Iridium boosts the selectivity and stability of cobalt catalysts for syngas to liquid fuels

Summary

The industrial-relevant cobalt catalysts are usually promoted by a noble metal in Fischer-Tropsch synthesis, a key technology for production of synthetic fuels from various carbon resources (biomass, shale gas, and coal) via syngas (a mixture of hydrogen and carbon monoxide), but the function of noble metals remains controversial, hindering the design of high-performance and cost-effective catalysts. Here, we report that some noble metals, which can stabilize the active hexagonal close-packed phase of cobalt nanoparticles, facilitate the CO conversion and the formation of long-chain hydrocarbons. As the most representative promoter, iridium modulates geometric and electronic structures of cobalt surfaces, thus facilitating the CO dissociation and increasing the barrier for methane formation and the resistance to cobalt oxidation. The fabrication of iridium-cobalt single-atom alloy nanoparticles offers high CO conversion activity and about 95% selectivity of long-chain hydrocarbons with methane selectivity suppressed to lower than 3%, as well as ultrahigh stability over 1,300 h.