Highly selective CO2Gas sensing properties of CaO-BaTiO3Heterostructures effectuated through discretely created n-n nanointerfaces

Globally recognized for its role as an occupational hazard, carbon dioxide (CO 2 ) detection and monitoring is essential in agriculture, chemical manufacturing, and healthcare/clinical-oriented applications. Although, optical and chemical gas sensors are available commercially, current gas sensing technologies involving selective monitoring of CO 2 at lower detection limits specifically for industrial conditions still remains a formidable challenge. Herein, we present a simple strategy for highly selective CO 2 detection using an inexpensive transducer platform based on reversible chemisorbed carbonation between CO 2 and CaO-BaTiO 3 heterostructures. Microsensors showed an optimum sensitivity of 65% toward 1000 ppm of CO 2 gas and superior selectivity when operated at 160 °C. Such a remarkable sensing performance originates from the discretely created n-n nanointerfaces and conveniently actualized staggered energy band positions that promote favorable charge transfer upon exposure to CO 2 gas molecules even at parts per million levels. Reversible sensing phenomenon is demonstrated using operando time-resolved diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and correlated with energy band alignment determined from the ultraviolet diffuse reflectance (UV-DRS) spectra to propose the sensing mechanism