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Abstract Sodium‐storage performance of pyrite FeS2 is greatly improved by constructing various FeS2‐based nanostructures to optimize its ion‐transport kinetics and structural stability. However, less attention has been paid to rapid capacity degradation and electrode failure caused by the irreversible phase‐transition of intermediate NaxFeS2 to FeS2 and polysulfides dissolution upon cycling. Under the guidance of theoretical calculations, coupling FeS2 nanoparticles with honeycomb‐like nitrogen‐doped carbon (NC) nanosheet supported single‐atom manganese (SAs Mn) catalyst (FeS2/SAs Mn@NC) via atomic‐interface engineering is proposed to address above challenge. Systematic electrochemical analyses and theoretical results unveil that the functional integration of such two type components can significantly enhance ionic conductivity, accelerate charge transfer efficiency, and improve Na+‐adsorption capability. Particularly, SAs Mn@NC with Mn‐Nx coordination center can reduce the decomposition barrier of Na2S and NaxFeS2 to further accelerate reversible phase transformation of Fe/Na2S→NaFeS2→FeS2 and polysulfides decomposition. As predicted, such FeS2/SAs Mn@NC showcases outstanding rate capability and fascinating cyclic durability. A sequence of kinetic studies and ex situ characterizations provide the comprehensive understanding for ion‐transport kinetics and phase‐transformation process. Its practical use is further demonstrated in sodium‐ion full cell and capacitor with impressive electrochemical capability and excellent energy‐density output.

Abstract Electrocatalytic H2 production from seawater, recognized as a promising technology utilizing offshore renewables, faces challenges from chloride-induced reactions and corrosion. Here, We introduce a catalytic surface where OH– dominates over Cl– in adsorption and activation, which is crucial for O2 production. Our NiFe-based anode, enhanced by nearby Cr sites, achieves low overpotentials and selective alkaline seawater oxidation. It outperforms the RuO2 counterpart in terms of lifespan in scaled-up stacks, maintaining stability for over 2500 h in three-electrode tests. Ex situ/in situ analyses reveal that Cr(III) sites enrich OH–, while Cl– is repelled by Cr(VI) sites, both of which are well-dispersed and close to NiFe, enhancing charge transfer and overall electrode performance. Such multiple effects fundamentally boost the activity, selectively, and chemical stability of the NiFe-based electrode. This development marks a significant advance in creating durable, noble-metal-free electrodes for alkaline seawater electrolysis, highlighting the importance of well-distributed catalytic sites.

Abstract It is vital to explore effective ways for prolonging electrode lifespans under harsh electrolysis conditions, such as high current densities, acid environment, and impure water source. Here we report alternating electrolysis approaches that realize promptly and regularly repair/maintenance and concurrent bubble evolution. Electrode lifespans are improved by co-action of Fe group elemental ions and alkali metal cations, especially a unique Co2+-Na+ combo. A commercial Ni foam sustains ampere-level current densities alternatingly during continuous electrolysis for 93.8 h in an acidic solution, whereas such a Ni foam is completely dissolved in ~2 h for conventional electrolysis conditions. The work not only explores an alternating electrolysis-based system, alkali metal cation-based catalytic systems, and alkali metal cation-based electrodeposition techniques, and beyond, but demonstrates the possibility of prolonged electrolysis by repeated deposition-dissolution processes. With enough adjustable experimental variables, the upper improvement limit in the electrode lifespan would be high.

Abstract Exploring excellent non‐noble bifunctional electrocatalysts for freshwater/seawater splitting at high current densities has attracted extensive interest owing to strong anodic oxidation and severe chloride corrosion challenges. Herein, hierarchical bimetal Ni‐Co metaphosphate/molybdenum oxide heterostructure nanowires (NiCoMoPO) are rationally designed and fabricated to efficiently boost oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline freshwater/seawater, where the favorable electronic structure from heterostructures, signified by X‐ray absorption spectra, endows NiCoMoPO with the enhanced intrinsic activity, while its hierarchical nanowire structure and heterostructures provide abundant active sites. Additionally, the PO3− improves the chloride‐corrosion resistance and efficiently facilitates the OER kinetics verified by theoretical and experimental studies. Therefore, NiCoMoPO drives 1000 mA cm−2 at low overpotentials of 467 and 442 mV for OER and HER in alkaline freshwater respectively, as well as a small cell voltage of 2.135 V for overall freshwater splitting with robust durability of 300 h. Impressively, due to the strong corrosion resistance, at 500 mA cm−2 of overall seawater splitting, NiCoMoPO maintains almost 2.096 V for 1200 h, indicating promising practical applications. This work sheds light on the rational design and fabrication of outstanding electrocatalysts at high current densities of seawater/freshwater splitting.

Abstract Seawater electroreduction is attractive for future H2 production and intermittent energy storage, which has been hindered by aggressive Mg2+/Ca2+ precipitation at cathodes and consequent poor stability. Here we present a vital microscopic bubble/precipitate traffic system (MBPTS) by constructing honeycomb-type 3D cathodes for robust anti-precipitation seawater reduction (SR), which massively/uniformly release small-sized H2 bubbles to almost every corner of the cathode to repel Mg2+/Ca2+ precipitates without a break. Noticeably, the optimal cathode with built-in MBPTS not only enables state-of-the-art alkaline SR performance (1000-h stable operation at –1 A cm−2) but also is highly specialized in catalytically splitting natural seawater into H2 with the greatest anti-precipitation ability. Low precipitation amounts after prolonged tests under large current densities reflect genuine efficacy by our MBPTS. Additionally, a flow-type electrolyzer based on our optimal cathode stably functions at industrially-relevant 500 mA cm−2 for 150 h in natural seawater while unwaveringly sustaining near-100% H2 Faradic efficiency. Note that the estimated price (~1.8 US$/kgH2) is even cheaper than the US Department of Energy’s goal price (2 US$/kgH2).

Abstract The development of highly efficient sodium‐ion batteries depends critically on the successful exploitation of advanced anode hosts that is capable of overcoming sluggish reaction kinetics while also withstanding severe structural deformation triggered by the large radius of Na+‐insertion. Herein, a hierarchically hybrid material with hetero‐Co3S4/NiS hollow nanosphere packaged into a densified N‐doped carbon matrix (Co3S4/NiS@N‐C) was designed and fabricated utilizing CoNi‐glycerate as the self‐sacrifice template, making the utmost of the synergistic effect of hetero‐Co3S4/NiS with strong electric field and rich reaction active‐sites together with the densified outer‐carbon scaffolds with remarkable electronic conductivity and robust mechanical toughness. As anticipated, as‐fabricated Co3S4/NiS@N‐C anode affords remarkable specific capacity, prolonged cycle lifespan up to 2 400 cycles with an only 0.05% fading each cycle at 20.0 A g−1, and excellent rate feature (354.9 mAh g−1 at 30.0 A g−1), one of the best performances for most existing Co3S4/NiS‐based anodes. Ex situ structural characterizations in tandem with theoretical analysis demonstrate the reversible insertion‐conversion mechanism of initially proceeding with Na+ de‐/intercalation and superior heterogeneous interfacial reaction behavior with strong Na+‐adsorption ability. Further, sodium‐ion full cell and hybrid capacitor based on Co3S4/NiS@N‐C anode exhibit impressive electrochemical characteristics on cycling performance and rate capability, showcasing its outstanding feasibility toward practical use.

Abstract The electrocatalytic synthesis of C–N coupling compounds from CO2 and nitrogenous species not only offers an effective avenue to achieve carbon neutrality and reduce environmental pollution, but also establishes a route to synthesize valuable chemicals, such as urea, amide, and amine. This innovative approach expands the application range and product categories beyond simple carbonaceous species in electrocatalytic CO2 reduction, which is becoming a rapidly advancing field. This review summarizes the research progress in electrocatalytic urea synthesis, using N2, NO2−, and NO3− as nitrogenous species, and explores emerging trends in the electrosynthesis of amide and amine from CO2 and nitrogen species. Additionally, the future opportunities in this field are highlighted, including electrosynthesis of amino acids and other compounds containing C–N bonds, anodic C–N coupling reactions beyond water oxidation, and the catalytic mechanism of corresponding reactions. This critical review also captures the insights aimed at accelerating the development of electrochemical C–N coupling reactions, confirming the superiority of this electrochemical method over the traditional techniques.

Summary: Herein, a hierarchical NiTe@NiFe-LDH core-shell array on Ni foam (NiTe@NiFe-LDH/NF) demonstrates its effectiveness for oxygen evolution reaction (OER) in alkaline seawater electrolyte. This NiTe@NiFe-LDH/NF array showcases remarkably low overpotentials of 277 mV and 359 mV for achieving current densities of 100 and 500 mA cm−2, respectively. Also, it shows a low Tafel slope of 68.66 mV dec−1. Notably, the electrocatalyst maintains robust stability over continuous electrolysis for at least 50 h at 100 mA cm−2. The remarkable performance and hierarchical structure advantages of NiTe@NiFe-LDH/NF offer innovative insights for designing efficient seawater oxidation electrocatalysts.

Summary: High-purity hydrogen produced by water electrolysis has become a sustainable energy carrier. Due to the corrosive environments and strong oxidizing working conditions, the main challenge faced by acidic water oxidation is the decrease in the activity and stability of anodic electrocatalysts. To address this issue, efficient strategies have been developed to design electrocatalysts toward acidic OER with excellent intrinsic performance. Electronic structure modification achieved through defect engineering, doping, alloying, atomic arrangement, surface reconstruction, and constructing metal-support interactions provides an effective means to boost OER. Based on introducing OER mechanism commonly present in acidic environments, this review comprehensively summarizes the effective strategies for regulating the electronic structure to boost the activity and stability of catalytic materials. Finally, several promising research directions are discussed to inspire the design and synthesis of high-performance acidic OER electrocatalysts.

Industrial ammonia production mainly relies on the conventional Haber–Bosch process accompanied by high energy consumption and plentiful carbon dioxide emissions, which triggered the recent interest to explore more energy‐efficient and environmentally benign alternatives. Very recently, electrochemical nitrite reduction in an aqueous medium promises new opportunities for advanced, energy‐efficient, and sustainable ammonia production at ambient conditions. The ammonia formation rate and Faradic efficiency are strongly associated with the adopted electrocatalysts; therefore, striving for high‐efficient electrocatalysts is the key to sustainable ammonia production via the electrochemical nitrite reduction reaction. Herein, a critical overview of recent advances in electrochemical nitrite reduction reaction to ammonia is presented, highlighting the latest innovative heterogenous electrocatalysts including noble metal catalysts, transition‐metal‐based catalysts, and their compounds. Meanwhile, the possible reaction pathway of nitrite electroreduction to ammonia, ammonia detection, and catalytic activity descriptor are briefly summarized. Finally, the perspective and research challenges of electrocatalysts that convert nitrite to ammonia are outlined, increasing their contributions in the route of realizing a neutral carbon footprint.

Summary: Electrochemical reduction of nitrite (NO2−) can satisfy the necessity for NO2− contaminant removal and deliver a sustainable pathway for ammonia (NH3) generation. Its practical application yet requires highly efficient electrocatalysts to boost NH3 yield and Faradaic efficiency (FE). In this study, CoP nanoparticle-decorated TiO2 nanoribbon array on Ti plate (CoP@TiO2/TP) is verified as a high-efficiency electrocatalyst for the selective reduction of NO2− to NH3. When measured in 0.1 M NaOH with NO2−, the freestanding CoP@TiO2/TP electrode delivers a large NH3 yield of 849.57 μmol h−1 cm−2 and a high FE of 97.01% with good stability. Remarkably, the subsequently fabricated Zn–NO2− battery achieves a high power density of 1.24 mW cm−2 while delivering a NH3 yield of 714.40 μg h−1 cm−2.

Ambient electrochemical nitrite (NO2-) reduction is viewed as an effective and sustainable approach for simultaneously removing NO2- and producing ammonia (NH3). However, the complex multi-electron transfer steps involved in the NO2- reduction reaction (NO2-RR) lead to sluggish kinetics and low product selectivity toward NH3, underscoring the need for NH3 synthesis electrocatalysts with high activity and durability. Herein, we report amorphous indium–tin oxide sputtered on a TiO2 nanobelt array on a Ti plate (ITO@TiO2/TP) as a 3D NH3-producing catalyst for the NO2-. In 0.5 ​M LiClO4 with 0.1 ​M NO2-, it shows greatly boosted NO2-RR activity toward NH3 production, with excellent selectivity, achieving a large NH3 yield of 411.3 ​μmol ​h−1 ​cm−2 and a high Faradaic efficiency of 82.6%. It also shows high durability for continuous electrolysis. A Zn‐NO2- battery with ITO@TiO2/TP cathode offers an NH3 yield of 23.1 ​μmol ​h−1 ​cm−2 and a peak power density of 1.22 ​mW ​cm−2.

Abstract Electrochemical nitrate (NO3−) reduction is a green and economic route for ammonia (NH3) synthesis. However, this conversion suffers from low NH3 selectivity due to strong competition from other NO3− reduction pathways. Here, we report that a plasma‐induced defective CoTiO3 − x nanofiber with oxygen vacancies acts as an efficient electrocatalyst for NO3− reduction to NH3. In 0.1 M NaOH solution containing 0.1 M NO3−, it is capable of achieving a remarkable NH3 yield of 30.4 mg h–1 mgcat.–1 and a high Faradaic efficiency of 92.6%. The catalyst also shows strong electrochemical stability for a 20‐h electrolysis test. Additionally, a Zn‐NO3− battery using CoTiO3 − x as the cathode catalyst offers a peak power density of 5.04 mW cm−2 and a large NH3 yield of 3.08 mg h−1 mgcat.−1. The catalytic mechanism is further discussed by density functional theory calculations.

Seawater electrolysis is an extremely attractive approach for harvesting clean hydrogen energy, but detrimental chlorine species (i.e., chloride and hypochlorite) cause severe corrosion at the anode. Here, we report our recent finding that benzoate anions-intercalated NiFe-layered double hydroxide nanosheet on carbon cloth (BZ-NiFe-LDH/CC) behaves as a highly efficient and durable monolithic catalyst for alkaline seawater oxidation, affords enlarged interlayer spacing of LDH, inhibits chlorine (electro)chemistry, and alleviates local pH drop of the electrode. It only needs an overpotential of 320 mV to reach a current density of 500 mA·cm–2 in 1 M KOH. In contrast to the fast activity decay of NiFe-LDH/CC counterpart during long-term electrolysis, BZ-NiFe-LDH/CC achieves stable 100-h electrolysis at an industrial-level current density of 500 mA·cm–2 in alkaline seawater. Operando Raman spectroscopy studies further identify structural changes of disordered δ (NiIII-O) during the seawater oxidation process.

To restore the natural nitrogen cycle (N-cycle), artificial N-cycle electrocatalysis with flexibility, sustainability, and compatibility can convert intermittent renewable energy (e.g., wind) to harmful or value-added chemicals with minimal carbon emissions. The background of such N-cycles, such as nitrogen fixation, ammonia oxidation, and nitrate reduction, is briefly introduced here. The discussion of emerging nanostructures in various conversion reactions is focused on the architecture/compositional design, electrochemical performances, reaction mechanisms, and instructive tests. Energy device advancements for achieving more functions as well as in situ/operando characterizations toward understanding key steps are also highlighted. Furthermore, some recently proposed reactions as well as less discussed C–N coupling reactions are also summarized. We classify inorganic nitrogen sources that convert to each other under an applied voltage into three types, namely, abundant nitrogen, toxic nitrate (nitrite), and nitrogen oxides, and useful compounds such as ammonia, hydrazine, and hydroxylamine, with the goal of providing more critical insights into strategies to facilitate the development of our circular nitrogen economy.

Seawater electrolysis has great potential to generate clean hydrogen energy, but it is a formidable challenge. In this study, we report CoFe-LDH nanosheet uniformly decorated on a CuO nanowire array on Cu foam (CuO@CoFe-LDH/CF) for seawater oxidation. Such CuO@CoFe-LDH/CF exhibits high oxygen evolution reaction electrocatalytic activity, demanding only an overpotential of 336 mV to generate a current density of 100 mA cm−2 in alkaline seawater. Moreover, it can operate continuously for at least 50 h without obvious activity attenuation.

Electrochemical carbon monoxide reduction is a promising strategy to yield valuable multicarbon products but low selectivities and Faradaic efficiencies are common. Here the authors show single atom copper catalyst supported on MXene with high CO reduction performance and stability.

The development of efficient electrochemical seawater splitting catalysts for large-scale hydrogen production is of great importance. In this work, we report an amorphous Co-Mo-B film on Ni foam (Co-Mo-B/NF) via a facile one-step electrodeposition process. Such amorphous Co-Mo-B/NF possesses superior activity with a small overpotential of 199 mV at 100 mA cm−2 for a hydrogen evolution reaction in alkaline seawater. Notably, Co-Mo-B/NF also maintains excellent stability for at least 24 h under alkaline seawater electrolysis.

NH3 plays an indispensable role in agriculture, fertilizer production as well as in the chemical industry. However, its large‐scale production still relies deeply on the century‐old Haber–Bosch process under high temperature and pressure along with greenhouse gas emission and fossil fuel consumption. The electrocatalytic and photocatalytic N2 reduction reactions (NRRs) for NH3 production are favorable approaches to avoid these issues because they are carbon‐neutral and energy‐saving. Recently, the nonprecious metal oxides (NPMO) have gathered the most attention due to their ease of synthesis, controllable stability, lower cost, and environmental friendliness. Herein, the recent advances in NPMO electrocatalysts and photocatalysts for the NRR are narrated and the strategies to improve the poor NRR activity of pristine NPMOs by heteroatom doping to engineer their surface‐active sites and introduction of oxygen vacancies are highlighted. A brief summary of and the future perspective on this research field are also presented.

Organic pollutants in domestic sewage, agricultural runoff, industrial wastewater, and contaminated land pose a serious threat to human beings as well as to ecosystems. Anodic oxidation is one of the technologies most commonly used for the degradation of organic pollutants. In this review, we present the current status of promising anodic oxidation technologies for the degradation of organic pollutants, with fundamental insights into anode materials, operating conditions and mechanisms. Firstly, anodes based on metallic Pt, metal oxides (RuO2, IrO2, PbO2 and SnO2), and carbon (BDD and others) are critically reviewed. Secondly, strategies for the effective removal of organic pollutants in wastewater under appropriate operating conditions are systematically investigated. Thirdly, the anodic oxidation mechanism is comprehensively summarized with illustrations of how the organic pollutants can be broken down into small molecules of low or zero toxicity. Finally, we conclude with some future perspectives for application of anodic oxidation.

Metal organic frameworks (MOFs) show excellent electrochemical performances due to their ultrahigh porosity, large specific surface area, and easy functionalization. These characteristics make it fascinating electrode materials with excellent electrochemical performance for the currently dominated lithium-based batteries (e.g., Li-ion batteries, Li-S batteries, Li-O2 batteries). Hence, this review summarizes the recent advances of MOFs-based materials as an electrode for high-performance lithium-ion storage. Firstly, we briefly describe the development history, principle, and mechanism of the lithium-based batteries. Then, the recent advances of MOFs/MOFs composite and MOF-derived materials employed as electrode materials for Lithium-ion batteries, Li-S batteries, and Li-O2 batteries are reviewed with their electrochemical performances. Finally, we conclude and point out the future direction of MOFs-related materials for lithium-based batteries.

Abstract Renewable‐electricity‐driven N2 reduction is an attractive approach for ambient NH3 synthesis, but active electrocatalysts are needed to enable the N2 reduction reaction. Monolithic electrodes with active components anchored on conductive supports provide many advantages like structural stability, large surface area, and low electrical resistance. Here, a novel “oxidation‐etching” strategy is proposed to carve the surface of Cu foam into structures of particles, cubes, and sheets for N2 reduction electrocatalysis. The optimal catalyst achieves a Faradic efficiency as high as 18% at −0.35 V vs reversible hydrogen electrode (RHE) and a large NH3 yield of 2.45 × 10−10 mol s−1 cm−1 at −0.40 V vs RHE in 0.1 M HCl. Notably, it also shows superior long‐term electrochemical durability, with the preservation of electro‐activity for at least 20 hours.

Electrochemical reduction of nitrogen is a promising route to industrial-scale nitrogen fixation at ambient conditions, but is challenged by activation of inert nitrogen. Here the authors report a metal-free catalyst that selectively reduces nitrogen to ammonia with high efficiency and stability.

In this paper, we report on the large-scale, rapid synthesis of uniform rectangular coordination polymer nanoplates (RCPNs) assembled from Cu(II) and 4,4'-bipyridine for the first time. We further demonstrate that such RCPNs can be used as a very effective fluorescent sensing platform for multiple DNA detection with a detection limit as low as 30 pM and a high selectivity down to single-base mismatch. The DNA detection is accomplished by the following two steps: (1) RCPN binds dye-labeled single-stranded DNA (ssDNA) probe, which brings dye and RCPN into close proximity, leading to fluorescence quenching; (2) Specific hybridization of the probe with its target generates a double-stranded DNA (dsDNA) which detaches from RCPN, leading to fluorescence recovery. It suggests that this sensing system can well discriminate complementary and mismatched DNA sequences. The exact mechanism of fluorescence quenching involved is elucidated experimentally and its use in a human blood serum system is also demonstrated successfully.

In this paper, we report on the large-scale formation of supramolecular rhombus microparticles (SRMs) driven by electrostatic assembly, carried out by direct mixing of an aqueous HAuCl(4) solution and an ethanol solution of 4,4'-bipyridine at room temperature. We further demonstrate their use as an effective fluorescent sensing platform for nucleic acid detection with a high selectivity down to single-base mismatch. The general concept used in this approach is based on adsorption of the fluorescently labeled single-stranded DNA (ssDNA) probe by SRM, which is accompanied by substantial fluorescence quenching. In the following assay, specific hybridization with its target to form double-stranded DNA (dsDNA) results in desorption of ssDNA from SRM surface and subsequent fluorescence recovery.

In this paper, we demonstrate for the first time that poly(m-phenylenediamine) (PMPD) nanospheres and nanorods can be selectively synthesized via chemical oxidation polymerization of m-phenylenediamine (MPD) monomers using ammonium persulfate (APS) as an oxidant at room temperature. It suggests that the pH value plays a critical role in controlling the the morphology of the nanostructures and fast polymerization rate favors the anisotropic growth of PMPD under homogeneous nucleation condition. We further demonstrate that such PMPD nanostructures can be used as an effective fluorescent sensing platform for multiplex nucleic acid detection. A detection limit as low as 50 pM and a high selectivity down to single-base mismatch could be achieved. The fluorescence quenching is attributed to photoinduced electron transfer from nitrogen atom in PMPD to excited fluorophore. Most importantly, the successful use of this sensing platform in human blood serum system is also demonstrated.