Silicon Oxycarbide-Derived Carbon as Potentia NO2 Gas Sensor: A First Principles' Study

Silicon oxycarbide (SiCO)-derived porous carbon is a novel class of nano-porous material with unique properties including highly sensitive gas detection. In this letter, SiCO-derived porous carbon (porous SiCO) structures are successfully reproduced by simulating the etching process in experiments. Then, the gas sensing performance of SiCO-derived carbon with different porous morphologies is investigated. The calculated adsorption energy, Mulliken charge transfer, bandgap, and adsorption distance indicate that SiCO-derived porous carbon exhibits a higher sensitivity toward NO2 gas than CO, H-2, and acetone in accordance with experimental conclusions. Moreover, the porous SiCO with the largest SSA and PV shows the most excellent NO2 sensing performance. The adsorption of NO2 leads to the appearance of a new strong peak at the edge of the conduction band, resulting in obvious changes of the conductivity of the systems, which is necessary for NO2 detection.