Design the transition metal dichalcogenides supported single-atom catalysts for electroreduction of nitrate to ammonia

Abstract

The development of electrocatalysts for nitrate reduction (NO₃RR) is crucial for sustainable ammonia production and environmental protection. This study theoretically screened transition metal dichalcogenides doped with single-atom transition metals to explore their NO₃RR activity, aiming to reveal the underlying factors affecting the NO₃RR performance. We identify *NO₃ adsorption energy ($\mathrm{\Delta }{E}_{{\mathrm{N}\mathrm{O}}_3}$$\mathrm{\Delta }{E}_{{\mathrm{N}\mathrm{O}}_3}$) as a key descriptor for NO₃RR activity and introduce φ, a descriptor combining metal d-electron number and electronegativity, for performance prediction. In-depth analysis revealed that NO₃ activation depends on the interaction between the metal’s d_xz/d_yz orbitals and the pz orbitals of the oxygen atoms in ${\mathrm{N}\mathrm{O}}_3^{-}$${\mathrm{N}\mathrm{O}}_3^{-}$, with $\mathrm{\Delta }{E}_{{\mathrm{N}\mathrm{O}}_3}$$\mathrm{\Delta }{E}_{{\mathrm{N}\mathrm{O}}_3}$ influencing the activity. Simultaneously, the descriptor φ captures the key factors governing $\mathrm{\Delta }{E}_{{\mathrm{N}\mathrm{O}}_3}$$\mathrm{\Delta }{E}_{{\mathrm{N}\mathrm{O}}_3}$. Based on these descriptors, Ni/WS₂ was identified as a promising candidate, showing high activity, selectivity, and stability for NO₃RR. This work provides valuable insights into the underlying factors driving NO₃RR activity, guiding the design of more efficient electrocatalysts.