Outdoor air pollution associated with climate change causes several million deaths per year. Gases produced by combustion processes and industrial plants are hazardous with limit values of the order of ppm (share per million) in terms of exposure level. Nitrogen dioxide NO2 plays a role in atmospheric reactions at the origin of acid rain, it contributes to the formation of “smog” and to the greenhouse effect. The detection and control of emissions of NO2 and carbon dioxide CO are essential to reduce their dangerous effects on the environment and humanity. In this project, the study of chemical interactions at the molecular scale is applied for the development of innovative devices. It is based on metal interaction (molecular metal complexes, metal nanoparticles, reactive metal surfaces) and strategic small reactive molecules (NO2, CO, H2, CO2, N2, NH3, etc.) either as a source of matter and/or energy or as a pollutant. This project is based on metal catalysis, resulting from the mastery of coordination chemistry, and whose general principles apply transversally to the field of chemical capture and sensors in the broad sense (detection, storage, release, control, quantification, depollution). In other words, ultra-sensitive sensor devices aim to be offered for the detection and control of toxic gases such as NO2 or CO.