Biomimetic CO oxidation below -100 °C by a nitrate-containing metal-free microporous system

CO oxidation is of importance both for inorganic and living systems. Transition and precious metals supported on various materials can oxidize CO to CO₂. Among them, few systems, such as Au/TiO₂, can perform CO oxidation at temperatures as low as -70 °C. Living (an)aerobic organisms perform CO oxidation with nitrate using complex enzymes under ambient temperatures representing an essential pathway for life, which enables respiration in the absence of oxygen and leads to carbonate mineral formation. Herein, we report that CO can be oxidized to CO₂ by nitrate at -140 °C within an inorganic, nonmetallic zeolitic system. The transformation of NO_x and CO species in zeolite as well as the origin of this unique activity is clarified using a joint spectroscopic and computational approach.