Researchers Slash CO2 Emissions in Fuel Synthesis by 99%

Scientists have achieved a remarkable breakthrough in reducing carbon dioxide emissions during the conversion of synthesis gas (syngas) into liquid fuels, cutting CO2 production by over 99%. A study led by researchers from China, published in the journal Science on November 4, 2025, reveals that the strategic addition of bromomethane (CH3Br) to syngas in the Fischer–Tropsch synthesis (FTS) process significantly enhances environmental performance.

The FTS process is pivotal in the petrochemical industry, converting syngas—a mixture of carbon monoxide (CO) and hydrogen (H2)—into liquid hydrocarbons. Traditionally, this method has been associated with substantial CO2 emissions, often ranging from 18% to 35% during production. The innovative approach introduced by the research team not only minimizes CO2 selectivity to near zero but also increases the yield of olefins, valuable hydrocarbons that are essential in various chemical applications.

By incorporating trace amounts of bromomethane into the syngas feed, the researchers altered the reaction dynamics on iron-based catalysts. This method resulted in an impressive olefin selectivity of 85%, accompanied by a notable olefin-to-paraffin ratio of 13:1—an improvement from the previous ratio of 1.3:1 with unmodified catalysts.

Transforming the Fischer–Tropsch Synthesis Process

The FTS process was developed in the 1920s by German chemists Franz Fischer and Hans Tropsch, gaining prominence during World War II as it provided critical liquid fuels for military operations. Today, iron-based catalysts dominate the FTS landscape, producing approximately 15.70 million tons of hydrocarbons annually. Their affordability and natural abundance make them a preferred choice, but they also tend to catalyze unwanted reactions that generate excess CO2.

Previous attempts to reduce CO2 emissions included coating iron catalysts with hydrophobic materials or graphene layers, which only yielded limited improvements. The new study’s approach circumvents these issues by forming surface-bound bromine species that effectively inhibit the water-gas shift and Boudouard reactions, both of which produce CO and CO2 as byproducts. This advancement not only mitigates CO2 output but also facilitates the release of olefins from the catalyst surface, preventing further hydrogenation into less desirable products.

Implications for Sustainable Energy

The researchers emphasize that this practical strategy can be integrated with a wide variety of iron-based FTS catalysts, including those used commercially. By enabling a carbon-neutral conversion pathway for coal and syngas, this research provides a crucial link between fossil fuel chemistry and climate sustainability.

As the world continues to shift toward greener energy technologies, fossil fuels still constitute over 80% of global energy consumption. Enhancing the efficiency of existing fossil fuel processes is essential for reducing their environmental impact. This study represents a significant step forward in making the FTS process not only more sustainable but also more compatible with future energy needs.

The long-term stability of the modified catalyst, which performed efficiently for over 450 hours, indicates its potential for real-world applications. By addressing the pressing challenge of CO2 emissions in fuel synthesis, these findings mark a pivotal advancement in the quest for more sustainable energy solutions.

This report was authored by Sanjukta Mondal, edited by Sadie Harley, and fact-checked by Robert Egan, ensuring a comprehensive and reliable exploration of this significant scientific development.