Enhancing SO2 and NO2 Gas Sensing Using ZnCdO2‑Based Porous Nanosheets: A DFT Perspective

The exceptional electronic properties, high surface area, and structural versatility of two-dimensional materials make them excellent candidates for gas-sensing applications. In this study, we propose novel biphenylene (b) and graphenylene (g) lattices of ZnCdO2 and explore their potential for detecting NO2 and SO2 gases via density functional theory calculations. The dynamic and thermal stability of b-(g)-ZnCdO2 monolayers is confirmed through phonon dispersion and ab initio molecular dynamics simulations. Both gases exhibit favorable adsorption on the monolayers, with significant charge transfer and electronic interaction. Notably, SO2 interaction on g-ZnCdO2 is characterized by weak chemisorption, supported by moderate adsorption energy, long-range interaction, and clear surface bonding, suggesting reusability under ambient conditions. Gas adsorption also induces substantial modulation in the work function, reinforcing the suitability of these monolayers for work-function-type sensing. In particular, the g-ZnCdO2+SO2 system shows an ultrafast recovery time at room temperature, with improved desorption kinetics at elevated temperatures. These insights position b-(g)-ZnCdO2 monolayers as promising platforms for efficient and reusable toxic gas sensors.