Few-layered mesoporous graphene (FLMG) is employed as a sensing material to develop an innovative and high-sensitivity room temperature NO2 sensor through a simple manufacturing process. For this purpose, sensing material is optimized at 100 min by a high-energy milling process where natural graphite is used as a precursor: it is an inexpensive, sustainable and suitable active material. The large number of defects created and the enhanced degree of mesoporosity produced during the milling process determine the physical principles of operation of the designed device. NO2 gas sensing tests reveal an improved and selective performance with a change in resistance of ∼16 % at 0.5 ppm under ultraviolet photo-activation, establishing a detection limit around ∼25 ppb. Interestingly, the response of the developed sensor to humidity is independent in the measured range (0–33 % relative humidity at 25 °C) and the dependency to the presence of NH3 is rather poor as well (∼1.5 % at 50 ppm).
The authors acknowledge the Spanish Ministry of Science and Innovation for financing the projects RTI2018-095856-B-C22 (AEI/FEDER), RTI2018-095856-B-C21 (AEI/FEDER), RTI2018-095303-A-C52, MAT2015-65445-C2-1-R, MAT2017-86450-C4-1-R, MAT2015-67557-C2-1-P, and PIE 2010-6OE-013. The Comunidad de Madrid by S2018/NMT-4321. D. M. acknowledges the financial support from the Fundación General CSIC via Programa ComFuturo. A. S. acknowledges the financial support from the Comunidad de Madrid for an “Atracción de Talento Investigador” contract (no. 2017-t2/IND5395).