Tuning Main Group Element‐based Metal–Organic Framework to Boost Electrocatalytic Nitrogen Reduction Under Ambient Conditions

Abstract Main group element‐based materials are emerging catalysts for ammonia (NH₃) production via a sustainable electrochemical nitrogen reduction reaction (N₂RR) pathway under ambient conditions. However, their N₂RR performances are less explored due to the limited active behavior and unclear mechanism. Here, an aluminum‐based defective metal–organic framework (MOF), aluminum‐fumarate (Al‐Fum), is investigated. As a proof of concept, the pristine Al‐Fum MOF is synthesized by the solvothermal reaction process, and the defect engineering method namely solvent‐assisted linker exchange, is applied to create the defective Al sites. The defective Al sites play an important role in ensuring the N₂RR activity for defective Al‐Fum. It is found that only the defective Al‐Fum enables stable and effective electrochemical N₂RR, in terms of the highest production rate of 53.9 µg(NH₃) h⁻¹mg_cat⁻¹ (in 0.4 m K₂SO₄) and the Faradaic efficiency of 73.8% (in 0.1 m K₂SO₄) at −0.15 V vs reversible hydrogen electrode) under ambient conditions. Density functional theory calculations confirm that the N₂ activation can be achieved on the defective Al sites. Such sites also allow the subsequent protonation process via the alternating associative mechanism. This defect characteristic gives the main group Al‐based MOFs the ability to serve as promising electrocatalysts for N₂RR and other attractive applications.