Room-temperature self-cleaning molecular sensing by catalytic reactions

New sensing techniques using self-cleaning nanosensors for molecular detection are in demand. Here we describe a room-temperature process in which a nanostructured substrate catalyzes the reaction of a target molecule with atmospheric oxygen and the reaction energy is absorbed by the substrate, where it can in principle be detected. Specifically, we report first-principles calculations describing a reaction catalyzed by Fe-porphyrin at room temperature that breaks O$_{2}$, incorporates an oxygen into the methyl group of 2,4-dinitrotoluene (DNT) and releases 1.9 eV per reaction. The atomic oxygen left on the Fe site can be removed by reacting with another DNT molecule, making the whole process self-cleaning. The reaction energy absorbed by the substrate can in principle be detected optically, as for example, by detecting the metal-insulator phase transition in VO$_{2}$. We further explore issues of sensitivity and selectivity in exploiting this reaction for solid-state molecular sensing.