Enhanced NH₃ and NO₂ Sensing via Pd Decoration on WSeTe Janus Monolayers: A DFT Investigation

This study uses first‐principles calculation to investigate the potential of palladium (Pd)‐decorated single‐layer WSeTe (Pd‐WSeTe) as high‐performance gas sensors for NH₃ and NO₂. The impact of Pd placement (SeWTe‐TH, SeWTe‐TSe, SeWTe‐TW, TeWSe‐TH, TeWSe‐TTe, and TeWSe‐TW) is quantified on WSeTe's electronic properties, focusing on the changes in bandgap (ΔEg). Pd decoration significantly alters the bandgap, with SeWTe‐TH exhibiting a drastic reduction (0.115 eV) compared to pristine WSeTe (1.335 eV). This substantial ΔEg reduction in SeWTe‐TH suggests a potential enhancement in sensor response. Furthermore, SeWTe‐TSe displays the strongest binding capacity for targeted gases NH₃ and NO₂. SeWTe‐TSe exhibits adsorption energy of −1.693 eV (NO₂) and −1.517 eV (NH₃), indicating its enhanced sensitivity and exceptional NO₂ sensing capability. These results show that the performance of gas sensing is much improved by Pd decoration, especially along SeWTe‐TSe (NO₂). This makes the Pd‐WSeTe Janus monolayer a highly sensitive and selective gas sensor that may be used for several tasks, such as breath analysis, leak detection, and environmental monitoring.