.; de Figueiredo J.A.P.; Zapata M.J.M.; Azzi P.C.; Trindade E.C.; Reyna Zegarra L.B.; de Menezes J.W.; Valsecchi C.; Girardi A.; Armas L.E.G. · Diamond and Related Materials (2026) · DOI: 10.1016/j.diamond.2026.113680

Resumen

In this work, we report the influence of the chemical reagents potassium hydroxide (KOH), sodium hydroxide (NaOH) and temperature on the structural quality of graphene derived from annoni grass ash, by Raman spectroscopy. For this purpose, the annoni grass (AG) leaves were combusted at 400 °C for 60 min to obtain the annoni grass ash (AGA). For graphene production, the AGA was activated with KOH and NaOH at 800, 850 and 950 °C for 60 min. SEM images and Raman analysis revealed that when AGA is activated with KOH, few layer graphene (FLG) is produced, whereas activation with NaOH results in sponge-like graphene with lower structural disorder. On the other hand, 850 and 950 °C are the optimal temperatures for producing both FLG and sponge-like graphene using KOH and NaOH as activating agents. Disorder analysis, using the ratio between the integrated intensities of the D = DS + DA, G = GS + GA, DA, and GA bands (ID/IG, IDA/IGA), showed that sponge-like graphene exhibits lower disorder than FLG. Additionally, the I2D/IG ratios indicate that for sponge-like graphene, the number of layers decreases as the temperature increases. These results indicate that graphene production from AG biomass, an invasive weed of the agricultural fields, represents a promising route for converting an abundant and low-value residue into value-added carbon materials through a simple and cost-effective process.

Instituciones: Universidad Nacional del Santa