Trace-level halogen blocks CO 2 emission in Fischer-Tropsch synthesis for olefins production
- Yi Cai
- Maolin Wang
- Shu Zhao
- Xi Liu
- Junzhong Xie
- Xing-Wu Liu
- Yao Xu
- Jie Zhang
- Lingzhen Zeng
- Fei Qian
- Zirui Gao
- Zeyan Cen
- Xingchen Liu
- Hong Wang
- Bingjun Xu
- Graham J. Hutchings
- Yong Yang
- Yong-Wang Li
- Xiao-Dong Wen
- Ding Ma
2025-10-30
Sustainable production of fuels and olefins from syngas (carbon monoxide and hydrogen) through the Fischer-Tropsch synthesis process requires catalysts that deliver high selectivity, industrial productivity, and minimal carbon dioxide (CO 2 ) emissions. Current industrial iron catalysts form substantial CO 2 by-product that limits carbon efficiency. We report that introducing trace amounts [parts per million (ppm) level] of halogen-containing compounds into the feed gas can suppress CO 2 formation using iron-based catalysts and boost olefin selectivity over paraffin and olefin productivity. Cofeeding 20 ppm bromomethane over an iron carbide catalyst decreased CO 2 selectivity to <1% and increased olefin selectivity to ~85% among all carbon-containing products. Surface-bound halogens modulated the catalyst surface structure and selectively inhibited pathways responsible for CO 2 generation and olefin hydrogenation. This strategy provides a simple, scalable, and broadly applicable route for carbon-efficient syngas conversion.