Abstract Nickel–iron‐based layered double hydroxides (NiFe LDHs) have attracted tremendous research and industrial interests for oxygen evolution reaction (OER) electrocatalysis. However, methodologies on simultaneous regulation of performance‐influencing factors remain scarce and their real synergistic effects are not clear enough. Herein, a versatile polyoxometallic acids (POMs) etching approach is reported to ingeniously reconstruct NiFe LDH, including 3D morphological nanotailoring, Fe 3+ and α‐Ni(OH) 2 active species reconfiguration, creation of multiple Ni, Fe, and O vacancies, and intercalation of POM polyanionic clusters. The experimental and theoretical data collaboratively unveil that control of the key performance‐influencing factors and their multiple synergistic mechanisms dominantly contribute to the step‐like OER performance enhancement. The reinforced electrocatalyst is further produced with low cost and high performance up to Ф180 mm in diameter, showing its feasibility and advancement of the promising configuration of NiFe LDH‐PMo12(+) II Ni@NiFe LDH(−) for alkaline anion‐exchange‐membrane electrode stack cells. Furthermore, to mathematically evaluate the evolution, a novel empirical formula is proposed for quantitative identification of structure–activity correlations, which offers an opportunity for first and fast reliability on materials screening.
Abstract Hydrogen is widely recognized as a clean energy source with vast potential to facilitate the shift toward sustainable energy systems. Seawater electrolysis presents a promising approach for large‐scale hydrogen production, capitalizing on the abundance of seawater and highlighting its significant role in future hydrogen applications. However, despite its scalability, major challenges persist—most notably, the development of high‐performance, durable electrocatalysts capable of continuous operation while resisting the corrosive effects of chloride ions in seawater. In recent years, substantial progress has been achieved in the development of efficient electrocatalysts for seawater electrolysis. This review provides an in‐depth analysis of recent developments in seawater hydrogen evolution catalysts, systematically discussing hydrogen production fundamentals, key reaction mechanisms, and persistent challenges. We compare the performance of noble metal and transition metal catalysts for seawater hydrogenation reactions and analyze their advantages and limitations. Subsequently, the focus is on exploring new ways to enhance catalytic performance through strategies such as improving catalyst conductivity, optimizing electronic effects, and enhancing catalyst synergies to facilitate efficient and stable progress in electrocatalyst design, and concludes with insights into future prospects in this field.
Abstract Crystal‐facet heterojunction engineering of mesoporous nanoreactors with highly redox‐active represents an efficacious strategy for the transformation of CO 2 into valuable C 2 products (e.g., C 2 H 4 ). Herein, hollow mesoporous cube‐like CuS nanoreactors (~860 nm) with controlled anisotropic crystal‐facets are prepared through an interfacial‐confined ion dynamic migration‐rearrangement strategy. The regulation of the S 2− ion concentration facilitates the modulation of the highly active (110) to (100) crystal‐facet ratios from 0.119 to 0.288, and induces the formation of anisotropic crystal‐facet heterojunctions. The controllable crystal‐facet heterojunctions trigger the directional charge carrier migration, and are accompanied with the formation of tandem S‐defect sites (Cu 0 ‐S 1 @S 3 ). Both of them promote the efficient electron‐hole pair dissociation and attain asymmetric C−C coupling. The hollow mesoporous CuS nanoreactors with optimized crystal‐facet ratio of 0.224 (HMe‐CuS‐3) deliver a high selectivity of 72.7 % for the photocatalytic reduction of CO 2 to acetylene (C 2 H 2 ). Further constructed Au‐(110) and Co 3 O 4 ‐(100) spatially separated cascade nanoreactors (SS‐Au@Co 3 O 4 ‐CuS) achieve CO 2 ‐C 2 H 4 photoreduction, in which the Co‐sites enhance H 2 O dissociation to provide protons and the protonation of *CO to *COH. The *COH is further captured by Au‐sites to accomplish the asymmetric *CO‐*COH coupling and subsequent protonation, ensuring a high C 2 H 4 generation rate of 4.11 μmol/g/h with a selectivity as high as 90.6 %.
Read moreComposite reinforced mortar (CRM) systems represent a strengthening solution for existing masonry structures consisting of a composite mesh embedded within a layer of structural mortar. Diagonal compression tests on natural stone masonry panels (URM) are reported, aimed at assessing the effectiveness of a hybrid CRM-FRCM system. The tested system was comprised of a 25 mm natural hydraulic lime-based mortar and a 20 × 20 mm AR glass grid applied on only one side of the panels in order to simulate the most commonly encountered strengthening configuration. The results showed an average increase in shear resistance of 32% compared to the average properties of the URM walls, while preserving the average shear stiffness. In addition, previously tested natural stone URM panels were repaired using the same strengthening solutions and were retested in diagonal compression. For the retested specimens the original shear capacity was recovered up to 98%, demonstrating the effectiveness of the strengthening system as a remediation solution for damaged masonry.
Read moreDue to complexities from the interaction between steel tube and concrete filling of concrete-filled steel tubular (CFST) columns, their strengths are very complicated, which is a highly nonlinear relation with material strengths and geometry. Categorical gradient Boosting (CatBoost), which is advanced boosting machine, is presented to solve the problems. A total of 3103 tests, which is divided in four datasets, is trained and tested the learners to determine the ultimate axial strength as the output variable while the strength of materials (concrete and steel) and geometry (e.g., diameters/width/heights, thickness, effective length, eccentricities) are the input ones. The comparison of the present results from 10-fold cross validation and those from the code predictions (AISC 360-16, Eurocode 4 and AS/NZS 2327) and previous study shows very high prediction accuracy in terms of coefficient of determination (R2), which is the lowest value (R2 = 0.964) for Dataset 2 and the highest one (R2 = 0.996) for Dataset 1. While the predictions from three codes beyond material limit and slenderness are less conservative than those within it, CatBoost provides nearly similar experiment results with the mean values as unity without any limits. This algorithm can be used to predict an accurate strength of CFST columns.
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Read moreCatalytic reactions play a key role in energy production, green chemistry and chemical synthesis, and are the cornerstone for addressing global challenges such as environmental pollution and energy crisis. The design and performance optimization of efficient catalysts rely on a deep understanding of their structural characteristics, electronic states and kinetic behaviors during reactions, and advanced characterization techniques provide key technical support. This review summarizes the applications, advantages and limitations of spectroscopic techniques (X-ray absorption spectroscopy, Nuclear magnetic resonance, Raman spectroscopy, Infrared spectroscopy and Electron paramagnetic resonance), Microscopic imaging techniques (Transmission electron microscopy, Scanning electron microscopy and Atomic force microscopy) and component analysis techniques (X-ray photoelectron spectroscopy, X-ray diffraction and Inductively coupled plasma mass spectrometry) in catalytic research. These techniques can provide multi-dimensional insights into the microstructure of catalysts, the properties of active sites and their evolution during reactions, laying a solid foundation for elucidating catalytic mechanisms and optimizing catalyst performance. Although current characterization methods still face challenges in spatial resolution, compatibility with extreme reaction conditions and data processing complexity, significant progress is expected through emerging strategies such as multi-technique integration and artificial intelligence-assisted analysis. This review aims to provide a reference for researchers in the field of catalysis and a forward-looking perspective for the development of characterization techniques.
Read moreAbstract The limited design strategy of three‐dimensional covalent organic frameworks (3D COFs) greatly restricts their structural diversification and potential applications. Herein, we propose an inwardly directed linker propagation strategy for the targeted assembly of 3D COFs (COF‐IN‐1 and COF‐IN‐2) and compare them with outwardly directed expanded COFs (COF‐OUT‐1 and COF‐OUT‐2). COF‐OUTs exhibit planar heteroporous 2D frameworks with cpt topology, while COF‐INs engineer controlled triple entanglements into networks, forming 3D frameworks with acs topology. Moreover, the COFs assembled via inwardly directed linker propagation effectively enhanced the production of H 2 O 2 photosynthesis. To demonstrate the application potential, a biphasic fluid system was constructed for continuous H 2 O 2 photosynthesis and extraction. This work not only expands the design strategy for achieving 3D COFs but also demonstrates that the dimensional regulation of frameworks and tuning of applications can arise from different expanding directions of the linkers.
Read moreAbstract Synthetic high-performance fibers, such as polyaramid fibers, have attracted particular attention owing to their excellent mechanical properties and promising applications in safety protection fields. However, fabricating fibers with high strength and toughness is challenging due to their intrinsic conflicts. Herein, we report a simultaneous improvement in strength and toughness of heterocyclic aramid fibers by 26% and 66%, respectively, via in situ polymerizing small amount (0.05 wt%) of short aminated single-walled carbon nanotube (SWNT) into heterocyclic aramid fibers, yielding 6.44 ± 0.11 GPa in tensile strength and 184.0 ± 11.4 MJ m−3 in toughness. Combined experimental evidences and atomistic simulations, it was uncovered that short aminated SWNTs with favorable dispersity and alignment significantly improve the crystallinity and orientation degree of heterocyclic aramid chains by a scope of 8.6 nm, and the in situ polymerization between short aminated SWNTs and heterocyclic aramid monomers increases the length of polymer chains and the interfacial interaction therein to promote stress transfer and suppress the strain localization. These two effects account for the simultaneous improvement in strength and toughness of heterocyclic aramid fibers via small addition of short aminated SWNTs. This composite manner of “small addition, big gains” through global optimization should guide further work on improving the strength and toughness of composites.
Read moreAbstract Crystal‐facet heterojunction engineering of mesoporous nanoreactors with highly redox‐active represents an efficacious strategy for the transformation of CO 2 into valuable C 2 products (e.g., C 2 H 4 ). Herein, hollow mesoporous cube‐like CuS nanoreactors (~860 nm) with controlled anisotropic crystal‐facets are prepared through an interfacial‐confined ion dynamic migration‐rearrangement strategy. The regulation of the S 2− ion concentration facilitates the modulation of the highly active (110) to (100) crystal‐facet ratios from 0.119 to 0.288, and induces the formation of anisotropic crystal‐facet heterojunctions. The controllable crystal‐facet heterojunctions trigger the directional charge carrier migration, and are accompanied with the formation of tandem S‐defect sites (Cu 0 ‐S 1 @S 3 ). Both of them promote the efficient electron‐hole pair dissociation and attain asymmetric C−C coupling. The hollow mesoporous CuS nanoreactors with optimized crystal‐facet ratio of 0.224 (HMe‐CuS‐3) deliver a high selectivity of 72.7 % for the photocatalytic reduction of CO 2 to acetylene (C 2 H 2 ). Further constructed Au‐(110) and Co 3 O 4 ‐(100) spatially separated cascade nanoreactors (SS‐Au@Co 3 O 4 ‐CuS) achieve CO 2 ‐C 2 H 4 photoreduction, in which the Co‐sites enhance H 2 O dissociation to provide protons and the protonation of *CO to *COH. The *COH is further captured by Au‐sites to accomplish the asymmetric *CO‐*COH coupling and subsequent protonation, ensuring a high C 2 H 4 generation rate of 4.11 μmol/g/h with a selectivity as high as 90.6 %.
Read moreAbstract Polyoxometalates (POMs), as a unique class well‐defined metal‐oxo clusters with excellent multielectron redox properties, have attracted extensive attention in the field of energy storage and conversion, but it is still challenging to achieve their highly uniform and stable monodispersed. In this study, for the first time, polyoxovanadate (POV) is used, (NH 4 ) 2 [V IV 3 V V 3 O 10 {NH 2 C(CH 2 O) 3 } 3 ] (tris‐V 6 O 19 ), as nodes and successfully obtain a 3D covalent polyoxovanadate‐organic framework through a green hydrothermal synthesis method, termed POF‐1. Total scattering atomic pair distribution function analysis confirms that POF‐1 has a noninterpenetrated diamond‐like framework, fully exposing the monodispersed tris‐V 6 O 19 , effectively utilizing the active components of V IV /V V and enhancing surface mass transfer. Notably, POF‐1 demonstrates exceptional performance in lithium‐ion batteries, achieving a high reversible capacity of 887.4 mAh g −1 at 0.1 A g −1 and retaining over 92% capacity at 1 C during 1000 cycles. Electrochemistry mechanism and density functional theory calculations reveal that V centers in tris‐V 6 O 19 and carbonyls (C═O) in BDOEB linkers are the main active sites, with each POF‐1 fragment capable of storing up to 14 Li + . This study opens a new pathway for the efficient and green synthesis of new 3D well‐defined POM‐organic frameworks, and shows great application prospect in the field of energy storage.
Read moreDue to complexities from the interaction between steel tube and concrete filling of concrete-filled steel tubular (CFST) columns, their strengths are very complicated, which is a highly nonlinear relation with material strengths and geometry. Categorical gradient Boosting (CatBoost), which is advanced boosting machine, is presented to solve the problems. A total of 3103 tests, which is divided in four datasets, is trained and tested the learners to determine the ultimate axial strength as the output variable while the strength of materials (concrete and steel) and geometry (e.g., diameters/width/heights, thickness, effective length, eccentricities) are the input ones. The comparison of the present results from 10-fold cross validation and those from the code predictions (AISC 360-16, Eurocode 4 and AS/NZS 2327) and previous study shows very high prediction accuracy in terms of coefficient of determination (R2), which is the lowest value (R2 = 0.964) for Dataset 2 and the highest one (R2 = 0.996) for Dataset 1. While the predictions from three codes beyond material limit and slenderness are less conservative than those within it, CatBoost provides nearly similar experiment results with the mean values as unity without any limits. This algorithm can be used to predict an accurate strength of CFST columns.
Read moreConverting CO2 into carbonaceous fuels via photocatalysis represents an appealing strategy to simultaneously alleviate the energy crisis and associated environmental problems, yet designing with high photoreduction activity catalysts remains a compelling challenge. Here, combining the merits of highly porous structure and maximum atomic efficiency, we rationally constructed covalent triazine-based frameworks (CTFs) anchoring copper single atoms (Cu−SA/CTF) photocatalysts for efficient CO2 conversion. The Cu single atoms were visualized by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images and coordination structure of Cu−N−C2 sites was revealed by extended X-ray absorption fine structure (EXAFS) analyses. The as-prepared Cu−SA/CTF photocatalysts exhibited superior photocatalytic CO2 conversion to CH4 performance associated with a high selectivity of 98.31%. Significantly, the introduction of Cu single atoms endowed the Cu−SA/CTF catalysts with increased CO2 adsorption capacity, strengthened visible light responsive ability, and improved the photogenerated carriers separation efficiency, thus enhancing the photocatalytic activity. This work provides useful guidelines for designing robust visible light responsive photoreduction CO2 catalysts on the atomic scale.
Read moreAbstract Single‐atom nanozymes (SAzymes) can effectively mimic the metal active centers of natural enzymes at the atomic level owing to their atomically dispersed active sites, thereby maximizing atom utilization efficiency and density of active sites. Hence, SAzymes can be considered the most promising candidates to replace natural enzymes. Herein, a PEGylated mesoporous Mn‐based single‐atom nanozyme (PmMn/SAE) employing a coordination‐assisted polymerization pyrolysis strategy that uses polydopamine for photothermal‐augmented nanocatalytic therapy is designed. PmMn/SAE exhibits excellent multiple enzymatic performance, including catalase‐like, oxidase‐like, and peroxidase (POD)‐like performance, due to the atomically dispersed Mn active species. As a result, PmMn/SAE not only catalyzes the decomposition of endogenous H 2 O 2 to generate O 2 for relieving hypoxia inside the tumor but also transfers electrons to O 2 to produce superoxide radicals to kill tumor cells. Meanwhile, PmMn/SAE is able to trigger Fenton‐like reactions to generate highly toxic hydroxyl radicals to induce cancer cell apoptosis. The POD‐like catalytic mechanism of mMn/SAE is revealed using experimental results and density functional theory. Furthermor, PmMn/SAE shows good photothermal conversion efficiency (η = 22.1%) in the second near‐infrared region (1064 nm). Both the in vitro and in vivo experimental results indicate that PmMn/SAE can effectively kill cancer cells through photothermal‐enhanced catalytic therapy.
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