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

Abstract

Precise 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 [Fe x Co y (Pbpy) 9 (ox) 6 (H 2 O) 6 ][P 2 W 18 O 62 ]•3H 2 O (abbreviated as Fe x Co y MOF-P 2 W 18 ) 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, NH 3 yield rates of 47.04 µg h −1 mg cat. −1 and Faradaic efficiency of 31.56% by FeCoMOF-P 2 W 18 for e-NRR are significantly enhanced by a factor of 4 and 3, respectively, compared to the [Fe 0.5 Co 0.5 (Pbpy)(ox)] 2 •(Pbpy) 0.5 . The cyclic voltammetry curves, density functional theory calculations and in situ Fouriertransform infrared spectroscopy confirm that there is a directional electron channel from P 2 W 18 to the MOFs unit to accelerate the transfer of electrons. And the introduction of bimetals Fe and Co in the P 2 W 18 -based MOFs can reduce the energy of the *N 2 to *N 2 H step, thereby increasing the production of NH 3 . 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 NH 3 production for breakthrough in the bottleneck of e-NRR.

Highly Efficient Photocatalysts: Polyoxometalate Synthons Enable Tailored CdS–MoS2 Morphologies and Enhanced H2 Evolution

“…Polyoxometalates (POMs) possess various desirable properties, including stable structure, tunable size and anionic charge, controllable solubility in both organic and aqueous solvents, catalytic capability, electrical conductivity, luminescence, magnetism, antiviral properties, reversible redox activity, and semiconductor-like properties. − Most importantly, it can serve as a preassembled platform with multiple pretransition-metal sources and a fixed ratio of bimetallic sources under hydrothermal conditions. − …”

New pyrimidine-amide-tetrazole ligand derived polyoxometalate-based copper complexes as catalysts for sulfide-sulfoxide transformation and electrochemical sensors

“…6–10 Moreover, the POM-based metal–organic complexes (POMOCs) constructed with the original POMs not only have the advantages of POMs, but also avoid the disadvantages of being easily soluble and prone to aggregation, and the conductivity and stability are also improved. 11–15 Therefore, these materials exhibit huge potential in the catalysis field. For instance, An's group has reported two POMOCs based on Keggin-type POM anions, H 3 [Cu I 3 (L) 3 ] 2 [PMo 12 O 40 ]·4H 2 O and H 3 [Cu I 3 (L) 3 ] 2 [PW 12 O 40 ]·6H 2 O (HL = 4-(1 H -tetrazol-5-yl)pyridine), which can be used as heterogeneous catalysts for p -benzoquinone synthesis.…”

Construction of Five POM Compounds by Tuning Spacer Length and Piperazine/Morpholine Groups: Electrochemical Sensing Properties and Application on Capacitor Materials

“…In recent years, supercapacitors (SCs) as an efficient energy storage system have attracted more attention owing to their low cost, good durability, and high power. In the future, SCs are promising tools to meet urgent energy needs. , Electrochemical sensors have the advantages of simple operation, fast response time, low cost, and high sensitivity . POMs have immeasurable application value in the fields of SC and electrochemical sensors due to their unique structural characteristics and excellent electrochemical properties. , On the one hand, POMs show a variety of molecular structures and compositions, adjustable redox, and designability .…”

“…In the future, SCs are promising tools to meet urgent energy needs. 9,12 Electrochemical sensors have the advantages of simple operation, fast response time, low cost, and high sensitivity. 13 POMs have immeasurable application value in the fields of SC and electrochemical sensors due to their unique structural characteristics and excellent electrochemical properties.…”