Biomimetic CO Oxidation Below – 100 ⁰C by a Nitrate-Containing Metal-Free Microporous System

CO oxidation is of importance both for organic and inorganic systems. Transition and precious metals on various supports can oxidize CO to CO₂. Among them, few systems, like Au/TiO₂, can perform CO oxidation at the low temperature of -70 ⁰C. Living (an)aerobic organisms perform CO oxidation with nitrate using complex enzymes under ambient temperatures which is an important pathway of their living cycle that enables them to “breathe”/produce energy in the absence of oxygen and leads to the carbonate mineral formation. Herein, we report that CO can be oxidized to CO₂ by nitrate at –140 ⁰C in completely inorganic system (zeolite) without metals. The transformation of NO_x and CO species in zeolite as well as the origin of this unique activity (catalyzed by Bronsted acid sites) are clarified using spectroscopic and computational approach.