Semi-industrial CO and CO2 conversion with biochar-supported Fe-based catalysts

Abstract

• Iron-based catalysts supported on carbonaceous materials and promoted with Co, K, and/or Zn were evaluated for CO and CO 2 hydrogenation to gasoline-range hydrocarbons. • Biochar support outperformed commercial activated carbon, by reducing CH 4 selectivity and increasing C 5+ hydrocarbon production. • A conversion rate of 97% was achieved in CO hydrogenation. • Zinc promotion played a key role in boosting higher-chain hydrocarbon production. • A stability test confirmed that ZFCK@C maintains stable activity after 100 h of reaction. This research investigates the use of biochar derived from agricultural waste as a support material for Fe-based (Fe-Co-K) catalysts, with and without Zn, in CO and CO 2 hydrogenation, benchmarking its performance against commercial activated carbon. Under semi-industrial Fischer-Tropsch conditions, biochar-supported catalysts, particularly the Zn-enhanced variant (ZFCK@C), delivered superior catalytic outcomes. The catalysts were prepared using ultrasound-assisted dissolution and incipient wetness methods and characterized using FTIR, XRD, BET, H 2 -TPR, CO 2 -TPD, XPS, and TEM. In CO hydrogenation at 340 °C and 20 bar, ZFCK@C achieved a remarkable 97 % conversion, with 32 % longer hydrocarbons selectivity (C 5+ ), 39.6 % olefins distribution(C 5+ ), an O/P ratio of 4.0, and 45.3 % gasoline-range (C 5 –C 12 ) hydrocarbons distribution. For CO 2 hydrogenation at 340 °C and 30 bar, the catalyst showed 40 % conversion, low CH 4 selectivity (6.1 %), high C 5+ selectivity (45 %), 38.7 % olefins distribution(C 5+ ), an O/P ratio of 3.2, and 45.3 % kerosene-range (C 6 –C 16 ) hydrocarbons distribution. Stability testing over 100 h demonstrated excellent durability with no significant deactivation or sintering, making the catalyst viable for extended industrial use