Low‐Coordinate Step Atoms via Plasma‐Assisted Calcinations to Enhance Electrochemical Reduction of Nitrogen to Ammonia

The electrochemical N₂ reduction reaction (NRR) is emerging as a promising alternative to the industrial Haber–Bosch process for distributed and modular production of NH₃. Nevertheless, developing high‐efficiency catalysts to simultaneously realize both high activity and selectivity for the development of a sustainable NRR is very critical but extremely challenging. Here, a unique plasma‐assisted strategy is developed to synthesize iridium diphosphide nanocrystals with abundant surface step atoms anchored in P,N‐codoped porous carbon nanofilms (IrP₂@PNPC‐NF), where the edges of the IrP₂ nanocrystals are extremely irregular, and the ultrathin PNPC‐NF possesses a honeycomb‐like macroporous structure. These characteristics ensure that IrP₂@PNPC‐NF delivers superior NRR performance with an NH₃ yield rate of 94.0 µg h^?1 mg^?1_cat. and a faradaic efficiency (FE) of 17.8%. Density functional theory calculations reveal that the unique NRR performance originates from the low‐coordinate step atoms on the edges of IrP₂ nanocrystals, which can lower the reaction barrier to improve the NRR activity and simultaneously inhibit hydrogen evolution to achieve a high FE for NH₃ formation. More importantly, such a plasma‐assisted strategy is general and can be extended to the synthesis of other high‐melting‐point noble‐metal phosphides (OsP₂@PNPC‐NF, Re₃P₄@PNPC‐NF, etc.) with abundant step atoms at lower temperatures.     

Electrochemical Ammonia Synthesis via Nitrogen Reduction Reaction on a MoS2 Catalyst: Theoretical and Experimental Studies

The discovery of stable and noble‐metal‐free catalysts toward efficient electrochemical reduction of nitrogen (N₂) to ammonia (NH₃) is highly desired and significantly critical for the earth nitrogen cycle. Here, based on the theoretical predictions, MoS₂ is first utilized to catalyze the N₂ reduction reaction (NRR) under room temperature and atmospheric pressure. Electrochemical tests reveal that such catalyst achieves a high Faradaic efficiency (1.17%) and NH₃ yield (8.08 × 10^?11 mol s^?1 cm^?1) at ?0.5 V versus reversible hydrogen electrode in 0.1 m Na₂SO₄. Even in acidic conditions, where strong hydrogen evolution reaction occurs, MoS₂ is still active for the NRR. This work represents an important addition to the growing family of transition‐metal‐based catalysts with advanced performance in NRR.     

Salt‐Templated Construction of Ultrathin Cobalt Doped Iron Thiophosphite Nanosheets toward Electrochemical Ammonia Synthesis

Exploiting efficient electrocatalysts for electrochemical nitrogen reduction (NRR) is highly desired and deeply meaningful for realizing sustainable ammonia (NH₃) production under ambient conditions. The Fe protein contains one [Fe₄S₄] cluster and P cluster, which play an important role for transfer electron during the nitrogen fixing of nitrogenases. Based on the understanding of nitrogenase, the rising‐star 2D iron thiophosphite (FePS₃) nanomaterials may be highly active electrocatalysts toward NRR due to the ideal elemental composition. In this work, 2D FePS₃ nanosheets are successfully synthesized by a facile salt‐templated method. The FePS₃ nanosheets show better electrocatalytic NH₃ yield and faradaic efficiency (FE) than Fe₂S₃, which demonstrates that the P element indeed improves the NRR activity of Fe‐S. Theoretically, Co incorporation not only effectively prompts the conductivity of FePS₃, but also enhances the catalytic activities of Fe‐edge sites. Experimentally, Co‐doped FePS₃ (Co‐FePS₃) nanosheets exhibit a remarkable electrocatalytic performance toward NRR, such as high NH₃ yield rate of 90.6 µg h^?1 mg_cat^?1, high FE of 3.38%, and an excellent long‐term stability. Being the first theoretical and experimental report regarding FePS₃‐based electrocatalyst toward NRR, this work represents an important beginning to the family of metal thiophosphite as advanced electrocatalysts toward NRR.     

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.     

B?N Pairs Enriched Defective Carbon Nanosheets for Ammonia Synthesis with High Efficiency

Electrochemical synthesis has garnered attention as a promising alternative to the traditional Haber–Bosch process to enable the generation of ammonia (NH₃) under ambient conditions. Current electrocatalysts for the nitrogen reduction reaction (NRR) to produce NH₃ are comprised of noble metals or transitional metals. Here, an efficient metal‐free catalyst (BCN) is demonstrated without precious component and can be easily fabricated by pyrolysis of organic precursor. Both theoretical calculations and experiments confirm that the doped B? N pairs are the active triggers and the edge carbon atoms near to B? N pairs are the active sites toward the NRR. This doping strategy can provide sufficient active sites while retarding the competing hydrogen evolution reaction (HER) process; thus, NRR with high NH₃ formation rate (7.75 µg h^?1 mg_cat. ^?1) and excellent Faradaic efficiency (13.79%) are achieved at ?0.3 V versus reversible hydrogen electrode (RHE), exceeding the performance of most of the metallic catalysts.     

Formation of B?N?C Coordination to Stabilize the Exposed Active Nitrogen Atoms in g‐C3N4 for Dramatically Enhanced Photocatalytic Ammonia Synthesis Performance

It is an important issue that exposed active nitrogen atoms (e.g., edge or amino N atoms) in graphitic carbon nitride (g‐C₃N₄) could participate in ammonia (NH₃) synthesis during the photocatalytic nitrogen reduction reaction (NRR). Herein, the experimental results in this work demonstrate that the exposed active N atoms in g‐C₃N₄ nanosheets can indeed be hydrogenated and contribute to NH₃ synthesis during the visible‐light photocatalytic NRR. However, these exposed N atoms can be firmly stabilized through forming B? N? C coordination by means of B‐doping in g‐C₃N₄ nanosheets (BCN) with a B‐doping content of 13.8 wt%. Moreover, the formed B? N? C coordination in g‐C₃N₄ not only effectively enhances the visible‐light harvesting and suppresses the recombination of photogenerated carriers in g‐C₃N₄, but also acts as the catalytic active site for N₂ adsorption, activation, and hydrogenation. Consequently, the as‐synthesized BCN exhibits high visible‐light‐driven photocatalytic NRR activity, affording an NH₃ yield rate of 313.9 µmol g^?1 h^?1, nearly 10 times of that for pristine g‐C₃N₄. This work would be helpful for designing and developing high‐efficiency metal‐free NRR catalysts for visible‐light‐driven photocatalytic NH₃ synthesis.     

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.     

Amorphous Sn/Crystalline SnS2 Nanosheets via In Situ Electrochemical Reduction Methodology for Highly Efficient Ambient N2 Fixation

Electrochemical nitrogen reduction reaction (NRR) as a new strategy for synthesizing ammonia has attracted ever‐growing attention, due to its renewability, flexibility, and sustainability. However, the lack of efficient electrocatalysts has hampered the development of such reactions. Herein, a series of amorphous Sn/crystalline SnS₂ (Sn/SnS₂) nanosheets by an L‐cysteine‐based hydrothermal process, followed by in situ electrochemical reduction, are synthesized. The amount of reduced amorphous Sn can be adjusted by selecting electrolytes with different pH values. The optimized Sn/SnS₂ catalyst can achieve a high ammonia yield of 23.8 µg h^?1 mg^?1, outperforming most reported noble‐metal NRR electrocatalysts. According to the electrochemical tests, the conversion of SnS₂ to an amorphous Sn phase leads to the substantial increase of its catalytic activity, while the amorphous Sn is identified as the active phase. These results provide a guideline for a rational design of low‐cost and highly active Sn‐based catalysts thus paving a wider path for NRR.     

A Cost‐Efficient Bifunctional Ultrathin Nanosheets Array for Electrochemical Overall Water Splitting

The design of cost‐efficient earth‐abundant catalysts with superior performance for the electrochemical water splitting is highly desirable. Herein, a general strategy for fabricating superior bifunctional water splitting electrodes is reported, where cost‐efficient earth‐abundant ultrathin Ni‐based nanosheets arrays are directly grown on nickel foam (NF). The newly created Ni‐based nanosheets@NF exhibit unique features of ultrathin building block, 3D hierarchical structure, and alloy effect with the optimized Ni₅Fe layered double hydroxide@NF (Ni₅Fe LDH@NF) exhibiting low overpotentials of 210 and 133 mV toward both oxygen evolution reaction and hydrogen evolution reaction at 10 mA cm^?2 in alkaline condition, respectively. More significantly, when applying as the bifunctional overall water splitting electrocatalyst, the Ni₅Fe LDH@NF shows an appealing potential of 1.59 V at 10 mA cm^?2 and also superior durability at the very high current density of 50 mA cm^?2.     

Synergistically Coupling Black Phosphorus Quantum Dots with MnO2 Nanosheets for Efficient Electrochemical Nitrogen Reduction Under Ambient Conditions

The electrochemical nitrogen reduction reaction (NRR) is a promising strategy of nitrogen fixation into ammonia under ambient conditions. However, the development of electrochemical NRR is highly bottlenecked by the expensive noble metal catalysts. As a representative 2D nonmetallic material, black phosphorus (BP) has the valence electron structure similar to nitrogen, which can effectively adsorb the inactive nitrogen molecule and activate its triple bond. In addition, the relatively weak hydrogen adsorption can restrict the competitive and vigorous hydrogen evolution reaction. Herein, ultrafine BP quantum dots (QDs) are prepared via liquid‐phase exfoliation and then assembled on catalytically active MnO₂ nanosheets through van der Waals interactions. The obtained BP QDs/MnO₂ catalyst demonstrates admirable synergetic effects in electrochemical NRR. The monodisperse BP QDs providing major activity manifest excellent ammonia production steadily with high selectivity, which benefits from the robust confinement of the BP QDs on the wrinkled MnO₂ nanosheets with decent activity. A high ammonia yield rate of 25.3 µg h^?1 mg_cat.^?1 and faradic efficiency of 6.7% can be achieved at ?0.5 V (vs RHE) in 0.1 m Na₂SO₄ electrolyte, which are dramatically superior to either component. The isotopic labelling and other control tests further exclude the external contamination possibility and attest the genuine activity.     

Silk‐Derived 2D Porous Carbon Nanosheets with Atomically‐Dispersed Fe‐Nx‐C Sites for Highly Efficient Oxygen Reaction Catalysts

Controlled synthesis of highly efficient, stable, and cost‐effective oxygen reaction electrocatalysts with atomically‐dispersed Me–N_x–C active sites through an effective strategy is highly desired for high‐performance energy devices. Herein, based on regenerated silk fibroin dissolved in ferric chloride and zinc chloride aqueous solution, 2D porous carbon nanosheets with atomically‐dispersed Fe–N_x–C active sites and very large specific surface area (≈2105 m² g^?1) are prepared through a simple thermal treatment process. Owing to the 2D porous structure with large surface area and atomic dispersion of Fe–N_x–C active sites, the as‐prepared silk‐derived carbon nanosheets show superior electrochemical activity toward the oxygen reduction reaction with a half‐wave potential (E_1/2) of 0.853 V, remarkable stability with only 11 mV loss in E_1/2 after 30 000 cycles, as well as good catalytic activity toward the oxygen evolution reaction. This work provides a practical and effective approach for the synthesis of high‐performance oxygen reaction catalysts towards advanced energy materials.     

Light Field-Enhanced Single-Site Cu Electrocatalyst for Nitrogen Fixation

Direct electrocatalytic reduction of N₂ to NH₃ under mild conditions is attracting considerable interests but still remains enormous challenges in terms of respect of intrinsic catalytic activity and limited electrocatalytic efficiency. Herein, a photo-enhanced strategy is developed to improve the NRR activity on Cu single atoms catalysts. The atomically dispersed Cu single atoms supported TiO₂ nanosheets (Cu SAs/TiO₂) achieve a Faradaic Efficiency (12.88%) and NH₃ yield rate (6.26 µg h⁻¹ mg_cat⁻¹) at −0.05 V versus RHE under the light irradiation field, in which NH₃ yield rate is fivefold higher than that under pure electrocatalytic nitrogen reduction reaction (NRR) process and is remarkably superior in comparison to most of the similar type electrocatalysts. The existence of external light field improves electron transfer ability between Cu O and Ti O, and thus optimizes the accumulation of surface charges on Cu sites, endowing more electrons involved in nitrogen fixation. This work reveals an atomic-scale mechanistic understanding of field effect-enhanced electrochemical performance of catalysts and it provides predictive guidelines for the rational design of photo-enhanced electrochemical N₂ reduction catalysts.     

Nitrogen Vacancies on 2D Layered W2N3: A Stable and Efficient Active Site for Nitrogen Reduction Reaction

Electrochemical nitrogen reduction reaction (NRR) under ambient conditions provides an avenue to produce carbon‐free hydrogen carriers. However, the selectivity and activity of NRR are still hindered by the sluggish reaction kinetics. Nitrogen Vacancies on transition metal nitrides are considered as one of the most ideal active sites for NRR by virtue of their unique vacancy properties such as appropriate adsorption energy to dinitrogen molecule. However, their catalytic performance is usually limited by the unstable feature. Herein, a new 2D layered W₂N₃ nanosheet is prepared and the nitrogen vacancies are demonstrated to be active for electrochemical NRR with a steady ammonia production rate of 11.66 ± 0.98 µg h^?1 mg_cata^?1 (3.80 ± 0.32 × 10^?11 mol cm^?2 s^?1) and Faradaic efficiency of 11.67 ± 0.93% at ?0.2 V versus reversible hydrogen electrode for 12 cycles (24 h). A series of ex situ synchrotron‐based characterizations prove that the nitrogen vacancies on 2D W₂N₃ are stable by virtue of the high valence state of tungsten atoms and 2D confinement effect. Density function theory calculations suggest that nitrogen vacancies on W₂N₃ can provide an electron‐deficient environment which not only facilitates nitrogen adsorption, but also lowers the thermodynamic limiting potential of NRR.     

Structure Engineering of MoS2 via Simultaneous Oxygen and Phosphorus Incorporation for Improved Hydrogen Evolution

Oxygen and phosphorus dual‐doped MoS₂ nanosheets (O,P‐MoS₂) with porous structure and continuous conductive network are fabricated using a one‐pot NaH₂PO₂‐assisted hydrothermal approach. By simply changing the precursor solution, the chemical composition and resulting structure can be effectively controlled to obtain desired properties toward the hydrogen evolution reaction (HER). Thanks to the beneficial structure and strong synergistic effects between the incorporated oxygen and phosphorus, the optimal O,P‐MoS₂ exhibit superior electrocatalytic performances compared with those of oxygen single‐doped MoS₂ nanosheets (O‐MoS₂). Specifically, a low HER onset overpotential of 150 mV with a small Tafel slope of 53 mV dec^?1, excellent conductivity, and long‐term durability are achieved by the structural engineering of MoS₂ via O and P co‐doping, making it an efficient HER electrocatalyst for water electrocatalysis. This work provides an alternative strategy to manipulate transition metal dichalcogenides as advanced materials for electrocatalytic and related energy applications.     

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.     

Au Sub‐Nanoclusters on TiO2 toward Highly Efficient and Selective Electrocatalyst for N2 Conversion to NH3 at Ambient Conditions

As the N?N bond in N₂ is one of the strongest bonds in chemistry, the fixation of N₂ to ammonia is a kinetically complex and energetically challenging reaction and, up to now, its synthesis is still heavily relying on energy and capital intensive Haber–Bosch process (150–350 atm, 350–550 °C), wherein the input of H₂ and energy are largely derived from fossil fuels and thus result in large amount of CO₂ emission. In this paper, it is demonstrated that by using Au sub‐nanoclusters (≈0.5 nm ) embedded on TiO₂ (Au loading is 1.542 wt%), the electrocatalytic N₂ reduction reaction (NRR) is indeed possible at ambient condition. Unexpectedly, NRR with very high and stable production yield (NH₃: 21.4 µg h^?1 mg^?1_cat., Faradaic efficiency: 8.11%) and good selectivity is achieved at ?0.2 V versus RHE, which is much higher than that of the best results for N₂ fixation under ambient conditions, and even comparable to the yield and activation energy under high temperatures and/or pressures. As isolated precious metal active centers dispersed onto oxide supports provide a well‐defined system, the special structure of atomic Au cluster would promote other important reactions besides NRR for water splitting, fuel cells, and other electrochemical devices.     

Highly Selective N2 Electroreduction to NH3 Using a Boron-Vacancy-Rich Diatomic Nb?B Catalyst

The ambient electrochemical N₂ reduction reaction (NRR) is a future approach for the artificial NH₃ synthesis to overcome the problems of high-energy consumption and environmental pollution by Haber–Bosch technology. However, the challenge of N₂ activation on a catalyst surface and the competitive hydrogen evolution reaction make the current NRR unsatisfied. Herein, this work demonstrates that NbB₂ nanoflakes (NFs) exhibit excellent selectivity and durability in NRR, which produces NH₃ with a production rate of 30.5 µg h⁻¹ mg_cat⁻¹ and a super-high Faraday efficiency (FE) of 40.2%. The high-selective NH₃ production is attributed to the large amount of active B vacancies on the surface of NbB₂ NFs. Density functional theory calculations suggest that the multiple atomic adsorption of N₂ on both unsaturated Nb and B atoms results in a significantly stretched N₂ molecule. The weakened NN triple bonds are easier to be broken for a biased NH₃ production. The diatomic catalysis is a future approach for NRR as it shows a special N₂ adsorption mode that can be well engineered.     

Co Nanoparticles Confined in 3D Nitrogen‐Doped Porous Carbon Foams as Bifunctional Electrocatalysts for Long‐Life Rechargeable Zn–Air Batteries

Proper design and simple preparation of nonnoble bifunctional electrocatalysts with high cost performance and strong durability for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) is highly demanded but still full of enormous challenges. In this work, a spontaneous gas‐foaming strategy is presented to synthesize cobalt nanoparticles confined in 3D nitrogen‐doped porous carbon foams (CoNCF) by simply carbonizing the mixture of citric acid, NH₄Cl, and Co(NO₃)₂·6H₂O. Thanks to its particular 3D porous foam architecture, ultrahigh specific surface area (1641 m² g^?1), and homogeneous distribution of active sites (C–N, Co–N_x, and Co–O moieties), the optimized CoNCF‐1000‐80 (carbonized at 1000 °C, containing 80 mg Co(NO₃)₂·6H₂O in precursors) catalyst exhibits a remarkable bifunctional activity and long‐term durability toward both ORR and OER. Its bifunctional activity parameter (ΔE) is as low as 0.84 V, which is much smaller than that of noble metal catalyst and comparable to state‐of‐the‐art bifunctional catalysts. When worked as an air electrode catalyst in rechargeable Zn–air batteries, a high energy density (797 Wh kg^?1), a low charge/discharge voltage gap (0.75 V), and a long‐term cycle stability (over 166 h) are achieved at 10 mA cm^?2.     

A Humidity‐Induced Nontemplating Route toward Hierarchical Porous Carbon Fiber Hybrid for Efficient Bifunctional Oxygen Catalysis

Hierarchical porous carbons (HPCs) are highly efficient supports for various remarkable catalytic systems. However, templates are commonly utilized for the preparation of HPCs, and the postremoval of the templates is uneconomical, time‐consuming, and harmful for the environment in most cases. Herein, a new humidity‐induced nontemplating strategy is developed to prepare 1D HPC with rich topologies and interconnected cavities for catalysis and energy storage applications. Porous electrospun nanofibers as calcination precursors are prepared via a humidity‐induced phase separation strategy. A nitrogen‐doped hierarchical porous carbon nanofiber (HPCNF), loading Co/Co₃O₄ hetero‐nanoparticles as exemplary nonprecious‐metal active substance (Co/Co₃O₄@HPCNF), is fabricated through the subsequent hydrothermal and pyrolysis treatment. The internal mesopore and cavity structure can be simply controlled by varying environment humidity during the electrospinning process. Benefiting from the unique topology, Co/Co₃O₄@HPCNF exhibits superior bifunctional activity when being used as electrocatalysts for oxygen reduction/evolution reactions. Moreover, the hybrid catalyst also demonstrates a remarkable power density of 102.5 mW cm^?2, a high capacity of 748.5 mAh g_Zn^?1, and long cycle life in Zinc–air batteries. The developed approach offers a facile template‐free route for the preparation of HPCNF hybrid and can be extended to other members of the large polymer family for catalyst design and energy storage applications.     

Controllable Exfoliation of MOF-Derived Van Der Waals Superstructure into Ultrathin 2D B/N Co-Doped Porous Carbon Nanosheets: A Superior Catalyst for Ambient Ammonia Electrosynthesis

The electrocatalytic nitrogen reduction reaction (NRR) to synthesize NH₃ under ambient conditions is a promising alternative route to the conventional Haber–Bosch process, but it is still a great challenge to develop electrocatalysts’ high Faraday efficiency and ammonia yield. Herein, a facile and efficient exfoliation strategy to synthesize ultrathin 2D boron and nitrogen co-doped porous carbon nanosheets (B/N C NS) via a metal–organic framework (MOF)-derived van der Waals superstructure, is reported. The results of experiments and theoretical calculations show that the doping of boron and nitrogen can modulate the electronic structure of the adjacent carbon atoms; which thus, promotes the competitive adsorption of nitrogen and reduces the energy required for ammonia synthesis. The B/N C NS exhibits excellent catalytic performance and stability in electrocatalytic NRR, with a yield rate of 153.4 µg·h⁻¹·mg⁻¹ cat and a Faraday efficiency of 33.1%, which is better than most of the reported NRR electrocatalysts. The ammonia yield of B/N C NS can maintain 92.7% of the initial NRR activity after 48 h stability test. The authors’ controllable exfoliation strategy using MOF-derived van der Waals superstructure can provide a new insight for the synthesis of other 2D materials.