Photosynthesis of NH₃ from NO₃ ^- Using CH₄ in Homogenous Rhenium Catalysis

We present Re catalysis of one-pot synthesis of NH₃ from NO₃ ^- using CH₄ as a reductant under UV light irradiation at room temperature. NO₃ ^- leads to environmental issues such as water contamination, eutrophication, and biodiversity loss. In a natural system and a sewage facility, NO₃ ^- can be detoxified to N₂ using hydrogen donors by a microbial process. However, it is better to convert NO₃ ^- to NH₃ rather than N₂. To develop a desirable process of NO₃ ^- to NH₃ for a sustainable society, it is required that the reducing agent is derived from a renewable resource/energy. Thus, we turned our attention to CH₄, which has a high affinity with renewable resource/energy since it can be produced from livestock waste. Therefore, our system reported here is to directly convert NO₃ ^- to NH₃ using CH₄ with light energy.