The electrochemical synthesis of hydrogen peroxide represents a promising alternative to the traditional anthraquinone process, aiming for zero pollution. However, achieving efficient electrochemical synthesis of hydrogen peroxide in neutral electrolytes is challenging due to the sluggish kinetics of the two-electron oxygen reduction reaction. To address this issue, a unique metal-organic framework (MOF) featuring Cr metal sites coordinated with tetrabromoterephthalic acid (Cr-TBA) is synthesized. This specially designed MOF exhibits a distinctive paper-clip-like structure and remarkably enhanced Lewis acidity. Experimental results demonstrate that the obtained structure can facilitate the attraction of OH- ions in solution, promoting their accumulation on the catalyst surface. This enhancement leads to excellent performances of Cr-TBA in neutral electrolytes, achieving Faradaic efficiencies of 96-98% and a production rate of 13.4 mol gcat -1 h-1 at the current density of 150 mA cm-2. Operando spectroscopy and density functional theory calculations indicate that this modified microenvironment effectively facilitates the conversion of the *OOH intermediates to H2O2 on the catalyst surface.

Nickel-based perovskite oxides are identified as promising candidates for oxygen evolution reaction (OER) catalysts in view of their low cost, highly tunable structure, and potential high activity. However, the performance and catalyst design are hindered by their sluggish surface reconstruction kinetics. We introduce a ferric ion pre-etching strategy to enhance the surface reconstruction of typical LaNiO3. The hydrolysis of ferric ions generates hydrated protons that corrode the La-O terminal sites, inducing lattice distortion and lowering the energy barrier for reconstruction. Concurrently, ferric ion substitution for Ni creates crucial active sites after OER reconstruction, and enables the low-activity LaNiO3 to become highly active and superior to the benchmark RuO2 and NiFe layered double hydroxides (LDHs). In situ X-ray absorption spectroscopy (XAS) and in situ Raman spectroscopy reveal substantial surface transformation from corner-sharing to edge-sharing NiO6 at 1.43 V versus reversible hydrogen electrode (RHE) in the surface pre-etched sample (LNFeIII-spe). This reconstruction is initiated by the lattice oxygen mechanism (LOM) and transitions to the adsorbate evolution mechanism (AEM), underscoring the transformation of distinct OER mechanisms.

Aqueous zinc–iodine (Zn–I 2 ) batteries have emerged as a promising candidate for large-scale energy storage applications, owing to their inherent safety, cost-effectiveness, and high specific capacity. However, their commercial implementation is severely hindered by the irreversible capacity degradation and limited cycle life, which are caused by the unavoidable iodine shuttle effect resulting from the formation of soluble I 3 − species. Herein, we report the synthesis of three-dimensional hexapod-like fluorine-containing zeolitic imidazolate framework (H-F-ZIF) nanoparticles for separator modification to effectively inhibit the iodine shuttle effect. The modified layer can interact with the I 3 − species at the cathode–separator interface where the iodine shuttle occurs. Furthermore, the fluorine-containing functional group (─CF 3 ) serves as an electron acceptor, enhancing the electrostatic interaction with I 3 − species, and thereby improving the polyiodide capture capacity. As a result, the Zn–I 2 battery using H-F-ZIF modified separator exhibits excellent cycling durability and high capacity, retaining a capacity of 155.7 mAh g −1 after 12 000 cycles at 1.2 A g −1 , and a coulombic efficiency of 86.4% after 48 h of resting.

Non-noble metal-based heteroatom compounds demonstrate excellent electrocatalytic activity for the oxygen evolution reaction (OER). However, the origin of this activity, driven by structure evolution effects, remains unclear due to the lack of effective in situ/operando techniques. Herein, we employ the operando quick-scan x-ray absorption fine structure (Q-XAFS) technique coupled with in situ controlled electrochemical potential to establish a structure-activity correlation of the OER catalyst. Using Ni-Fe bimetallic phosphides as a model catalyst, operando Q-XAFS experiments reveal that the structural transformation initiates at the preferential oxidation of Fe sites over Ni sites. The in situ-generated O-Fe-P structure serves as the origin of the enhanced electrocatalytic OER activity of the catalyst, a finding supported by theoretical calculations. This work provides crucial insights into understanding the reaction mechanism of the state-of-the-art Ni-Fe-based OER electrocatalysts, thus advancing the rational design of more efficient OER electrocatalysts.

The electrocatalytic conversion of nitric oxide (NO) to ammonia (NH 3 ) epitomizes an advanced approach in NH 3 synthesis, crucial for efficiently converting low‐concentration industrial NO exhaust and contributing significantly to environmental preservation. Catalyst design remains one pivotal element in addressing this challenge. Here, efficient Cu─Co dual active sites embedded in hollow cobalt oxide nanoboxes are created for the electrocatalytic low‐concentration NO reduction reaction (NORR). Cu‐modified cobalt oxide (Cu‐Co 3 O 4 ) and its heterophase interface with copper oxide (Cu‐Co 3 O 4 /CuO) both exhibit over 93% Faraday efficiency for NH 3 synthesis, with a yield reaching up to 59.10 µg h −1 mg cat −1 at −0.4 V versus reversible hydrogen electrode by utilizing simulated industrial NO exhaust (1 vol %) as the feedstock, surpassing those of pure cobalt oxide and some reported catalysts. Theoretical calculations and NO temperature‐programmed desorption experiments demonstrate that the incorporation of Cu significantly enhances NO adsorption and reduces the energy barrier of the rate‐determining step. The integration of Cu‐Co 3 O 4 and Cu‐Co 3 O 4 /CuO within the cathode of the Zn–NO battery demonstrates a notable power density of 2.02 mW cm −2 , highlighting a propitious direction for investigating highly efficient conversion of low‐concentration NO exhaust gas.

The practical application of metalloid black phosphorus (BP) based anodes for potassium ion batteries is mainly impeded by its instability in air and irreversible/sluggish potassium storage behaviors. Herein, a 2D composite is purposefully conceptualized, where ultrathin BP nanodisks with Fe3O4 nanoclusters are hybridized with Lewis acid iron (V)-oxo complex (FC) nanosheets (denoted as BP@Fe3O4-NCs@FC). The introduced electron coordinate bridge between FC and BP, and hydrophobic surface of FC synergistically assure that BP@Fe3O4-NCs@FC is ultrastable in humid air. With the purposeful structural and componential design, the resultant BP@Fe3O4-NCs@FC anode is endowed with appealing electrochemical performance in terms of reversible capacity, rate behavior, and long-duration cycling stability in both half and full cells. Furthermore, the underlying formation and potassium-storage mechanisms of BP@Fe3O4-NCs@FC are tentatively proposed. The in-depth insights here will provide a crucial understanding in rational exploration of advanced anodes for next-generation PIBs.

Rational design of the coordination environment of single-atom catalysts (SACs) can enhance their catalytic activity, which is of great significance for high-loading and lean-electrolyte lithium-sulfur (Li─S) batteries. Inspired by the Lewis acid–base theory, we design a unique coordination environment for constructing electron-deficient Co SACs on carbon nanotubes (named as CNT@f-CoNC), which function as a Lewis acid, to enhance the chemisorption and catalytic activity towards polysulfides (Lewis base). Compared with porphyrin-like Co SACs, electron-deficient Co SACs (Lewis acid) exhibit much stronger binding affinity towards polysulfides (Lewis base) and a significantly lower energy barrier of the rate-determining step in the sulfur reduction reaction. As expected, even with a high sulfur loading (6.9 mg cm −2 ) and lean electrolyte to sulfur (E/S) ratio (4.0 µL mg −1 ), the areal capacity still reaches 7.7 mAh cm −2 . Moreover, a 1.6 Ah-class pouch cell is successfully assembled under the harsh conditions and delivers an energy density of 422 Wh kg −1 . This work provides novel insights into enhancing the electrochemical performance of Li─S batteries by modulating the local electronic density of metal sites through the rational design of the coordination environment.

Photocatalytic O2 reduction is an intriguing approach to producing H2O2, but its efficiency is often hindered by the limited solubility and mass transfer of O2 in the aqueous phase. Here, we design and fabricate a two-layered (2L) Janus fiber membrane photocatalyst with asymmetric hydrophobicity for efficient photocatalytic H2O2 production. The top layer of the membrane consists of superhydrophobic polytetrafluoroethylene (PTFE) fibers with a dispersed modified carbon nitride (mCN) photocatalyst. Amphiphilic Nafion (Naf) ionomer is sprayed onto this layer to modulate the microenvironment and achieve moderate hydrophobicity. In contrast, the bottom layer consists of bare PTFE fibers with high hydrophobicity. The elaborate structural configuration and asymmetric hydrophobicity feature of the optimized membrane photocatalyst (designated as 2L-mCN/F-Naf; F, PTFE) allow most mCN to be exposed with gas-liquid-solid triple-phase interfaces and enable rapid mass transfer of gaseous O2 within the hierarchical membrane, thus increasing the local O2 concentration near the mCN photocatalyst. As a result, the optimized 2L-mCN/F-Naf membrane photocatalyst shows remarkable photocatalytic H2O2 production activity, achieving a rate of 5.38 mmol g-1 h-1 under visible light irradiation.

The controllable photocatalytic C−C coupling of methanol to produce ethylene glycol (EG) is a highly desirable but challenging objective for replacing the current energy-intensive thermocatalytic process. Here, we develop a metal-free porous boron nitride catalyst that demonstrates exceptional selectivity in the photocatalytic production of EG from methanol under mild conditions. Comprehensive experiments and calculations are conducted to thoroughly investigate the reaction mechanism, revealing that the OB 3 unit in the porous BN plays a critical role in the preferential activation of C−H bond in methanol to form ⋅CH 2 OH via a concerted proton-electron transfer mechanism. More prominent energy barriers are observed for the further dehydrogenation of the ⋅CH 2 OH intermediate on the OB 3 unit, inhibiting the formation of some other by-products during the catalytic process. Additionally, a small downhill energy barrier for the coupling of ⋅CH 2 OH in the OB 3 unit promotes the selective generation of EG. This study provides valuable insights into the underlying mechanisms and can serve as a guide for the design and optimization of photocatalysts for efficient and selective EG production under mild conditions.

The use of MnO2 as a promising cathode material for aqueous zinc ion batteries (AZIBs) remains challenging, because its inherent poor electrical conductivity and huge volume changes lead to a fast capacity decay, short cycle life, and sluggish electrode kinetics. In this study, ultrathin MnO2 nanoflakes grown on N-doped hollow carbon spheres (defined as MnO2-NHCSs) were prepared via a simple solution-phase route and subsequent hydrothermal process, and then evaluated for their potential as a cathode for AZIBs. Ultrathin MnO2 nanoflakes decorated on NHCSs endow the overall electrode with abundant exposed active sites and excellent electrical conductivity, which could buffer the volumetric expansion and facilitate the charge-transfer kinetics. Owing to these favorable structural characteristics, the as-synthesized MnO2-NHCS composite can display a high discharge capacity of 349 mA h g(-1) at 0.1 A g(-1) after 80 cycles. Significantly, ultra-stable long-term cycling performance of 100 mA h g(-1) with a superior capacity retention of 78.7% is achieved after 2000 cycles at 2.0 A g(-1). Such notable electrochemical properties of MnO2-NHCSs are demonstrated to be superior to that of pure MnO2 hollow spheres (MnO2-HSs) and other previously reported manganese-based oxide cathodes, which is promising for practical applications.

Direct electrosynthesis of hydrogen peroxide (H2O2) with high production rate and high selectivity through the two-electron oxygen reduction reaction (2e(-)ORR) offers a sustainable alternative to the energy-intensive anthraquinone technology but remains a challenge. Herein, a low-coordinated, 2D conductive Zn/Cu metal-organic framework supported on hollow nanocube structures (ZnCu-MOF (H)) is rationally designed and synthesized. The as-prepared ZnCu-MOF (H) catalyst exhibits substantially boosted electrocatalytic kinetics, enhanced H2O2 selectivity, and ultra-high Faradaic efficiency for 2e(-)ORR process in both alkaline and neutral conditions. Electrochemical measurements, operando/quasi in situ spectroscopy, and theoretical calculation demonstrate that the introduction of Cu atoms with low-coordinated structures induces the transformation of active sites, resulting in the beneficial electron transfer and the optimized energy barrier, thereby improving the electrocatalytic activity and selectivity.

Deep-sea equipment usually operates under dwell-fatigue condition, which means the equipped energy storage devices must survive under the changing pressure. Special mechanical designs should be considered to maintain the electrochemical performance of electrodes under this extreme condition. In this work, an effective assembly strategy is proposed to accommodate the dwell-fatigue loading using Ag decorated reduced graphene oxide (rGO) foam (denoted as AGF) as a superelastic and robust Zn host. The wet-press assembly process enables the formation of highly porous and robust framework. The strong synergetic effect between rGO and Ag further guarantees AGF's superelasticity and ultrahigh mechanical strength. Meanwhile, the homogeneously distributed Ag species on the rGO sheets act as zincophilic sites to effectively facilitate Zn plating. Furthermore, AGF offers enough space to address the expansion during the charge and discharge cycles. As expected, the symmetrical cell using this AGF@Zn host demonstrates a long lifespan over 400 h at a depth-of-discharge of 50%. It is worth mentioning that the superelastic AGF host realizes stable Zn plating/stripping under varying pressures.

Exploring unique single-atom sites capable of efficiently reducing O2 to H2 O2 while being inert to H2 O2 decomposition under light conditions is significant for H2 O2 photosynthesis, but it remains challenging. Herein, we report the facile design and fabrication of polymeric carbon nitride (CN) decorated with single-Zn sites that have tailorable local coordination environments, which is enabled by utilizing different Zn salt anions. Specifically, the O atom from acetate (OAc) anion participates in the coordination of single-Zn sites on CN, forming asymmetric Zn-N3 O moiety on CN (denoted as CN/Zn-OAc), in contrast to the obtained Zn-N4 sites when sulfate (SO4 ) is adopted (CN/Zn-SO4 ). Both experimental and theoretical investigations demonstrate that the Zn-N3 O moiety exhibits higher intrinsic activity for O2 reduction to H2 O2 than the Zn-N4 moiety. This is attributed to the asymmetric N/O coordination, which promotes the adsorption of O2 and the formation of the key intermediate *OOH on Zn sites due to their modulated electronic structure. Moreover, it is inactive for H2 O2 decomposition under both dark and light conditions. As a result, the optimized CN/Zn-OAc catalyst exhibits significantly improved photocatalytic H2 O2 production activity under visible light irradiation.

The artificial disturbance in the nitrogen cycle has necessitated an urgent need for nitric oxide (NO) removal. Electrochemical technologies for NO conversion have gained increasing attention in recent years. This comprehensive review presents the recent advancements in selective electrocatalytic conversion of NO to high value-added chemicals, with specific emphasis on catalyst design, electrolyte composition, mass diffusion, and adsorption energies of key intermediate species. Furthermore, the review explores the synergistic electrochemical co-electrolysis of NO with specific carbon source molecules, enabling the synthesis of a range of valuable chemicals with C─N bonds. It also provides in-depth insights into the intricate reaction pathways and underlying mechanisms, offering valuable perspectives on the challenges and prospects of selective NO electrolysis. By advancing comprehension and fostering awareness of nitrogen cycle balance, this review contributes to the development of efficient and sustainable electrocatalytic systems for the selective synthesis of valuable chemicals from NO.

Electrocatalytic reduction of nitric oxide (NO) to ammonia (NH3) represents a potential solution for improving the disrupted nitrogen cycle balance. Unfortunately, designing efficient electrocatalysts for NO reduction reaction (NORR) remains a notable challenge, especially at low concentrations. Herein, a displacement-alloying strategy is reported to successfully induce the phase transition of Co nanoparticles supported on carbon nanosheets from face-centered cubic (fcc) to hexagonal close-packed (hcp) structure through Ru incorporation. The obtained RuCo alloy with hcp phase structure (hcp-RuCo) exhibits apparent NORR activity with a record-high Faraday efficiency of 99.2% and an NH3 yield of 77.76 µg h-1 mgcat -1 at -0.1 V versus reversible hydrogen electrode at a NO concentration of 1 vol %, surpassing Co nanoparticles with fcc phase structure and most reported catalysts. Density functional theory calculations reveal that the excellent NORR activity of hcp-RuCo can be attributed to the optimized electronic structure of Co site and lowered energy barrier of the potential rate-determining step through phase transition. Furthermore, the assembled Zn-NO battery using hcp-RuCo as the cathode achieves a power density of 2.33 mW cm-2 and an NH3 yield of 45.94 µg h-1 mgcat -1. This work provides a promising research perspective for low-concentration NO conversion.

Layered manganese dioxide is a promising cathode candidate for aqueous Zn-ion batteries. However, the narrow interlayer spacing, inferior intrinsic electronic conductivity and poor structural stability still limit its practical application. Herein, we report a two-step strategy to incorporate ammonium ions into manganese dioxide (named as AMO) nanosheets as a cathode for boosted Zn ion storage. K+ -intercalated δ-MnO2 nanosheets (KMO) grown on carbon cloth are chosen as the self-involved precursor. Of note, ammonium ions could replace K+ ions via a facile hydrothermal reaction to enlarge the lattice space and form hydrogen-bond networks. Compared with KMO, the structural stability and the ion transfer kinetics of the layered AMO are enhanced. As expected, the obtained AMO cathode exhibits remarkable electrochemical properties in terms of high reversible capacity, decent rate performance and superior cycling stability over 10000 cycles.

Gas-liquid-solid triple-phase interfaces (TPI) are essential for promoting electrochemical CO2 reduction, but it remains challenging to maximize their efficiency while integrating other desirable properties conducive to electrocatalysis. Herein, we report the elaborate design and fabrication of a superhydrophobic, conductive, and hierarchical wire membrane in which core-shell CuO nanospheres, carbon nanotubes (CNT), and polytetrafluoroethylene (PTFE) are integrated into a wire structure (designated as CuO/F/C(w); F, PTFE; C, CNT; w, wire) to maximize their respective functions. The realized architecture allows almost all CuO nanospheres to be exposed with effective TPI and good contact to conductive CNT, thus increasing the local CO2 concentration on the CuO surface and enabling fast electron/mass transfer. As a result, the CuO/F/C(w) membrane attains a Faradaic efficiency of 56.8 % and a partial current density of 68.9 mA cm(-2) for multicarbon products at -1.4 V (versus the reversible hydrogen electrode) in the H-type cell, far exceeding 10.1 % and 13.4 mA cm(-2) for bare CuO.

To alleviate the greenhouse effect and address the related energy crisis, solar-driven reduction of carbon dioxide (CO2 ) to value-added products is considered as a sustainable strategy. However, the insufficient separation and rapid recombination of photogenerated charge carriers during photocatalysis greatly limit their reduction efficiency and practical application potential. Here, isolated Cobalt (Co) atoms are successfully decorated into oxygen-doped boron nitride (BN) via an in situ pyrolysis method, achieving greatly improved catalytic activity and selectivity to the carbon monoxide (CO) product. X-ray absorption fine spectroscopy demonstrates that the isolated Co atoms are stabilized by the O and N atoms with an unsaturated CoO2 N1 configuration. Further experimental investigation and theoretical simulations confirm that the decorated Co atoms not only work as the real active center during the CO2 reduction process, but also perform as the electron pump to promote the electron/hole separation and transfer, resulting in greatly accelerated reaction kinetics and improved activity. In addition, the CoO2 N1 coordination geometry is favorable to the conversion from *CO2 to *COOH, which shall be considered as a selectivity-determining step for the evolution of the CO products. The surface modulation strategy at the atomic level opens a new avenue for regulating the reaction kinetics for photocatalytic CO2 reduction.

The lithium (Li) metal anode (LMA) is susceptible to failure due to the growth of Li dendrites caused by an un-satisfied solid electrolyte interface (SEI). With this regard, the design of artificial SEIs with improved physico-chemical and mechanical properties has been demonstrated to be important to stabilize the LMAs. This review comprehensively summarizes current efficient strategies and key progresses in surface engineering for constructing protective layers to serve as the artificial SEIs, including pretreating the LMAs with the reagents situated in different primary states of matter (solid, liquid, and gas) or using some peculiar pathways (plasma, for example). The fundamental characterization tools for studying the protective layers on the LMAs are also briefly introduced. Last, strategic guidance for the deliberate design of surface engineering is provided, and the current challenges, opportunities, and possible future directions of these strategies for the development of LMAs in practical applications are discussed.

Correction for ‘Shape-controlled synthesis of porous Co3O4 nanostructures for application in supercapacitors’ by Ting Zhu et al., J. Mater. Chem., 2010, 20, 7015–7020, https://doi.org/10.1039/C0JM00867B.