Efficient methane decomposition to produce hydrogen and microwave absorption material by iron and nitrogen Co-doped Biocarbon: Synergistic mechanisms and performance

This study explores the fabrication of Fe–N co-doped biochar (Fe–NAC) from waste balsa wood as an efficient catalyst for methane decomposition and as a precursor to functional carbon materials. Ferric nitrate and urea were used as the respective sources of iron and nitrogen. The Fe-NAC catalyst achieved 85 % methane conversion within 200 min at 800 °C, a 3.4-fold improvement over the parent biochar (AC). The stable biochar structure anchors Fe₃N nanoparticles, forming a hierarchical porous catalyst that enhances performance. Theoretical calculations revealed that the Fe-N structure alters the electron distribution, facilitating efficient electron transfer from Fe sites to methane and intermediates, demonstrating a synergistic effect of heteroatoms and carbon supports. Additionally, Fe-NAC exhibited exceptional microwave absorption properties, achieving a minimum reflection loss (RL) of −42.48 dB at 14.96 GHz with a 4.67 GHz effective absorption bandwidth (EAB). Adjusting the thickness enabled coverage of the entire 4–18 GHz spectrum. Radar cross-section (RCS) simulations demonstrated superior microwave attenuation across a wide range of angles, surpassing other biochars. This study introduces a novel Fe-N biochar synthesis method, highlights its catalytic performance in hydrogen production, and demonstrates its potential in electromagnetic wave absorption, providing insights for green energy and functional material development.