The transformation of agro-waste into biochar using thermochemical processes aids in the management and disposal of biomass with the potential to provide significant energy. Different biochars exhibit different characteristics and performances depending on the fabrication method employed. Besides, many applications, such as remediation to adsorb heavy metals which favor biochars rich with oxygen-containing functional groups on their surface. Therefore, this study deals with the catalytic carbonization of the rachis part in windmill palm trees with ferrocene at different temperatures (300, 350, 450, and 500 degrees C), time intervals (25, 40, and 90 min.), and ratios (3:1, 3:2, and 3:3 palm tree: ferrocene ratio) to produce oxidized nanobiochar. The highest electronegativity’s (-61.8 and -64 mV) for PTONB were observed when samples were prepared at 350 degrees C, 90 min., 3:1 PT:F and 350 degrees C, 25 min., 3:2 PT: F, respectively. Morphological analysis showed that, the carbonization of windmill palm tree at 350 degrees C, 90 min. without ferrocene give spherical nano-biochar with bulky particle size of 237 nm. However, after ferrocene treatment, the nanobiochar particle size was reduced, ranging from 87 to 3 nm. Thus, the ferrocene/palm tree catalytic carbonization process is highly relevant to decreasing particle sizes. Consequently, based on the findings from physicochemical analyses (e.g., SEM-EDX, ATR-FTIR, X-ray diffraction, and high-resolution TEM), a straightforward and rapid method to synthesize an oxidized nano-biochar, with a wide variety of structural characterizations, at a low temperature in a single step under a muffled atmosphere has been developed. [GRAPHICS] .