A DFT study of superior adsorbate-surface bonding at Pt-WSe vertically aligned heterostructures upon NO, SO, CO, and H interactions.

This study investigates the potential of platinum (Pt) decorated single-layer WSe (Pt-WSe) monolayers as high-performance gas sensors for NO, CO, SO, and H using first-principles calculations. We quantify the impact of Pt placement (basal plane vs. vertical edge) on WSe's electronic properties, focusing on changes in bandgap (ΔE). Pt decoration significantly alters the bandgap, with vertical edge sites (T) exhibiting a drastic reduction (0.062 eV) compared to pristine WSe and basal plane decorated structures (T: 0.720 eV, T: 1.237 eV). This substantial ΔE reduction in T suggests a potential enhancement in sensor response. Furthermore, T displays the strongest binding capacity for all target gases due to a Pt-induced "spillover effect" that elongates adsorbed molecules. Specifically, T exhibits adsorption energies of - 0.5243 eV (NO), - 0.5777 eV (CO), - 0.8391 eV (SO), and - 0.1261 eV (H), indicating its enhanced sensitivity. Notably, H adsorption on T shows the highest conductivity modulation, suggesting exceptional H sensing capabilities. These findings demonstrate that Pt decoration, particularly along WSe vertical edges, significantly enhances gas sensing performance. This paves the way for Pt-WSe monolayers as highly selective and sensitive gas sensors for various applications, including environmental monitoring, leak detection, and breath analysis.