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.     

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.     

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.     

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.     

Carbon‐Based Metal‐Free Catalysts for Electrocatalytic Reduction of Nitrogen for Synthesis of Ammonia at Ambient Conditions

The electrocatalytic nitrogen reduction reaction (NRR) is a promising catalytic system for N₂ fixation in ambient conditions. Currently, metal‐based catalysts are the most widely studied catalysts for electrocatalytic NRR. Unfortunately, the low selectivity and poor resistance to acids and bases, and the low Faradaic efficiency, production rate, and stability of metal‐based catalysts for NRR make them uncompetitive for the synthesis of ammonia in comparison to the industrial Haber–Bosch process. Inspired by applications of carbon‐based metal‐free catalysts (CMFCs) for the oxygen reduction reaction (ORR) and CO₂ reduction reaction (CO₂RR), the studies of these CMFCs in electrocatalytic NRR have attracted great attention in the past year. However, due to the differences in electrocatalytic NRR, there are several critical issues that need to be addressed in order to achieve rational design of advanced carbon‐based metal‐free electrocatalysts to improve activity, selectivity, and stability for NRR. Herein, the recent developments in the field of carbon‐based metal‐free NRR catalysts are presented, along with critical issues, challenges, and perspectives concerning metal‐free catalysts for electrocatalytic reduction of nitrogen for synthesis of ammonia at ambient conditions.     

Efficient Hydrogen Evolution Reaction Catalysis in Alkaline Media by All‐in‐One MoS2 with Multifunctional Active Sites

MoS₂ becomes an efficient and durable nonprecious‐metal electrocatalyst for the hydrogen evolution reaction (HER) when it contains multifunctional active sites for water splitting derived from 1T‐phase, defects, S vacancies, exposed Mo edges with expanded interlayer spacings. In contrast to previously reported MoS₂‐based catalysts targeting only a single or few of these characteristics, the all‐in‐one MoS₂ catalyst prepared herein features all of the above active site types. During synthesis, the intercalation of in situ generated NH₃ molecules into MoS₂ sheets affords ammoniated MoS₂ (A‐MoS₂) that predominantly comprises 1T‐MoS₂ and exhibits an expanded interlayer spacing. The subsequent reduction of A‐MoS₂ results in the removal of intercalated NH₃ and H₂S to form an all‐in‐one MoS₂ with multifunctional active sites mentioned above (R‐MoS₂) that exhibits electrocatalytic HER performance in alkaline media superior to those of all previously reported MoS₂‐based electrocatalysts. In particular, a hybrid MoS₂/nickel foam catalyst outperforms commercial Pt/C in the practically meaningful high‐current region (>25 mA cm^?2), demonstrating that R‐MoS₂‐based materials can potentially replace Pt catalysts in practical alkaline HER systems.     

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.     

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.     

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.     

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.     

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.     

Unveiling Active Sites for the Hydrogen Evolution Reaction on Monolayer MoS2

Here, the hydrogen evolution reaction (HER) activities at the edge and basal‐plane sites of monolayer molybdenum disulfide (MoS₂) synthesized by chemical vapor deposition (CVD) are studied using a local probe method enabled by selected‐area lithography. Reaction windows are opened by e‐beam lithography at sites of interest on poly(methyl methacrylate) (PMMA)‐covered monolayer MoS₂ triangles. The HER properties of MoS₂ edge sites are obtained by subtraction of the activity of the basal‐plane sites from results containing both basal‐plane and edge sites. The catalytic performances in terms of turnover frequencies (TOFs) are calculated based on the estimated number of active sites on the selected areas. The TOFs follow a descending order of 3.8 ± 1.6, 1.6 ± 1.2, 0.008 ± 0.002, and 1.9 ± 0.8 × 10^?4 s^?1, found for 1T′‐, 2H‐MoS₂ edges, and 1T′‐, 2H‐MoS₂ basal planes, respectively. Edge sites of both 2H‐ and 1T′‐MoS₂ are proved to have comparable activities to platinum (≈1–10 s^?1). When fitted into the HER volcano plot, the MoS₂ active sites follow a trend distinct from conventional metals, implying a possible difference in the reaction mechanism between transition‐metal dichalcogenides (TMDs) and metal catalysts.     

Roll‐to‐Roll Production of Layer‐Controlled Molybdenum Disulfide: A Platform for 2D Semiconductor‐Based Industrial Applications

A facile methodology for the large‐scale production of layer‐controlled MoS₂ layers on an inexpensive substrate involving a simple coating of single source precursor with subsequent roll‐to‐roll‐based thermal decomposition is developed. The resulting 50 cm long MoS₂ layers synthesized on Ni foils possess excellent long‐range uniformity and optimum stoichiometry. Moreover, this methodology is promising because it enables simple control of the number of MoS₂ layers by simply adjusting the concentration of (NH₄)₂MoS₄. Additionally, the capability of the MoS₂ for practical applications in electronic/optoelectronic devices and catalysts for hydrogen evolution reaction is verified. The MoS₂‐based field effect transistors exhibit unipolar n‐channel transistor behavior with electron mobility of 0.6 cm² V^?1 s^?1 and an on‐off ratio of ≈10³. The MoS₂‐based visible‐light photodetectors are fabricated in order to evaluate their photoelectrical properties, obtaining an 100% yield for active devices with significant photocurrents and extracted photoresponsivity of ≈22 mA W^?1. Moreover, the MoS₂ layers on Ni foils exhibit applicable catalytic activity with observed overpotential of ≈165 mV and a Tafel slope of 133 mV dec^?1. Based on these results, it is envisaged that the cost‐effective methodology will trigger actual industrial applications, as well as novel research related to 2D semiconductor‐based multifaceted applications.     

Interface Modulation of MoS2/Metal Oxide Heterostructures for Efficient Hydrogen Evolution Electrocatalysis

Developing efficient earth‐abundant MoS₂ based hydrogen evolution reaction (HER) electrocatalysts is important but challenging due to the sluggish kinetics in alkaline media. Herein, a strategy to fabricate a high‐performance MoS₂ based HER electrocatalyst by modulating interface electronic structure via metal oxides is developed. All the heterostructure catalysts present significant improvement of HER electrocatalytic activities, demonstrating a positive role of metal oxides decoration in promoting the rate‐limited water dissociation step for the HER mechanism in alkaline media. The as‐obtained MoS₂/Ni₂O₃H catalyst exhibits a low overpotential of 84 mV at 10 mA cm^?2 and small charge‐transfer resistance of 1.5 Ω in 1 m KOH solution. The current density (217 mA cm^?2) at the overpotential of 200 mV is about 2 and 24 times higher than that of commercial Pt/C and bare MoS₂, respectively. Additionally, these MoS₂/metal oxides heterostructure catalysts show outstanding long‐term stability under a harsh chronopotentiometry test. Theoretical calculations reveal the varied sensitivity of 3d‐band in different transition oxides, in which Ni‐3d of Ni₂O₃H is evidently activated to achieve fast electron transfer for HER as the electron‐depletion center. Both electronic properties and energetic reaction trends confirm the high electroactivity of MoS₂/Ni₂O₃H in the adsorption and dissociation of H₂O for highly efficient HER in alkaline media.     

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.     

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.     

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.     

Dendritic Cell‐Inspired Designed Architectures toward Highly Efficient Electrocatalysts for Nitrate Reduction Reaction

Electrocatalysis for nitrate reduction reaction (NRR) has recently been recognized as a promising technology to convert nitrate to nitrogen. Catalyst support plays an important role in electrocatalytic process. Although porous carbon and metal oxides are considered as common supports for metal‐based catalysts, fabrication of such architecture with high electric conductivity, uniform dispersion of nanoparticles, and long‐term catalytic stability through a simple and feasible approach still remains a significant challenge. Herein, inspired by the signal transfer mode of dendritic cell, an all‐carbon dendritic cell‐like (DCL) architecture comprising mesoporous carbon spheres (MCS) connected by tethered carbon nanotubes (CNTs) with CuPd nanoparticles dispersed throughout (CuPd@DCL‐MCS/CNTs) is reported. An impressive removal capacity as high as 22 500 mg N g^?1 CuPd (≈12 times superior to Fe‐based catalysts), high nitrate conversion (>95%) and nitrogen selectivity (>95%) are achieved under a low initial concentration of nitrate (100 mg L^?1) when using an optimized‐NRR electrocatalyst (4CuPd@DCL‐MCS/CNTs). Remarkably, nitrate conversion and nitrogen selectivity are both close to 100% in an ultralow concentration of 10 mg L^?1, meeting drinking water standard. The present work not only provides high electrocatalytic performance for NRR but also introduces new inspiration for the preparation of other DCL‐based architectures.     

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.     

Surface Engineering of MoS2 via Laser‐Induced Exfoliation in Protic Solvents

With excellent performance in the hydrogen evolution reaction (HER), molybdenum disulfide (MoS₂) is considered a promising nonprecious candidate to substitute Pt‐based catalysts. Herein, pulsed laser irradiation in liquid is used to realize one‐step exfoliation of bulk 2H‐MoS₂ to ultrastable few‐layer MoS₂ nanosheets. Such prepared MoS₂ nanosheets are rich in S vacancies and metallic 1T phase, which significantly contribute to the boosted catalytic HER activity. Protic solvents play a pivotal role in the production of S vacancies and 2H‐to‐1T phase transition under laser irradiation. MoS₂ exfoliated in an optimal solvent of formic acid exhibits outstanding HER activity with an overpotential of 180 mV at 10 mA cm^?2 and Tafel slope of 54 mV dec^?1.