A DFT study of superior adsorbate-surface bonding at Pt-WSe₂ vertically aligned heterostructures upon NO₂, SO₂, CO₂,...

This study investigates the potential of platinum (Pt) decorated single-layer WSe₂ (Pt-WSe₂) monolayers as high-performance gas sensors for NO₂, CO₂, SO₂, and H₂ using first-principles calculations. We quantify the impact of Pt placement (basal plane vs. vertical edge) on WSe₂'s electronic properties, focusing on changes in bandgap (ΔE_g). Pt decoration significantly alters the bandgap, with vertical edge sites (T_V-WSe2) exhibiting a drastic reduction (0.062 eV) compared to pristine WSe₂ and basal plane decorated structures (T_BH: 0.720 eV, T_BM: 1.237 eV). This substantial ΔE_g reduction in T_V-WSe2 suggests a potential enhancement in sensor response. Furthermore, T_V-WSe2 displays the strongest binding capacity for all target gases due to a Pt-induced "spillover effect" that elongates adsorbed molecules. Specifically, T_V-WSe2 exhibits adsorption energies of - 0.5243 eV (NO₂), - 0.5777 eV (CO₂), - 0.8391 eV (SO₂), and - 0.1261 eV (H₂), indicating its enhanced sensitivity. Notably, H₂ adsorption on T_V-WSe2 shows the highest conductivity modulation, suggesting exceptional H₂ sensing capabilities. These findings demonstrate that Pt decoration, particularly along WSe₂ vertical edges, significantly enhances gas sensing performance. This paves the way for Pt-WSe₂ monolayers as highly selective and sensitive gas sensors for various applications, including environmental monitoring, leak detection, and breath analysis.