Efficient Electron Transfer from an Electron‐Reservoir Polyoxometalate to Dual‐Metal‐Site Metal‐Organic Frameworks for Highly Efficient Electroreduction of Nitrogen

Abstract

AbstractPrecise design and construction of catalysts with satisfied performance for ambient electrolytic nitrogen reduction reaction (e‐NRR) is extremely challenging. By in situ integrating an electron‐rich polyoxometalates (POMs) into stable metal organic frameworks (MOFs), five POMs‐based MOFs formulated as [FexCoy(Pbpy)9(ox)6(H2O)6][P2W18O62]·3H2O (abbreviated as FexCoyMOF‐P2W18) are created and directly used as catalysts for e‐NRR. Their electrocatalytic performances are remarkably improved thanks to complementary advantages and promising possibilities of MOFs and POMs. In particular, NH3 yield rates of 47.04 µg h−1 mgcat.−1 and Faradaic efficiency of 31.56% by FeCoMOF‐P2W18 for e‐NRR are significantly enhanced by a factor of 4 and 3, respectively, compared to the [Fe0.5Co0.5(Pbpy)(ox)]2·(Pbpy)0.5. The cyclic voltammetry curves, density functional theory calculations and in situ Fourier‐transform infrared spectroscopy confirm that there is a directional electron channel from P2W18 to the MOFs unit to accelerate the transfer of electrons. And the introduction of bimetals Fe and Co in the P2W18‐based MOFs can reduce the energy of the *N2 to *N2H step, thereby increasing the production of NH3. More importantly, this POM in situ embedding strategy can be extended to create other e‐NRR catalysts with enhanced performances, which opens a new avenue for future NH3 production for breakthrough in the bottleneck of e‐NRR.