K/Ni-modified porous catalysts from coal gasification fine slag for biomass tar steam reforming

One-step flotation–activation for CGFS-derived catalysts. • Ni- and K-modified catalysts show distinct reforming pathways. • Ni-based catalysts achieve high tar conversion (97.2%) with coke resistance. • K favors CH 4 formation while Ni enhances H 2 -rich syngas production. Efficient and stable catalysts are essential for biomass-tar reforming in sustainable biomass gasification systems that utilize low-cost solid waste feedstocks. In this study, coal gasification fine slag (CGFS) was processed by saline flotation to enrich the residual carbon fraction and remove ash content, yielding a support material with enhanced catalyst surface area and pore volume. Low-concentration saline flotation produced supports with greater specific surface areas (S BET ), while high-concentration saline flotation yielded catalysts with superior catalytic performance. Catalytic performance was primarily determined by the nature of the metal loading. Ni-loaded catalysts (Ni4) achieved higher tar-conversion rates and CO yields than K-loaded counterparts (K4), with substantially greater H 2 production. Conversely, K4 produced higher CH 4 yields than Ni4, attributable to enhanced high-temperature methanation leading to higher CH 4 selectivity, whereas Ni-based catalysts showed superior overall catalytic performance and anti-coking ability, attributable to their unique FeNi 3 alloy active centers. Furthermore, regeneration tests demonstrated that both Ni4 and K4 catalysts retained considerable tar conversion capability after three reaction–regeneration cycles, highlighting their potential for cyclic utilization. These results demonstrate the potential of CGFS as a low-cost tar conversion catalyst. Download: Download high-res image (462KB) Download: Download full-size image