Hierarchical Nanospheres with Polycrystalline Ir&Cu and Amorphous Cu2O toward Energy-Efficient Nitrate Electrolysis to Ammonia

Electrochemical reduction reaction of nitrate (NITRR) provides a sustainable route toward the green synthesis of ammonia. Nevertheless, it remains challenging to achieve high-performance electrocatalysts for NITRR especially at low overpotentials. In this work, hierarchical nanospheres consisting of polycrystalline Iridium&copper (Ir&Cu) and amorphous Cu₂O (Cu_xIr_yO_z NS) have been fabricated. The optimal species Cu_0.86Ir_0.14O_z delivers excellent catalytic performance with a desirable NH₃ yield rate (YR) up to 0.423 mmol h⁻¹ cm⁻² (or 4.8 mg h⁻¹ mg_cat⁻¹) and a high NH₃ Faradaic efficiency (FE) over 90% at a low overpotential of 0.69 V (or 0 V_RHE), where hydrogen evolution reaction (HER) is almost negligible. The electrolyzer toward NITRR and hydrazine oxidation (HzOR) is constructed for the first time with an electrode pair of Cu_0.86Ir_0.14O_z//Cu_0.86Ir_0.14O_z, yielding a high energy efficiency (EE) up to 87%. Density functional theory (DFT) calculations demonstrate that the dispersed Ir atom provides active site that not only promotes the NO₃⁻ adsorption but also modulates the H adsorption/desorption to facilitate the proton supply for the hydrogenation of *N, hence boosting the NITRR. This work thus points to the importance of both morphological/structural and compositional engineering for achieving the highly efficient catalysts toward NITRR.     

Microenvironment Engineering to Promote Selective Ammonia Electrosynthesis from Nitrate over a PdCu Hollow Catalyst

The electrosynthesis of recyclable ammonia (NH₃) from nitrate under ambient conditions is of great importance but still full of challenges for practical application. Herein, an efficient catalyst design strategy is developed that can engineer the surface microenvironment of a PdCu hollow (PdCu-H) catalyst to confine the intermediates and thus promote selective NH₃ electrosynthesis from nitrate. The hollow nanoparticles are synthesized by in situ reduction and nucleation of PdCu nanocrystals along a self-assembled micelle of a well-designed surfactant. The PdCu-H catalyst shows a structure-dependent selectivity toward the NH₃ product during the nitrate reduction reaction (NO₃⁻RR) electrocatalysis, enabling a high NH₃ Faradaic efficiency of 87.3% and a remarkable NH₃ yield rate of 0.551 mmol h⁻¹ mg⁻¹ at -0.30 V (vs reversible hydrogen electrode). Moreover, this PdCu-H catalyst delivers high electrochemical performance in the rechargeable zinc-NO₃⁻ battery. These results provide a promising design strategy to tune catalytic selectivity for efficient electrosynthesis of renewable NH₃ and feedstocks.     

Constructing Co@TiO2 Nanoarray Heterostructure with Schottky Contact for Selective Electrocatalytic Nitrate Reduction to Ammonia

Electrochemical nitrate (NO₃⁻) reduction reaction (NO₃⁻RR) is a potential sustainable route for large-scale ambient ammonia (NH₃) synthesis and regulating the nitrogen cycle. However, as this reaction involves multi-electron transfer steps, it urgently needs efficient electrocatalysts on promoting NH₃ selectivity. Herein, a rational design of Co nanoparticles anchored on TiO₂ nanobelt array on titanium plate (Co@TiO₂/TP) is presented as a high-efficiency electrocatalyst for NO₃⁻RR. Density theory calculations demonstrate that the constructed Schottky heterostructures coupling metallic Co with semiconductor TiO₂ develop a built-in electric field, which can accelerate the rate determining step and facilitate NO₃⁻ adsorption, ensuring the selective conversion to NH₃. Expectantly, the Co@TiO₂/TP electrocatalyst attains an excellent Faradaic efficiency of 96.7% and a high NH₃ yield of 800.0 µmol h⁻¹ cm⁻² under neutral solution. More importantly, Co@TiO₂/TP heterostructure catalyst also presents a remarkable stability in 50-h electrolysis test.     

Self-Supported Pd Nanorod Arrays for High-Efficient Nitrate Electroreduction to Ammonia

Electrochemical nitrate (NO₃⁻) reduction to ammonia (NH₃) offers a promising pathway to recover NO₃⁻ pollutants from industrial wastewater that can balance the nitrogen cycle and sustainable green NH₃ production. However, the efficiency of electrocatalytic NO₃⁻ reduction to NH₃ synthesis remains low for most of electrocatalysts due to complex reaction processes and severe hydrogen precipitation reaction. Herein, high performance of nitrate reduction reaction (NO₃⁻RR) is demonstrated on self-supported Pd nanorod arrays in porous nickel framework foam (Pd/NF). It provides a lot of active sites for H* adsorption and NO₃⁻ activation leading to a remarkable NH₃ yield rate of 1.52 mmol cm⁻² h⁻¹ and a Faradaic efficiency of 78% at −1.4 V versus RHE. Notably, it maintains a high NH₃ yield rate over 50 cycles in 25 h showing good stability. Remarkably, large-area Pd/NF electrode (25 cm²) shows a NH₃ yield of 174.25 mg h⁻¹, be promising candidate for large-area device for industrial application. In situ FTIR spectroscopy and density functional theory calculations analysis confirm that the enrichment effect of Pd nanorods encourages the adsorption of H species for ammonia synthesis following a hydrogenation mechanism. This work brings a useful strategy for designing NO₃⁻RR catalysts of nanorod arrays with customizable compositions.     

Constructing Ru@C3N4/Cu Tandem Electrocatalyst with Dual-Active Sites for Enhanced Nitrate Electroreduction to Ammonia

Electroreduction of nitrate to ammonia reaction (NO₃⁻RR) is considered as a promising carbon-free energy technique, which can eliminate nitrate from waste-water also produce value-added ammonia. However, it remains a challenge for achieving satisfied ammonia selectivity and Faraday efficiency (FE) due to the complex multiple-electron reduction process. Herein, a novel Tandem electrocatalyst that Ru dispersed on the porous graphitized C₃N₄ (g-C₃N₄) encapsulated with self-supported Cu nanowires (denoted as Ru@C₃N₄/Cu) for NO₃⁻RR is presented. As expected, a high ammonia yield of 0.249 mmol h⁻¹ cm⁻² at −0.9 V and high FE_NH3 of 91.3% at −0.8 V versus RHE can be obtained, while achieving excellent nitrate conversion (96.1%) and ammonia selectivity (91.4%) in neutral solution. In addition, density functional theory (DFT) calculations further demonstrate that the superior NO₃⁻RR performance is mainly resulted from the synergistic effect between the Ru and Cu dual-active sites, which can significantly enhance the adsorption of NO₃⁻ and facilitate hydrogenation, as well as suppress the hydrogen evolution reaction, thus lead to highly improved NO₃⁻RR performances. This novel design strategy would pave a feasible avenue for the development of advanced NO₃⁻RR electrocatalysts.     

N-Coordinated Cu–Ni Dual-Single-Atom Catalyst for Highly Selective Electrocatalytic Reduction of Nitrate to Ammonia

As a traditional method of ammonia (NH₃) synthesis, Haber–Bosch method expends a vast amount of energy. An alternative route for NH₃ synthesis is proposed from nitrate (NO₃⁻) via electrocatalysis. However, the structure–activity relationship remains challenging and requires in-depth research both experimentally and theoretically. Here an N-coordinated Cu–Ni dual-single-atom catalyst anchored in N-doped carbon (Cu/Ni–NC) is reported, which has competitive activity with a maximal NH₃ Faradaic efficiency of 97.28%. Detailed characterizations demonstrate that the high activity of Cu/Ni–NC mainly comes from the contribution of Cu–Ni dual active sites. That is, (1) the electron transfer (Ni → Cu) reveals the strong electron interaction of Cu–Ni dual-single-atom; (2) the strong hybridizations of Cu 3d—and Ni 3d—O 2p orbitals of NO₃⁻ can accelerate electron transfer from Cu–Ni dual-site to NO₃⁻; (3) Cu/Ni–NC can effectively decrease the rate-limiting step barriers, suppress N–N coupling for N₂O and N₂ formation and hydrogen production.     

Interfacially Engineered Nanoporous Cu/MnOx Hybrids for Highly Efficient Electrochemical Ammonia Synthesis via Nitrate Reduction

Electrochemical reduction of nitrate to ammonia (NH₃) not only offers a promising strategy for green NH₃ synthesis, but also addresses the environmental issues and balances the perturbed nitrogen cycle. However, current electrocatalytic nitrate reduction processes are still inefficient due to the lack of effective electrocatalysts. Here 3D nanoporous Cu/MnO_x hybrids are reported as efficient and durable electrocatalysts for nitrate reduction reaction, achieving the NH₃ yield rates of 5.53 and 29.3 mg h⁻¹ mg_cat.⁻¹ with 98.2% and 86.2% Faradic efficiency in 0.1 m Na₂SO₄ solution with 10 and 100 mm KNO₃, respectively, which are higher than those obtained for most of the reported catalysts under similar conditions. Both the experimental results and density functional theory calculations reveal that the interface effect between Cu/MnO_x interface could reduce the free energy of rate determining step and suppress the hydrogen evolution reaction, leading to the enhanced catalytic activity and selectivity. This work provides an approach to design advanced materials for NH₃ production via electrochemical nitrate reduction.     

Accelerating Industrial-Level NO3− Electroreduction to Ammonia on Cu Grain Boundary Sites via Heteroatom Doping Strategy

Although the electrocatalytic nitrate reduction reaction (NO₃⁻RR) is an attractive NH₃ synthesis route, it suffers from low yield due to the lack of efficient catalysts. Here, this work reports a novel grain boundary (GB)-rich Sn-Cu catalyst, derived from in situ electroreduction of Sn-doped CuO nanoflower, for effectively electrochemical converting NO₃⁻ to NH₃. The optimized Sn_1%-Cu electrode achieves a high NH₃ yield rate of 1.98 mmol h⁻¹ cm⁻² with an industrial-level current density of −425 mA cm⁻² at −0.55 V versus a reversible hydrogen electrode (RHE) and a maximum Faradaic efficiency of 98.2% at −0.51 V versus RHE, outperforming the pure Cu electrode. In situ Raman and attenuated total reflection Fourier transform infrared spectroscopies reveal the reaction pathway of NO₃⁻RR to NH₃ by monitoring the adsorption property of reaction intermediates. Density functional theory calculations clarify that the high-density GB active sites and the competitive hydrogen evolution reaction (HER) suppression induced by Sn doping synergistically promote highly active and selective NH₃ synthesis from NO₃⁻RR. This work paves an avenue for efficient NH₃ synthesis over Cu catalyst by in situ reconstruction of GB sites with heteroatom doping.     

Pd-Doped Co3O4 Nanoarray for Efficient Eight-Electron Nitrate Electrocatalytic Reduction to Ammonia Synthesis

Ammonia (NH₃) is an indispensable feedstock for fertilizer production and one of the most ideal green hydrogen rich fuel. Electrochemical nitrate (NO₃⁻) reduction reaction (NO₃⁻RR) is being explored as a promising strategy for green to synthesize industrial-scale NH₃, which has nonetheless involved complex multi-reaction process. This work presents a Pd-doped Co₃O₄ nanoarray on titanium mesh (Pd-Co₃O₄/TM) electrode for highly efficient and selective electrocatalytic NO₃⁻RR to NH₃ at low onset potential. The well-designed Pd-Co₃O₄/TM delivers a large NH₃ yield of 745.6 µmol h⁻¹ cm⁻² and an extremely high Faradaic efficiency (FE) of 98.7% at −0.3 V with strong stability. These calculations further indicate that the doping Co₃O₄ with Pd improves the adsorption characteristic of Pd-Co₃O₄ and optimizes the free energies for intermediates, thereby facilitating the kinetics of the reaction. Furthermore, assembling this catalyst in a Zn-NO₃⁻ battery realizes a power density of 3.9 mW cm⁻² and an excellent FE of 98.8% for NH₃.     

Au Nanowires Decorated Ultrathin Co3O4 Nanosheets toward Light-Enhanced Nitrate Electroreduction

Nitrate is a reasonable alternative instead of nitrogen for ammonia production due to the low bond energy, large water-solubility, and high chemical polarity for good absorption. Nitrate electroreduction reaction (NO₃RR) is an effective and green strategy for both nitrate treatment and ammonia production. As an electrochemical reaction, the NO₃RR requires an efficient electrocatalyst for achieving high activity and selectivity. Inspired by the enhancement effect of heterostructure on electrocatalysis, Au nanowires decorated ultrathin Co₃O₄ nanosheets (Co₃O₄-NS/Au-NWs) nanohybrids are proposed for improving the efficiency of nitrate-to-ammonia electroreduction. Theoretical calculation reveals that Au heteroatoms can effectively adjust the electron structure of Co active centers and reduce the energy barrier of the determining step (*NO → *NOH) during NO₃RR. As the result, the Co₃O₄-NS/Au-NWs nanohybrids achieve an outstanding catalytic performance with high yield rate (2.661 mg h⁻¹ mg_cat⁻¹) toward nitrate-to-ammonia. Importantly, the Co₃O₄-NS/Au-NWs nanohybrids show an obviously plasmon-promoted activity for NO₃RR due to the localized surface plasmon resonance (LSPR) property of Au-NWs, which can achieve an enhanced NH₃ yield rate of 4.045 mg h⁻¹ mg_cat⁻¹. This study reveals the structure–activity relationship of heterostructure and LSPR-promotion effect toward NO₃RR, which provide an efficient nitrate-to-ammonia reduction with high efficiency.     

Electrochemical Fabrication of Porous Au Film on Ni Foam for Nitrogen Reduction to Ammonia

Electrochemical reduction of N₂ to NH₃ provides an alternative strategy to replace the industrial Haber–Bosch process for facile and sustainable production of NH₃. The development of efficient electrocatalysts for the nitrogen reduction reaction (NRR) is highly desired. Herein, a micelle‐assisted electrodeposition method is presented for the direct fabrication of porous Au film on Ni foam (pAu/NF). Benefiting from its interconnected porous architectonics, the pAu/NF exhibits superior NRR performance with a high NH₃ yield rate of 9.42 µg h^?1 cm^?2 and a superior Faradaic efficiency of 13.36% at ?0.2 V versus reversible hydrogen electrode under the neutral electrolyte (0.1 m Na₂SO₄). The proposed micelle‐assisted electrodeposition strategy is highly valuable for future design of active NRR catalysts with desired compositions toward various electrocatalysis fields.     

Solvent Engineering of Oxygen-Enriched Carbon Dots for Efficient Electrochemical Hydrogen Peroxide Production

The development of cost-effective and reliable metal-free carbon-based electrocatalysts has gained significant attention for electrochemical hydrogen peroxide (H₂O₂) generation through a two-electron oxygen reduction reaction. In this study, a scalable solvent engineering strategy is employed to fabricate oxygen-doped carbon dots (O-CDs) that exhibit excellent performance as electrocatalysts. By adjusting the ratio of ethanol and acetone solvents during the synthesis, the surface electronic structure of the resulting O-CDs can be systematically tuned. The amount of edge active C O group was strongly correlated with the selectivity and activity of the O-CDs. The optimum O-CDs-3 exhibited extraordinary H₂O₂ selectivity of up to 96.55% (n = 2.06) at 0.65 V (vs RHE) and achieved a remarkably low Tafel plot of 64.8 mV dec⁻¹. Furthermore, the realistic H₂O₂ productivity yield of flow cell is measured to be as high as 111.18 mg h⁻¹ cm⁻² for a duration of 10 h. The findings highlight the potential of universal solvent engineering approach for enabling the development of carbon-based electrocatalytic materials with improved performance. Further studies will be undertaken to explore the practical implications of the findings for advancing the field of carbon-based electrocatalysis.     

Flexible Co–Mo–N/Au Electrodes with a Hierarchical Nanoporous Architecture as Highly Efficient Electrocatalysts for Oxygen Evolution Reaction

Designing highly active and robust electrocatalysts for oxygen evolution reaction (OER) is crucial for many renewable energy storage and conversion devices. Here, self-supported monolithic hybrid electrodes that are composed of bimetallic cobalt–molybdenum nitride nanosheets vertically aligned on 3D and bicontinuous nanoporous gold (NP Au/CoMoN_x) are reported as highly efficient electrocatalysts to boost the sluggish reaction kinetics of water oxidation in alkaline media. By virtue of the constituent CoMoN_x nanosheets having large accessible CoMoO_x surface with remarkably enhanced electrocatalytic activity and the nanoporous Au skeleton facilitating electron transfer and mass transport, the NP Au/CoMoN_x electrode exhibits superior OER electrocatalysis in 1 m KOH, with low onset overpotential (166 mV) and Tafel slope (46 mV dec⁻¹). It only takes a low overpotential of 370 mV to reach ultrahigh current density of 1156 mA cm⁻², ≈140-fold higher than free CoMoN_x nanosheets. The electrocatalytic performance makes it an attractive candidate as the OER catalyst in the water electrolysis.     

A Generalized Surface Chalcogenation Strategy for Boosting the Electrochemical N2 Fixation of Metal Nanocrystals

Electrocatalytic nitrogen reduction reaction (NRR) is a promising process relative to energy-intensive Haber–Bosch process. While conventional electrocatalysts underperform with sluggish paths, achieving dissociation of N₂ brings the key challenge for enhancing NRR. This study proposes an effective surface chalcogenation strategy to improve the NRR performance of pristine metal nanocrystals (NCs). Surprisingly, the NH₃ yield and Faraday efficiency (FE) (175.6 ± 23.6 mg h^–1 g^–1_Rh and 13.3 ± 0.4%) of Rh-Se NCs is significantly enhanced by 16 and 15 times, respectively. Detailed investigations show that the superior activity and high FE are attributed to the effect of surface chalcogenation, which not only can decrease the apparent activation energy, but also inhibit the occurrence of the hydrogen evolution reaction (HER) process. Theoretical calculations reveal that the strong interface strain effect within core@shell system induces a critical redox inversion, resulting in a rather low valence state of Rh and Se surface sites. Such strong correlation indicates an efficient electron-transfer minimizing NRR barrier. Significantly, the surface chalcogenation strategy is general, which can extend to create other NRR metal electrocatalysts with enhanced performance. This strategy open a new avenue for future NH₃ production for breakthrough in the bottleneck of NRR.     

Size-Defined Ru Nanoclusters Supported by TiO2 Nanotubes Enable Low-Concentration Nitrate Electroreduction to Ammonia with Suppressed Hydrogen Evolution

Anthropogenic nitrate pollution has an adverse impact on the environment and human health. As part of a sustainable nitrate management strategy, electrochemical denitrification is studied as an innovative strategy for nutrients recycling and recovering. It is, however, challenging to selectively electro-reduce nitrate with low-concentration for ammonia. Herein, the photo-deposition of size-defined Ru nanoclusters (NCs, average size: ≈1.66 nm) on TiO₂ nanotubes (NTs) is demonstrated, which show improved performance for nitrate-to-ammonia electroreduction with a maximum yield rate of ≈600 µg h⁻¹ cm⁻² and a faradic efficiency (FE) of > 90.0% across a broad range of potentials in comparison with electrodeposited Ru nanoparticles (NPs, average size: ≈23.78 nm) on TiO₂ NTs. Experimental and theoretical evidence further suggests the small-size Ru NCs with the intrinsically enhanced selectivity and activity because of the strong metal/substrate interaction and unsaturated coordination state. The findings highlight the size effect on Ru-based catalyst supported on metal oxides, a versatile catalytic model, which allows the regulation of hydrogen adsorption to favor ammonia production over the competing hydrogen evolution reaction.     

A Highly Efficient Metal-Free Electrocatalyst of F-Doped Porous Carbon toward N2 Electroreduction

N₂ electroreduction into NH₃ represents an attractive prospect for N₂ utilization. Nevertheless, this process suffers from low Faraday efficiency (FE) and yield rate for NH₃. In this work, a highly efficient metal-free catalyst is developed by introducing F atoms into a 3D porous carbon framework (F-doped carbon) toward N₂ electroreduction. At −0.2 V versus reversible hydrogen electrode (RHE), the F-doped carbon achieves the highest FE of 54.8% for NH₃, which is 3.0 times as high as that (18.3%) of pristine carbon frameworks. Notably, at −0.3 V versus RHE, the yield rate of F-doped carbon for NH₃ reaches 197.7 µg_NH3 mg⁻¹_cat. h⁻¹. Such a value is more than one order of magnitude higher than those of other metal-free electrocatalysts under the near-ambient conditions for NH₃ product to date. Mechanistic studies reveal that the improved performance in N₂ electroreduction for F-doped carbon originates from the enhanced binding strength of N₂ and the facilitated dissociation of N₂ into *N₂H. F bonding to C atom creates a Lewis acid site due to the different electronegativity between the F and C atoms. As such, the repulsive interaction between the Lewis acid site and proton H suppresses the activity of H₂ evolution reaction, thus enhancing the selectivity of N₂ electroreduction into NH₃.     

A General Strategy to Glassy M-Te (M = Ru,Rh, Ir) Porous Nanorods for Efficient Electrochemical N2 Fixation

Electrochemical conversion of nitrogen (N₂) into value-added ammonia (NH₃) is highly desirable yet formidably challenging due to the extreme inertness of the N₂ molecule, which makes the development of a robust electrocatalyst prerequisite. Herein, a new class of bullet-like M-Te (M = Ru, Rh, Ir) glassy porous nanorods (PNRs) is reported as excellent electrocatalysts for N₂ reduction reaction (NRR). The optimized IrTe₄ PNRs present superior activity with the highest NH₃ yield rate (51.1 µg h⁻¹ mg⁻¹_cat.) and Faraday efficiency (15.3%), as well as long-term stability of up to 20 consecutive cycles, making them among the most active NRR electrocatalysts reported to date. Both the N₂ temperature-programmed desorption and valence band X-ray photoelectron spectroscopy data show that the strong chemical adsorption of N₂ is the key for enhancing the NRR and suppressing the hydrogen evolution reaction of IrTe₄ PNRs. Density functional theory calculations comprehensively identify that the superior adsorption strength of IrTe₄ adsorptions originates from the synergistic collaboration between electron-rich Ir and the highly electroactive surrounding Te atoms. The optimal adsorption of both N₂ and H₂O in alkaline media guarantees the superior consecutive NRR process. This work opens a new avenue for designing high-performance NRR electrocatalysts based on glassy materials.     

Rational Construction of Heterostructured Cu3P@TiO2 Nanoarray for High-Efficiency Electrochemical Nitrite Reduction to Ammonia

Electroreduction of nitrite (NO₂⁻) to valuable ammonia (NH₃) offers a sustainable and green approach for NH₃ synthesis. Here, a Cu₃P@TiO₂ heterostructure is rationally constructed as an active catalyst for selective NO₂⁻-to-NH₃ electroreduction, with rich nanosized Cu₃P anchored on a TiO₂ nanoribbon array on Ti plate (Cu₃P@TiO₂/TP). When performed in the 0.1 m NaOH with 0.1 m NaNO₂, the Cu₃P@TiO₂/TP electrode obtains a large NH₃ yield of 1583.4 µmol h⁻¹ cm⁻² and a high Faradaic efficiency of 97.1%. More importantly, Cu₃P@TiO₂/TP also delivers remarkable long-term stability for 50 h electrolysis. Theoretical calculations indicate that intermediate adsorption/conversion processes on Cu₃P@TiO₂ interfaces are synergistically optimized, substantially facilitating the conversion of NO₂⁻-to-NH₃.     

Piezoelectricity regulated ohmic contact in M/BaTiO3 (M = Ru,Pd, Pt) for charge collision and hydrogen free radical production in ammonia electrosynthesis

Electrochemical nitrate reduction reaction (NO₃RR) is a promising alternative technique for NH₃ generation toward the energy-consuming Haber-Bosch process. Nevertheless, it remains hindered by the competitive hydrogen evolution reaction (HER). Herein, the piezoelectric effect of electron-rich BaTiO₃ with oxygen vacancies is introduced to promote NO₃RR performance. Combining with metal particles (Ru, Pd and Pt), the catalyst achieves a maximal Faradaic efficiency of 95.3% and NH₃ yield rate of 6.87 mg h⁻¹ mg_cat.⁻¹. Upon piezoelectricity, the interface between metal nanoparticles and BaTiO₃ is effectively modulated from Schottky contact to ohmic contact, which leads to unobstructed electron transfer. Abundant hydrogen radicals (·H) can be then produced from the collision between plentiful electrons and polar water molecules adsorbed on the polar surface. Such ·H can significantly facilitate the hydrogenation of reaction intermediates in NO₃RR. Meanwhile, this process suppresses the Volmer-Heyrovsky step, therefore inhibiting the HER within a wide range of external potential. This work suggests a new strategy for promoting the performance of multi-electron-involved catalytic reactions.     

P-Block Metal-Based Electrocatalysts for Nitrogen Reduction to Ammonia: A Minireview

Electrochemical nitrogen reduction reaction (NRR) to ammonia (NH₃) using renewable electricity provides a promising approach towards carbon neutral. What's more, it has been regarded as the most promising alternative to the traditional Haber-Bosch route in current context of developing sustainable technologies. The development of a class of highly efficient electrocatalysts with high selectivity and stability is the key to electrochemical NRR. Among them, P-block metal-based electrocatalysts have significant application potential in NRR for which possessing a strong interaction with the N 2p orbitals. Thus, it offers a good selectivity for NRR to NH₃. The density of state (DOS) near the Fermi level is concentrated for the P-block metal-based catalysts, indicating the ability of P-block metal as active sites for N₂ adsorption and activation by donating p electrons. In this work, we systematically review the recent progress of P-block metal-based electrocatalysts for electrochemical NRR. The effect of P-block metal-based electrocatalysts on the NRR activity, selectivity and stability are discussed. Specifically, the catalyst design, the nature of the active sites of electrocatalysts and some strategies for boosting NRR performance, the reaction mechanism, and the impact of operating conditions are unveiled. Finally, some challenges and outlooks using P-block metal-based electrocatalysts are proposed.