Numerical approach to evaluate performance of porous SiC5/4O3/2 as potential high temperature hydrogen gas sensor

Porous silicon oxycarbide (SiCO) is a novel class of nano-porous material with superior gas sensing performance. In this work, the amorphous porous structure of SiC5/4O3/2 is successfully reproduced by simulating the experimental etching process, and the gas sensing performance of porous SiCO at high temperature is investigated. The calculation results show porous SiC5/4O3/2 exhibits a much higher sensitivity towards H2 than CO, NO2 and acetone at 773 K. Compared with the other three gases, H2 absorbed system show shorter adsorption distance and more obvious increasing in density of states around Fermi level. Therefore, porous SiC5/4O3/2 shows a highly selective sensitivity toward H2 at high temperature. Moreover, our results show the Si–C/O units are the major sensing sites of H2 at high temperature, and the large diffusion coefficient of H2 in SiC5/4O3/2 is related to the fast response of porous SiCO gas sensor.