Design of 3d transition metal anchored B₅N₃ catalysts for electrochemical CO₂ reduction to methane

Carbon dioxide (CO₂) reduction to value-added fuels and chemicals by making full use of the electricity generated from clean energy is promising to address environmental pollution and the energy crisis. However, the poor product selectivity at a low overpotential significantly hinders the large-scale use of catalysts. Herein, we provide a design guideline toward CO₂ selective reduction to methane (CH₄) by analyzing ten single-atom 3d transition metals (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) anchored on a B₅N₃ monolayer and screening favorable CO₂ electrocatalytic reduction pathways using spin-polarized density functional theory calculations with van der Waals corrections. Our results show that single-atom Ni anchored at the B₅N₃ monolayer (Ni@B₅N₃) exhibits good stability and electrical conductivity due to the hybrid orbitals at the Fermi level caused by doping. This designed catalyst possesses a high theoretical CH₄ selectivity and a considerably low limiting-potential (-0.21 V vs. reversible hydrogen electrode) for CO₂ electrocatalytic reduction to methane, in which the conversion of *CH₃ to *CH₄ is the potential-determining step. This study not only broadens the potential applications of B₅N₃ but also motivates experimental efforts to use single-atom catalysts for converting CO₂ to value-added hydrocarbons.