Two-dimensional graphdiyne analogue containing Mo-coordinated porphyrin covalent organic framework as a high-performance electrocatalyst for nitrogen fixation

Graphdiyne (GDY), as a burgeoning two-dimensional (2D) material, is regarded as an excellent carbon support owing to its unique polyyne structure, but lack of active sites. Meanwhile, metalloporphyrins can anchor various metals as eminent catalytic center and have been extensively applied in various electrochemical reactions, including N-2 reduction reaction (NRR). Integrating metalloporphyrins connected by polyynes as GDY analogues may create facile and charming heterogeneous electrochemical catalysts by merging their complementary advantages and broad prospects. Herein, the electrocatalytic behaviors of a sequence of 2D metalloporphyrin-based GDY analogues connected by butadiyne (TM-PDYs, TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, and W, respectively) toward NRR have been investigated by employing first-principles calculations. The computations demonstrate that 2D Mo-PDY owns superior electrocatalytic property for N-2 fixation with an ultralow overpotential of 0.14 V via the preferred distal pathway among the 19 candidates, together with the capability of inhibiting the competing hydrogen evolution reaction (HER). This work not only puts forward an innovative idea based on multi-active components to realize attainable functional 2D lattices for the design of high-performance catalysts, but also promotes more experimental researches in this field to achieve sustainable NH3 production.