Production of nitrogen-free syngas (H₂ + CO) from CO₂ and NH₃

Abstract Towards the goal of carbon neutrality, future chemical production could utilize captured CO 2 as a carbon source instead of fossil carbon from petroleum or natural gas. However, the production of chemicals from CO 2 is highly energy-intense. The required energy could be imported to Japan in the form of hydrogen. However, the long-distance transport of molecular hydrogen is challenging. NH 3 has recently emerged as the most promising molecule for long-distance hydrogen transport and storage. The use of imported NH 3 as an energy vector to realize carbon recycling in the Japanese chemical industry is promising. Syngas (H 2 +CO) is an important intermediate in the production of chemicals and fuels from CO 2 . Hydrogen is required not only as a constituent of syngas, but also as a reductant of CO 2 . If hydrogen is imported in the form of NH 3 , conventionally, NH 3 would be cracked to H 2 and N 2 , the product gases and unconverted NH 3 separated, and CO/syngas then be produced through the reverse water gas shift reaction (RWGS). This conventional pathway is energy-intense and requires many unit operations. Here a novel process to produce nitrogen-free syngas directly, without producing molecular H 2 first and without any dedicated gas separation steps is presented. This is realized by a using a metal oxide bed material that is active for catalytic cracking of NH 3 , as well as able to transport oxygen through a redox reaction in a newly designed process. This leads to an inherent separation of N 2 . This process, referred to herein as “NH3-RWGS” has the potential to decrease costs and increase efficiency of syngas production from CO 2 and NH 3 .