Coupling Strategy Research Articles

Oriented immobilization of nanobodies using SpyCatcher/SpyTag significantly enhances the capacity of affinity chromatography

The use of nanobodies (Nbs) in affinity chromatography for biomacromolecule purification is gaining popularity. However, high-performance Nb-based affinity resins are not readily available, mainly due to the lack of suitable immobilization methods. In this study, we explored an autocatalytic coupling strategy based on the SpyCatcher/SpyTag chemistry to achieve oriented immobilization of Nb ligands. To facilitate this approach, a variant cSpyCatcher003 (cSC003) was coupled onto agarose microspheres, providing a specific attachment site for SpyTagged nanobody ligands. The cSC003 easily purified from Escherichia coli through a two-step procedure, exhibits exceptional alkali resistance and structural recovery capability, highlighting its robustness as a linker in the coupling strategy. To validate the effectiveness of cSC003-derivatized support, we employed VHSA, a nanobody against human serum albumin (HSA), as the model ligand. Notably, the immobilization of SpyTagged VHSA onto the cSC003-derivatized support was achieved with a coupling efficiency of 90 %, significantly higher than that of traditional thiol-based coupling method. This improvement directly correlated to the preservation of the native conformation of nanobodies during the coupling process. In addition, the Spy-immobilized resin demonstrated better performance in the binding capacity, with a 3-fold improvement in capture efficiency, underscoring the advantages of the Spy immobilization strategy for oriented immobilization of VHSA ligands. Moreover, online purification and immobilization of SpyTagged VHSA from crude bacterial lysate was achieved using the cSC003-derivatized support. The resulting resin exhibited high binding specificity towards HSA, yielding a purity above 95 % directly from human serum, and maintained good stability throughout multiple purification cycles. These findings highlight the potential of the Spy immobilization strategy for developing Nb-based affinity chromatographic materials, with significant implications for biopharmaceutical downstream processes.

Anderson acceleration for PWR whole-core pin-by-pin Nu-TH coupling calculation in NECP-Bamboo2.0

For PWR whole-core pin-by-pin neutronics/thermal-hydraulics (Nu-TH) coupling analysis, the Picard iteration strategy is widely employed benefitting from the convenience of implementation. Nevertheless, it is limited to the global multi-physics convergence rate regarding its oscillatory convergence behaviors in the local solution of each single-physics field. In this paper, the Anderson Acceleration (AA) scheme is employed and investigated to enhance the convergence performance of the pin-by-pin Nu and subchannel TH coupling analysis code NECP-Bamboo2.0. Different from the classical relaxation scheme where the relaxation factor is predetermined and fixed, the AA scheme utilizes the linear combination of several previous solutions to correct the current solution. The coefficients of this linear combination can be obtained by solving the residual equation, making the approach more robust. In addition, the selection of the accelerated solution vector is investigated based on the tightly coupling strategy of Nu-TH in NECP-Bamboo2.0. It is illustrated that the neutron-transport solution vector could have superior theoretical acceleration performance compared to the commonly used TH solution vector in the practical PWR analysis scenario. Finally, the AA scheme in NECP-Bamboo2.0 is validated using the VERA#6 3D single-assembly transport/TH coupling benchmark problem and the VERA#7 3D whole-core multi-physics coupling benchmark. It is demonstrated by the numerical results that the AA scheme possesses good robustness and computational efficiency. For the 3D whole-core VERA#7 benchmark, compared with the classic Picard iteration with a relaxation factor of 0.5, the AA scheme based on the neutron-transport solution vector can reduce the number of global iterations and calculation time by around 80%.

An OpenFOAM solver for multiphysics modeling of fusion reactor design: The nemoFoam code

This paper introduces a multiphysics code, named nemoFoam, designed within the OpenFOAM environment to address the coupling of neutron and photon transport with thermal-hydraulics in nuclear reactor simulations. The code, conceived both for fusion and fission applications, employs a modular approach where the neutronic module is currently based on multi-group neutron diffusion equations, including a mono-kinetic treatment for photons. The thermal-hydraulic module is built on the standard OpenFOAM solver. The paper focuses on presenting the key features of nemoFoam and discussing the structure of the code, the nuclear and thermal-hydraulic models, and the coupling strategy between them.In order to assess the performance of the neutronic module, the code is applied to a fusion case study, indeed a benchmark against the Serpent Monte Carlo code for neutron and photon transport is performed, applying nemoFoam to the Affordable, Robust and Compact (ARC) fusion reactor design. Simulation results demonstrate good agreement with Monte Carlo benchmarks, emphasizing the potential of the code for multiphysics simulations. The modular design of nemoFoam allows users to extend the implemented model equations to study additional phenomena, focus only on selected aspects independently and, potentially, to add new solvers in each module.

Ternary Rotational Polyanion Coupling Enables Fast Li Ion Dynamics in Tetrafluoroborate Ion Doped Antiperovskite Li2OHCl Solid Electrolyte

AbstractLi‐rich antiperovskite (LiRAP) hydroxyhalides are emerging as attractive solid electrolyte (SEs) for all‐solid‐state Li metal batteries (ASSLMBs) due to their low melting point, low cost, and ease of scaling‐up. The incorporation of rotational polyanions can reduce the activation energy and thus improve the Li ion conductivity of SEs. Herein, we propose a ternary rotational polyanion coupling strategy to fasten the Li ion conduction in tetrafluoroborate (BF4−) ion doped LiRAP Li2OHCl. Assisted by first‐principles calculation, powder X‐ray diffraction, solid‐state magnetic resonance and electrochemical impedance spectra, it is confirmed that Li ion transport in BF4− ion doped Li2OHCl is strongly associated with the rotational coupling among OH−, BF4− and Li2−O−H octahedrons, which enhances the Li ion conductivity for more than 1.8 times with the activation energy lowering 0.03 eV. This work provides a new perspective to design high‐performance superionic conductors with multi‐polyanions.

Ternary Rotational Polyanion Coupling Enables Fast Li Ion Dynamics in Tetrafluoroborate Ion Doped Antiperovskite Li2OHCl Solid Electrolyte.

Li-rich antiperovskite (LiRAP) hydroxyhalides are emerging as attractive solid electrolyte (SEs) for all-solid-state Li metal batteries (ASSLMBs) due to their low melting point, low cost, and ease of scaling-up. The incorporation of rotational polyanions can reduce the activation energy and thus improve the Li ion conductivity of SEs. Herein, we propose a ternary rotational polyanion coupling strategy to fasten the Li ion conduction in tetrafluoroborate (BF4-) ion doped LiRAP Li2OHCl. Assisted by first-principles calculation, powder X-ray diffraction, solid-state magnetic resonance and electrochemical impedance spectra, it is confirmed that Li ion transport in BF4- ion doped Li2OHCl is strongly associated with the rotational coupling among OH-, BF4- and Li2-O-H octahedrons, which enhances the Li ion conductivity for more than 1.8 times with the activation energy lowering 0.03 eV. This work provides a new perspective to design high-performance superionic conductors with multi-polyanions.

Abstract PR002: Nimbolide targets RNF114 to induce the trapping of PARP1 and synthetic lethality in BRCA-mutated cancer

Abstract Despite the tremendous success of PARP1 inhibitors (PARPi) for the treatment of BRCA mut tumors, intrinsic and acquired resistance to PARPi remains a critical challenge in the clinic. This is, at least in part, due to the incomplete understanding of the mechanism of action (MoA) of PARPi. Recent studies from both our lab and others have pointed to PARP1 trapping as a key determinant of the anticancer effects of PARP1 inhibitors (PARPi). However, the molecular underpinnings of PARP1 trapping are poorly understood. Here we performed a proteomics-based chromatin relocalization screen, and identified RNF114, as a PARylation-dependent, E3 ubiquitin ligase involved in DNA damage response. Upon sensing genotoxicity, RNF114 was recruited, in a PAR-dependent manner, to DNA lesions, where it targeted PARP1 for degradation. The blockade of this pathway interfered with the removal of PARP1 from DNA lesions, leading to profound PARP1 trapping. A unique feature of this pathway is its druggability. We showed that a natural product, nimbolide, inhibited the E3 ligase activity of RNF114 and thus caused PARP1 trapping. However, unlike conventional PARPi, nimbolide treatment induced the trapping of both PARP1 and PARylation-dependent DNA repair factors. The unique mechaism of action of nimbolide translated into its superior cytotoxicity against BRCA mut cancer cells, compared to regular PARPi. It is also able to potentially overcome intrinsic and acquired resistance to PARPi, both in vitro and in vivo. In collaboration with Dr. Tian Qin, we recently performed the first total synthesis of nimbolide via a pharmacophore-directed, late-stage coupling strategy. Using this method, we have obtained a large panel of novel nimbolide analogs with improved activity and drug-like properties. We have further garnered key SAR (structure-activity relationship) insights into nimbolide. These results point to the exciting possibility of translating nimbolide analogs into novel PARP1-targeting agents for the treatment of BRCA mut cancers. Citation Format: Peng Li, Yuanli Zhen, Chiho Kim, Zhengshuai Liu, Jianwei Hao, Heping Deng, Hejun Deng, Min Zhou, Xu-Dong Wang, Tian Qin, Yonghao Yu. Nimbolide targets RNF114 to induce the trapping of PARP1 and synthetic lethality in BRCA-mutated cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Expanding and Translating Cancer Synthetic Vulnerabilities; 2024 Jun 10-13; Montreal, Quebec, Canada. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(6 Suppl):Abstract nr PR002.

Mild and selective synthesis of imines and N-Heterocyclic compounds via formic acid-mediated reductive coupling strategy over Nitrogen-Coordinated cobalt Single-Atom catalysts

The selective formation of C = N bonds through the formic acid-mediated reductive coupling of nitro groups with carbonyl groups over heterogeneous catalysts poses challenges due to the corrosion of metal catalysts by formic acid and the rapid further hydrogenation of C = N into C-N bonds. In this study, we demonstrate that nitrogen-coordinated cobalt single-atom catalysts exhibit robust activity in this transformation. Various imines and N-heterocyclic compounds, including benzimidazoles, quinazolines, and pyrroles, can be synthesized at a modest temperature of only 70 °C. The high catalytic activity is attributed to the synergistic roles of nitrogen and cobalt atoms, serving as basic and active sites, respectively. Experimental data, complemented by density functional theory (DFT) calculations, clearly indicate that the transfer hydrogenation of nitrobenzene preferentially proceeds via the “direct” pathway rather than the “condensation” pathway. Moreover, the reduction of C = N bonds into C-N bonds demands much higher energy than the reduction of nitro groups, thereby enabling high selectivity towards C = N bonds. The findings of this study are expected to provide a novel approach for selective C = N bond formation and contribute to a deeper understanding of the mechanism underlying the reductive amination process.

Pyrolysis-free coupling strategy to synthesize two-dimensional oxygen reaction electrocatalysts for rechargeable Zn-air batteries

Although rechargeable Zn-air batteries (ZABs) representing one of the most prospective energy devices, their practical applications are primarily restricted by sluggish oxygen reduction and evolution reactions (ORR/OER). We herein propose a pyrolysis-free coupling strategy to prepare two-dimensional ORR/OER bifunctional electrocatalysts, in which atomic Fe-N4 moieties from planar iron phthalocyanine molecules for ORR and ultrathin FeCo hydroxides for OER are anchored on graphene by ultrasound-assisted coupling interactions. The obtained catalyst exhibits a small OER-ORR potential difference of 0.64 V. When used in ZABs, excellent performance is achieved such as a large power density (216 mW cm−2), a high specific capacity (743 mAh g−1), and stable charge–discharge voltage platform, demonstrating its great potential in the applications of energy devices.

Fluorescence Labeling of Peptides: Finding the Optimal Protocol for Coupling Various Dyes to ATCUN-like Structures.

Labeling of peptides and proteins with fluorescent dyes is a key step in functionalizing these structures for a wide array of biological assays. However, coupling strategies of such dyes have not been optimized for the most common compounds, while this step is typically the most precious and costly of the whole synthesis. We searched for the best conditions for attachment of the most widely used fluorescent dyes such as 6-carboxyfluorescein, Rhodamine B, and BODIPY-FL to peptides, where amino terminal Cu(II) and Ni(II) binding site (ATCUN) peptides were used as a model system. Surprisingly, conventional methods of dye attachment proved to not be satisfactory and yielded poor efficiency results. We have discovered that when labeling primary amines on peptides, the uncommon synthesis of activated pentafluorophenol (PFP) esters is the most efficient strategy, expedited by microwave irradiation. Coupling to secondary amines is achieved most efficiently through conventional coupling reagents such as HATU and PyBOP. Furthermore, we have employed our fluorescently labeled ATCUN peptides in studies for Cu(II) and Ni(II) sensing, showing that changing the fluorophore does not significantly affect the fluorescence quenching process and discovering the optimal linker length between the ATCUN core and the dye, expanding the repertoire of fluorophores that can be used in this application.

Aero-propulsion analysis of distributed ducted-fan propulsion based on lifting-line driven body-force model

As the environmental problems become increasingly serious, distributed electrical propulsion systems with higher aerodynamic efficiency and lower pollution emission have received extensive attention in recent years. The distributed electrical propulsion usually employs the new aero-propulsion integrated configuration. A simulation strategy for internal and external flow coupling based on the combination of lifting line theory and body force method is proposed. The lifting line theory and body force method as source term are embedded into the Navier-Stokes formulation. The lift and drag characteristics of the aero-propulsion coupling configuration are simulated. The results indicate that the coupling configuration has the most obvious lift augmentation at 12° angle of attack, which can provide an 11.11% increase in lift for the airfoil. At 0° angle of attack, the pressure difference on the lip parts provides the thrust component, which results in a lower drag coefficient. Additionally, the failure impact of a ducted fan at the middle or edge on aerodynamics is investigated. For the two failure conditions, the lift of the coupling configuration is decreased significantly by 27.85% and 26.14% respectively, and the lip thrust is decreased by 70.74% and 56.48% respectively.

Robustness analysis of interdependent network accounting for failure probability and coupling patterns.

The robustness of interdependent networks against perturbations is an important problem for network design and operation. This paper focuses on establishing a cascading failure dynamics model and analyzing the robustness for interdependent networks, in which the states of the nodes follow certain failure probability and various connectivity patterns. First, to describe the removal mechanism of an overloaded node, the failure probability associated with the load distribution of components was proposed. Then, we present the node capacity cost and the average capacity cost of the network to investigate the propagation of cascading failures. Finally, to discuss the impact of the configuration parameters on robustness, some numerical examples are conducted, where the robustness was analyzed based on the proposed method and different interdependence types. Our results show that, the larger the overload parameter, the more robust the network is, but this also increases the network cost. Furthermore, we find that allocating more protection resources to the nodes with higher degree can enhance the robustness of the interdependent network. The robustness of multiple-to-multiple interdependent networks outperforms that of one-to-one interdependent networks under the same coupling pattern. In addition, our results unveil that the impact of coupling strategies on the robustness of multiple-to-multiple interdependent networks is smaller than that of one-to-one interdependent networks.

Solar-Driven Biomass Reforming for Hydrogen Generation: Principles, Advances, and Challenges.

Hydrogen (H2) has emerged as a clean and versatile energy carrier to power a carbon-neutral economy for the post-fossil era. Hydrogen generation from low-cost and renewable biomass by virtually inexhaustible solar energy presents an innovative strategy to process organic solid waste, combat the energy crisis, and achieve carbon neutrality. Herein, the progress and breakthroughs in solar-powered H2 production from biomass are reviewed. The basic principles of solar-driven H2 generation from biomass are first introduced for a better understanding of the reaction mechanism. Next, the merits and shortcomings of various semiconductors and cocatalysts are summarized, and the strategies for addressing the related issues are also elaborated. Then, various bio-based feedstocks for solar-driven H2 production are reviewed with an emphasis on the effect of photocatalysts and catalytic systems on performance. Of note, the concurrent generation of value-added chemicals from biomass reforming is emphasized as well. Meanwhile, the emerging photo-thermal coupling strategy that shows a grand prospect for maximally utilizing the entire solar energy spectrum is also discussed. Further, the direct utilization of hydrogen from biomass as a green reductant for producing value-added chemicals via organic reactions is also highlighted. Finally, the challenges and perspectives of photoreforming biomass toward hydrogen are envisioned.

Internal water circulation mediated synergistic co-hydrolysis of PET/cotton textile blends in gamma-valerolactone.

Recycling strategies for mixed plastics and textile blends currently aim for recycling only one of the components. Here, we demonstrate a water coupling strategy to co-hydrolyze polyester/cotton textile blends into polymer monomers and platform chemicals in gamma-valerolactone. The blends display a proclivity for achieving an augmented 5-hydroxymethylfurfural yield relative to the degradation of cotton alone. Controlled experiments and preliminary mechanistic studies underscore that the primary driver behind this heightened conversion rate lies in the internal water circulation. The swelling and dissolving effect of gamma-valerolactone on polyester enables a fast hydrolysis of polyester at much lower concentration of acid than the one in the traditional hydrolysis methods, effectively mitigating the excessive degradation of cotton-derived product and undesirable product formation. In addition, the system is also applicable to different kinds of blends and PET mixed plastics. This strategy develops an attractive path for managing end-of-life textiles in a sustainable and efficient way.

Rapid antibody conjugation strategy via instant charge inversion of AuNBPs toward ultrasensitive SERS-LFIA detection of AFP

Alpha-fetoprotein (AFP) is widely utilized as the primary serum marker for diagnosing Hepatocellular carcinoma. Integrating surface-enhanced Raman scattering (SERS) with lateral flow immunoassays (LFIA) displays significant promise for the rapid quantification of AFP. Gold nanobipyramids (AuNBPs) is a kind of SERS probe with high activity showing strong application potential in SERS-LFIA. However, the drastic electrostatic interaction between negative charged antibodies and positive charged AuNBPs will result in uncontrollable aggregation, which poses a challenge for antibody binding and limits its application in SERS-LFIA. Hence, we propose a rapid antibody conjugation strategy with the aid of instant charge inversion of AuNBPs, which enables efficient and expedited antibody coupling onto AuNBPs. The thiol-free fish sperm (FSDNA) was employed to adsorb on the cetyltrimethylammonium bromide (CTAB) coated AuNBPs for immediate charge inversion. The adsorption of FSDNA will cause partial stripping of CTAB from the AuNBPs surface to provide additional active sites for antibodies binding. In this study, approximately average 37 AFP-antibodies were verified bonding on one charge inverted AuNBPs by direct incubation for 30 min. The antibodies modified AuNBPs were further incubated with 4-nitrothiophenol for preparing SERS immune probes, which display excellent colloid stability and specificity. The probes were used to construct SERS-LFIA strips for AFP detection, enabling highly sensitive detection of AFP with the limit of detection (LOD) as low as 0.72 pg·mL−1. The developed SERS-LFIA strip demonstrates excellent stability and accuracy in detecting serum samples, with a recovery rate ranging from 84 % to 114 %. This rapid antibody coupling strategy is applicable to a wide range of positively charged nanoparticles, effectively addressing the challenging issue of utilizing such nanomaterials in LFIA.

Coupled engineering strategy of CYB2 deletion and ACS1 overexpression improves cellulosic lactic acid production by Saccharomyces cerevisiae

Lactic acid plays a significant role in the food industry as a natural preservative and serves as a platform chemical for the production of biodegradable poly-lactic acid. While its sustainable production through fermentation using cellulosic biomass instead of traditional sugar and starch raw materials shows promise, there remains limited information available on this method. In this study, a xylose-fermenting and lactic acid-tolerant Saccharomyces cerevisiae strain (BK01) was engineered for improved cellulosic lactic acid production using the promising energy crop, kenaf. Specifically, CYB2 was deleted to inhibit lactic acid consumption (BK02), which was further engineered by ACS1 overexpression to remove the cytotoxic acetate derived from cellulosic biomass (BK03). The BK03 produced 3.25-fold more lactic acid from kenaf pulp hydrolysate than the parental strain (BK01). During pH-controlled fermentation, lactic acid production by BK03 reached a titer of 31 g/L and a productivity of 1.30 g/L-h, the highest value reported so far. This is one of the few studies on yeast-based lactic acid production from lignocellulose.

Efficient and stable coupling of the SuperdropNet deep-learning-based cloud microphysics (v0.1.0) with the ICON climate and weather model (v2.6.5)

Abstract. Machine learning (ML) algorithms can be used in Earth system models (ESMs) to emulate sub-grid-scale processes. Due to the statistical nature of ML algorithms and the high complexity of ESMs, these hybrid ML ESMs require careful validation. Simulation stability needs to be monitored in fully coupled simulations, and the plausibility of results needs to be evaluated in suitable experiments. We present the coupling of SuperdropNet, a machine learning model for emulating warm-rain processes in cloud microphysics, with ICON (Icosahedral Nonhydrostatic) model v2.6.5. SuperdropNet is trained on computationally expensive droplet-based simulations and can serve as an inexpensive proxy within weather prediction models. SuperdropNet emulates the collision–coalescence of rain and cloud droplets in a warm-rain scenario and replaces the collision–coalescence process in the two-moment cloud microphysics scheme. We address the technical challenge of integrating SuperdropNet, developed in Python and PyTorch, into ICON, written in Fortran, by implementing three different coupling strategies: embedded Python via the C foreign function interface (CFFI), pipes, and coupling of program components via Yet Another Coupler (YAC). We validate the emulator in the warm-bubble scenario and find that SuperdropNet runs stably within the experiment. By comparing experiment outcomes of the two-moment bulk scheme with SuperdropNet, we find that the results are physically consistent and discuss differences that are observed in several diagnostic variables. In addition, we provide a quantitative and qualitative computational benchmark for three different coupling strategies – embedded Python, coupler YAC, and pipes – and find that embedded Python is a useful software tool for validating hybrid ML ESMs.

Non-linear buckling analysis of thin-walled beams modeled with 7-parameter shell elements

The non-linear quasi-static buckling of thin-walled beams with arbitrary cross-sections is studied by developing coupling strategies between the composing plates (web, flanges). The element adopted for modeling the plates is a 7-parameter shell element using the Enhanced Assumed Strain concept (Büchter et al., 1994). Different nodal shell directors exist at the interface between plates for thin-walled beams with arbitrary cross-sections, requiring appropriate strategies. The coupling between plates first considers Lagrange multipliers at the interface, following the mortar method on the surface between the plates. Second a simplified pre-processing method is proposed by modifying the shell directors of the nodes close to the interface. In the case of the quasi-static buckling of thin-walled beams with L-shaped and I-shaped cross-sections, the two coupling strategies are thoroughly assessed by using three different solution procedures: Newton–Raphson, Newton–Riks and Asymptotic Numerical Method (ANM). The pre-processing method is simple and turns out to be robust and efficient.

Ethylthio-1H-tetrazole (ETT) as coupling additive for the solid-phase synthesis (SPS) of hindered amino acid-containing peptides

Peptides are finding broad applications in drug discovery as Active Pharmaceutical Ingredients (APIs) and delivery systems, and also in the field of new materials. In this context, the increasing relevance of these molecules has fueled the development of more efficient synthetic strategies at both research and industrial scales. The new generation of peptides in the market contains hindered amino acids, examples include the antidiabetic and antiobesity drugs semaglutide and tirzepatide, which contain α,α-dimethylglycine (Aib), and trofinetide, which contains α-methylproline. Given that peptide synthesis involves the proper combination of protecting groups and coupling reagents, it is important to develop coupling strategies for these hindered amino acid-containing peptides. In this first communication, we report that ethylthio-1H-tetrazole (ETT), a reagent widely used in oligonucleotide synthesis but unknown in peptide synthesis, is well suited to be used in combination with N.N’-diisopropylcarbodiimide (DIC) for the preparation of hindered amino acid-containing peptides. ETT is more acidic than 1-hydroxybenzotriazole (HOBt) and ethyl 2-hydroxyimino-2-cyanoacetate (OxymaPure), and, as such, the active species formed will have an excellent leaving group, thereby facilitating the coupling reaction. To demonstrate this concept, we synthesized analogs of Leu-enkephalin amide, where the two consecutive Gly amino acids were substituted by Aib, NMeGly, and NMeAla. The syntheses carried out with ETT were superior to those done with OxymaPure, HOBt, and 1-hydroxy-7-azabenzotriazole. (HOAt). However, in terms of racemization, ETT showed poorer performance than the other coupling additives, especially in the case of His(Trt). In conclusion, ETT emerges as an important contributor to the toolbox of coupling reagents and additives used for peptide and amide formation.

Double gradient coupling heterostructure design accurately regulates the anion process of the Li-rich cathode

Lithium-rich layered oxides are regarded as the next generation of cathode materials for lithium-ion batteries due to their high capacity and high operating voltage. However, the release of oxygen at high voltage has caused serious failure problems, severely limiting the commercial application of lithium-rich cathode materials. As the irreversible release of oxygen occurs first at the surface of the particles, the change in structure at the surface is also more drastic. In response to the variability of anion redox processes from surface to interior in the particles, a coupling strategy of Al, oxygen vacancies double gradient and spinel heterostructure was designed. The high concentration of oxygen vacancies and Al on the surface inhibits excessive oxidation of lattice oxygen and oxygen release. The surface heterostructure improves the reaction kinetics and increases the activity and reversibility of the electrode process. The concentration of oxygen vacancies and Al in the interior ensures highly active anionic redox and further enhances structural stability. The specific capacity (0.13 mAh/g/cycle) and voltage (1.34 mV/cycle) decay of the modified material is greatly reduced. In-situ and ex-situ characterisations were used to analyse the modification mechanism, which can effectively guide the improvement of lithium-rich cathode material performance.

Tailoring Ni 3d orbitals in Ni-Fe/Ni foam heterostructures for enhanced H* adsorption and boosted electrocatalytic nitrate reduction performance

The electrochemical nitrate (NO3−) reduction (ENR) in wastewater, a promising remediation strategy, is often impeded by the essential use of costly noble metals. This study introduces an innovative non-noble Ni-Fe/Ni foam cathode fabricated via one-step electrodeposition technique. Efficient nitrate removal (99.4 %) was achieved with the selectivity of 83.6 % to NH3. The exceptional performance can be ascribed to the augmented active sites and the synergistic interaction between Ni and Fe. The leftward shift of the 3d orbitals density of Ni and the elevation of density at the Fermi level on Ni foam heterostructures, consequent to Fe doping, enhance the adsorption of H*. The addition of reactive chlorine species, generated through anodizing in Cl− mediated system, further improves N2 selectivity by oxidizing intermediate NH4+ product. The coupled anodic oxidation method employed herein achieves nearly 100 % removal efficiency of total nitrogen (TN) for initial concentration of 100 mg/L within 180 min, under the conditions of 1.5 g/L Cl− concentration and a current density of 25 mA cm−2. The findings underscore the potential of the Ni-Fe/Ni foam cathode within a Cl− mediated electrocatalytic framework for nitrate wastewater treatment, providing novel insights into the design of cathode catalysts and anodic coupling strategies for efficient TN removal.