Steam reforming of biomass tar using the low-cost incineration bottom ash as catalyst

Toluene steam reforming (TSR) is an effective route for converting biomass tar model compounds into H₂-rich syngas, but the practical application of Ni-based catalysts is limited by Ni sintering and coke deposition under high-temperature reforming conditions. In this work, municipal solid waste (MSW) incineration bottom ash (IBA) was converted into a waste-derived catalyst support through a CaO extraction-residue passivation route, and Ni-based catalysts were subsequently prepared for TSR. Considering the trace amount of Fe originally present in the IBA-derived support and the known promotional effect of Fe on Ni-based reforming catalysts, additional Fe was introduced to regulate the Ni-Fe interactions and optimize the catalytic structure. A series of xFe-15Ni/MS₁₅Ca₈₅ catalysts were synthesized and evaluated for toluene steam reforming at 850 °C with a S/C ratio of 3. Among them, 7.5Fe-15Ni/MS₁₅Ca₈₅ exhibited the best catalytic performance, achieving a toluene conversion of 96.77%, an H₂ yield of approximately 77%, and stable operation for 45 h on stream. Characterization results suggest that appropriate Fe addition promoted the formation of Ni-Fe alloy species, improved the dispersion of active metal species, and optimized the pore structure, thereby increasing the accessibility of active sites. Moreover, Fe incorporation increased the relative proportion and potential reactivity of surface lattice oxygen species, which may facilitate the oxidation of carbonaceous intermediates and suppress coke accumulation. This study suggests that IBA can be upgraded into an effective support for Ni-based TSR catalysts and provides a feasible strategy for coupling solid-waste valorization with tar reforming for syngas production.