KOH-assisted Fe/Ni biochar nanocomposite derived from sugarcane bagasse for rapid hydrogen generation

Catalyst development is crucial for improving the sustainability and economic viability of clean energy technologies and reducing fossil fuel dependency. In this work, the Fe/Ni-loaded KOH-activated sugarcane bagasse biochar (Fe/Ni–KOH@SCBB) was prepared. The biochar was chemically activated at a biochar-to-KOH ratio of 1:4, followed by heat treatment at 900 °C, yielding a highly porous carbon framework with excellent metal dispersion capacity. Comprehensive characterization using UV-visible spectroscopy, FTIR, Raman, XRD, BET surface area analysis, SEM, EDX, ICP-OES, XPS, and TGA confirmed the successful formation of the Fe/Ni-loaded porous carbon catalyst. Both the activated biochar and the biochar loaded with Fe/Ni had high surface areas of 685.4 and 432.7 m 2 g −1 , respectively. The gradual reduction upon Fe/Ni incorporation suggests partial pore blocking by the supported metal species, while significant hierarchical micro–mesoporosity is retained. The catalytic activity of Fe/Ni–KOH@SCBB was evaluated for formic acid dehydrogenation. The best result was obtained for the nominal 1:1 Fe/Ni catalyst, with ICP-OES confirming an experimental Fe/Ni ratio of 1.01:1, using 10 mg of catalyst, formic acid/sodium formate (FA/SF) ratio of 1:1, pH 8, and 60 °C, yielding a total metal normalized apparent TOF (TOF app ) of 2341.6 h −1 . Enhanced catalytic performance is associated with the beneficial bimetallic Fe/Ni interaction, supported by the XPS-derived changes in the local electronic environments of Fe and Ni, coupled with the accessible porous structure of the KOH-activated biochar. The catalyst also exhibited good durability, retaining about 90% of its initial activity after five consecutive catalytic cycles.