B-Power: Investigating the Upper Limits of Enhanced Surface Reactivity in Doped MoTe2

Abstract

Transition-metal dichalcogenide (TMD) monolayers have emerged as promising materials in electronics, gas sensing, and electrocatalysis. However, the limited chemical reactivity of TMD basal planes constrains their performance due to the lack of coordinatively unsaturated surface sites. Single-atom doping has shown potential to enhance TMD reactivity, though optimal doping strategies remain uncertain due to an incomplete understanding of the mechanisms and selectivity in reactivity enhancement. This study addresses this gap by investigating boron-doped MoTe₂ (B-MoTe₂)-the most active candidate identified in prior evaluations of 22 p-block elements. Using density functional theory (DFT) methods, we studied the adsorption behavior of 9 probe molecules: N₂O, NO₂, NO, N₂, CO₂, CO, O₂, H₂O, and H₂. Four distinct adsorption behaviors were identified: (i) dissociation of NO₂, O₂, and H₂, (ii) substitution of B by N for NO, (iii) chemisorption of N₂O, CO, and H₂O, and (iv) physisorption of N₂ and CO₂. These interactions are driven by the bonding affinity with boron and geometrical constraints of the sheet. The enhanced reactivity of B-MoTe₂ arises from boron adopting more favorable orbital hybridization during molecule adsorption, yielding adsorption strengths tens of times higher than those in pristine MoTe₂, where interactions are dominated by van der Waals forces. The unique physicochemical properties of B-MoTe₂ highlight the potential for tailored reactivity in catalysis and sensing applications and provide a foundational framework for developing effective doping strategies in TMD-based materials.