Nanozyme Catalytic Performance Enhancement through Defect and Electronic Structure Regulation of Metal-Doped NiCo2O4@Pd.

Spinel oxides have emerged as a promising candidate in the realm of nanozymes with variable oxidation states, while their limited active sites and low conductivity hinder further application. In this work, we synthesize a series of metal-doped NiCo2O4 nanospheres decorated with Pd, which are deployed as highly efficient nanozymes for the detection of cancer biomarkers. Through meticulous modulation of the molar ratio between NiCo2O4 and Pd, we orchestrated precise control over the oxygen vacancies and electronic structure within the nanozymes, a key factor in amplifying the catalytic prowess. Leveraging the superior H2O2 reduction catalytic properties of Fe-NiCo2O4@Pd, we have successfully implemented its application in the electrochemical detection of biomarkers, achieving unparalleled analytical performance, much higher than that of Pd/C and other reported nanozymes. This research paves the way for innovative electron modification strategies in the design of high-performance nanozymes, presenting a formidable tool for clinical diagnostic analyses.

Chitin/Chitosan Nanofibers Toward a Sustainable Future: From Hierarchical Structural Regulation to Functionalization Applications.

Owing to its multiple fascinating properties of renewability, biodegradability, biocompatibility, and antibacterial activity, chitin is expected to become a green cornerstone of next-generation functional materials. Chitin nanofibers, as building blocks, form multiscale hierarchical structures spanning nano- and macrolevels in living organisms, which pave the way for sophisticated functions. Therefore, from a biomimetic perspective, exploiting chitin nanofibers for use in multifunctional, high-performance materials is a promising approach. Here, we first summarize the latest advances in the multiscale hierarchical structure assembly mode of chitin and its derivative nanofibers, including top-down exfoliation and bottom-up synthesis. Subsequently, we emphasize the environmental impacts of these methods, which are crucial for whether chitin nanofibers can truly contribute to a more eco-friendly era. Furthermore, the latest progress of chitin nanofibers in environmental and medical applications is also discussed. Finally, the potential challenges and tailored solutions of chitin nanofibers are further proposed, covering raw material, structure, function, manufacturing, policies, etc.

Structure and Electron Engineering for Nitrate Electrocatalysis to Ammonia: Identification and Modification of Active Sites in Spinel Oxides.

Cobalt spinel oxides, which consist of tetrahedral site (AO4) and octahedral site (BO6), are a potential group of transition metal oxides (TMO) for electrocatalytic nitrate reduction reactions to ammonia (NRA). Identifying the true active site in spinel oxides is crucial to designing advanced catalysts. This work reveals that the CoO6 site is the dominant site for NRA through the site substitution strategy. The suitable electronic configuration of Co at the octahedral site leads to a stronger interaction between the Co d-orbital and the O p-orbital in O-containing intermediates, resulting in a high-efficiency nitrate-to-ammonia reduction. Furthermore, the substitution of metallic elements at the AO4 site can affect the charge density at the BO6 site via the structure of A-O-B. Thereafter, Ni and Cu are introduced to replace the tetrahedral site in spinel oxides and optimize the electronic structure of CoO6. As a result, NiCo2O4 exhibits the best activity for NRA with an outstanding yield of NH3 (15.49 mg cm-2 h-1) and FE (99.89%). This study introduces a novel paradigm for identifying the active site and proposes an approach for constructing high-efficiency electrocatalysts for NRA.

Constructing Metal-Organic Framework Films with Adjustable Electronic Properties on Hematite Photoanode for Boosting Photogenerated Carrier Transport.

Hematite (α-Fe2O3) has become a research hotspot in the field of photoelectrochemical water splitting (PEC-WS), but the low photogenerated carrier separation efficiency limits further application. The electronic structure regulation, such as element doping and organic functional groups with different electrical properties, is applied to alleviate the problems of poor electrical conductivity, interface defects, and band mismatch. Herein, α-Fe2O3 photoanodes are modified to regulate their electric structures and improve photogenerated carrier transport by the bimetallic metal-organic frameworks (MOFs), which are constructed with Fe/Ni and terephthalate (BDC) with 2-substitution of different organic functional groups (─H, ─Br, ─NO2 and ─NH2). The α-Fe2O3 photoanode loaded with FeNi-NH2BDC MOF catalyst exhibits the optimal photocurrent density (2 mA cm-2) at 1.23 VRHE, which is 2.33 times that of the pure α-Fe2O3 photoanode. The detailed PEC analyses demonstrate that the bimetallic synergistic effect between Fe and Ni can improve the conductivity and inhibit the photogenerated carrier recombination of α-Fe2O3 photoanodes. The ─NH2 group as an electron-donor group can effectively regulate the electron distribution and band structure of α-Fe2O3 photoanodes to prolong the lifetime of photogenerated holes, which facilitates photogenerated carrier transport and further enhances the PEC-WS performance of α-Fe2O3 photoanode.

Tuning Octahedron Sites of CoV2O4 via Cationic Competition for Efficient Oxygen Evolution Reaction.

Doping transition metal oxide spinels with metal ions represents a significant strategy for optimizing the electronic structure of electrocatalysts. Herein, a bimetallic Fe and Ru doping strategy to fine-tune the crystal structure of CoV2O4 spinel for highly enhanced oxygen evolution reaction (OER) is presented performance. The incorporation of Fe and Ru is observed at octahedral sites within the CoV2O4 structure, effectively modulating the electronic configuration of Co. Density functional theory calculations have confirmed that Fe acts as a novel reactive site, replacing V. Additionally, the synergistic effect of Fe, Co, and Ru effectively optimizes the Gibbs free energy of the intermediate species, reduces the reaction energy barrier, and accelerates the kinetics toward OER. As expected, the best-performing CoVFe0.5Ru0.5O4 displays a low overpotential of 240 mV (@10 mA cm-2) and a remarkably low Tafel slope of 38.9 mV dec-1, surpassing that of commercial RuO2. Moreover, it demonstrates outstanding long-term durability lasting for 72 h. This study provides valuable insights for the design of highly active polymetallic spinel electrocatalysts for energy conversion applications.

Customization of Manganese Oxide Cathodes via Precise Electrochemical Lithium-Ion Intercalation for Diverse Zinc-Ion Batteries.

Manganese oxide-based aqueous zinc-ion batteries (ZIBs) are attractive energy storage devices, owing to their good safety, low cost, and ecofriendly features. However, various critical issues, including poor conductivity, sluggish reaction kinetics, and unstable structure still restrict their further development. Oxygen defect engineering is an effective strategy to improve the electrochemical performance of manganese oxides, but challenging in the accurate regulation of oxygen defects. In this work, an effective and controllable defect engineering strategy-controllable electrochemical lithium-ion intercalation - is proposed to tackle this issue. The incorporation of lithium ions and oxygen defects can promote the conductivity, lattice spacing, and structural stability of Mn2O3 (MO), thus improving its capacity (232.7 mAh g-1), rate performance, and long-term cycling stability (99.0% capacity retention after 3000 cycles). Interestingly, the optimal ratio of intercalated lithium-ion varies at different temperature or mass-loading of MO, which provides the possibility to customize diverse ZIBs to meet different application conditions. In addition, the fabricated ZIBs present good flexibility, superior safety, and admirable adaptability under extreme temperatures (-20-100 °C). This work provides an inspiration on the structural customization of metal oxide nanomaterials for diverse ZIBs, and sheds light on the construction of future portable electronics.

Anion Structure Regulation of Cobalt Silicate Hydroxide Endowing Boosted Oxygen Evolution Reaction.

Transition metal silicates (TMSs) are attempted for the electrocatalyst of oxygen evolution reaction (OER) due to their special layered structure in recent years. However, defects such as low theoretical activity and conductivity limit their application. Researchers always prefer to composite TMSs with other functional materials to make up for their deficiency, but rarely focus on the effect of intrinsic structure adjustment on their catalytic activity, especially anion structure regulation. Herein, applying the method of interference hydrolysis and vacancy reserve, new silicate vacancies (anionic regulation) are introduced in cobalt silicate hydroxide (CoSi), named SV-CoSi, to enlarge the number and enhance the activity of catalytic sites. The overpotential of SV-CoSi declines to 301 mV at 10 mA cm-2 compared to 438 mV of CoSi. Source of such improvement is verified to be not only the increase of active sites, but also the positive effect on the intrinsic activity due to the enhancement of cobalt-oxygen covalence with the variation of anion structure by density functional theory (DFT) method. This work demonstrates that the feasible intrinsic anion structure regulation can improve OER performance of TMSs and provides an effective idea for the development of non-noble metal catalyst for OER.

Design of Atomically Dispersed CoN4 Sites and Co Clusters for Synergistically Enhanced Oxygen Reduction Electrocatalysis.

Constructing dual-site catalysts consisting of atomically dispersed metal single atoms and metal atomic clusters (MACs) is a promising approach to further boost the catalytic activity for oxygen reduction reaction (ORR). Herein, a porous CoSA-AC@SNC featuring the coexistence of Co single-atom sites (CoN4) and S-coordinated Co atomic clusters (SCo6) in S, N co-doped carbon substrate is successfully synthesized by using porphyrinic metal-organic framework (Co-TPyP MOF) as the precursor. The introduction of the sulfur source creates abundant microstructural defects to anchor Co metal clusters, thus modulating the electronic structure of its surrounding carbon substrate. The synergistic effect between the two types of active sites and structural advantages, in turn, results in high ORR performance of CoSA-AC@SNC with half-wave potential (E1/2) of 0.86 V and Tafel slope of 50.17 mV dec-1. Density functional theory (DFT) calculations also support the synergistic effect between CoN4 and SCo6 by detailing the catalytic mechanism for the improved ORR performance. The as-fabricated Zn-air battery (ZAB) using CoSA-AC@SNC demonstrates impressive peak power density of 174.1 mW cm-2 and charge/discharge durability for 148 h. This work provides a facile synthesis route for dual-site catalysts and can be extended to the development of other efficient atomically dispersed metal-based electrocatalysts.

Boosting the Structural Reversibility of Layered Oxide Cathode for Realizing Long-Term Cycle Life Through Electronic Structure Regulation.

O3-type layered oxide cathode exhibits great application potential for practical sodium-ion batteries, due to its cost-effectiveness, abundant sodium and manganese resources, and high theoretical capacity. However, the irreversible phase transition, coupled with rapid capacity decay, which is primarily attributed to the Jahn-Teller effect of Mn3+, remains a significant bottleneck for commercial application. Additionally, the sluggish kinetics during the (de)sodiation process require urgent improvement. Herein, an electronic structure regulation strategy is proposed by low-valence Li/Cu co-substitution to address these issues. The roles of Li/Cu on the electronic structure, structural evolution, and electrochemical properties in the Na0.96Ni0.22Fe0.2Mn0.5Li0.04Cu0.04O2 (NFMLC) cathode are comprehensively explored through systematic in situ/ex situ characterization techniques and theoretical calculations. The results reveal that this strategy effectively activates more Ni2+/3+ and Fe3+/4+ redox reactions above 2.5 V, while suppressing Mn3+/4+ redox activity below 2.5 V, thereby achieving highly structural reversibility. Therefore, the NFMLC electrode displays excellent long-term cycling stability (81.5% capacity retention after 2000 cycles at 5 C), and significantly enhanced rate performance (from 45.5% to 80.4% under a ratio of 5 C to 0.5 C). This work provides a valuable perspective on the design of low-cost, long-life, and high-performance layered oxide cathodes for practical sodium-ion batteries.

Field-Assisted Regulation Induced by Cobalt-Doped ZnO for Dendrite-Free Lithium Metal Anodes.

Lithium metal batteries are deemed as an optimal candidate for the next generation of durable energy storage devices. However, the growth of lithium dendrite and significant volume expansion pose as obstacles that impede the application of lithium metal batteries. In this work, a functional copper current collector was designed by coating it with Co-doped ZnO (Co/ZnO) to enhance the lithiophilicity through local electric fields and built-in magnetic fields induced by the ferromagnetic material. The incorporation of Co not only induces a local electric field and thus accelerating electron transfer, but also imparts the ferromagnetic behavior to ZnO, resulting in an internal magnetic field to regulate the dynamic trajectory. Profiting from the above advantages, the symmetric cells have excellent cycle stability in 1 mA cm-2 and 1 mAh cm-2 , maintaining ultra-low voltage for over 2000 h. This study provides a realizable pathway for next-generation current collector of copper modification.

Understanding the Role of Titanium Metal-Organic Framework Nanosheets in Modulating Anode Chemistry for Aqueous Zinc-Ion Batteries.

Aqueous zinc-ion batteries have attracted a continually increasing level of interest for large-scale energy storage because they are highly safe and have high energy density and abundant reserves. However, Zn anodes face significant challenges such as severe dendrite growth and hydrogen evolution reaction (HER). We here propose an efficient Zn2+ sieve strategy for modulating the anode chemistry using two-dimensional NH2-MIL-125 (Ti) metal-organic framework (MOF) nanosheets. Theoretical investigations reveal the crucial role of the Ti MOF in regulating Zn2+ solvation structures for fast diffusion and uniform deposition and decreasing HER reactivity. The structure of the nanosheets enables abundant accessible desolvation sites and shortened ionic pathways. As a result, the MOF nanosheet-protected Zn anode exhibited greatly improved cycling stability in both symmetric cells and full cells. Operando optical monitoring and postmortem analysis revealed effective suppression of dendrite growth and HER by Ti MOF nanosheets. This anti-HER MOF-enabled Zn2+ sieve strategy provides a viable Zn anode and provides new insights for optimizing aqueous batteries.

Super-Enhancers and Their Parts: From Prediction Efforts to Pathognomonic Status.

Super-enhancers (SEs) are regions of the genome that play a crucial regulatory role in gene expression by promoting large-scale transcriptional responses in various cell types and tissues. Recent research suggests that alterations in super-enhancer activity can contribute to the development and progression of various disorders. The aim of this research is to explore the multifaceted roles of super-enhancers in gene regulation and their significant implications for understanding and treating complex diseases. Here, we study and summarise the classification of super-enhancer constituents, their possible modes of interaction, and cross-regulation, including super-enhancer RNAs (seRNAs). We try to investigate the opportunity of SE dynamics prediction based on the hierarchy of enhancer single elements (enhancers) and their aggregated action. To further our understanding, we conducted an in silico experiment to compare and differentiate between super-enhancers and locus-control regions (LCRs), shedding light on the enigmatic relationship between LCRs and SEs within the human genome. Particular attention is paid to the classification of specific mechanisms and their diversity, exemplified by various oncological, cardiovascular, and immunological diseases, as well as an overview of several anti-SE therapies. Overall, the work presents a comprehensive analysis of super-enhancers across different diseases, aiming to provide insights into their regulatory roles and may act as a rationale for future clinical interventions targeting these regulatory elements.

Recent Advances in Regulating Ceramic Monolithic Catalyst Structure for Preferential Oxidation of CO in H2.

Preferential oxidation of CO (CO-PROX) has tremendous significance in purifying hydrogen for fuel cells to avoid catalyst poisoning by CO molecules. Traditional powder catalysts face numerous challenges, including high pressure drop, aggregation tendency, hotspot formation, poor mass and heat transfer efficiency, and inadequate thermal stability. Accordingly, ceramic monolithic catalysts, known as their excellent thermal stability, high surface area, and superior mass and heat transfer characteristics, are gaining increasing research attention. This review examines recent studies on ceramic monolithic catalysts in CO-PROX, placing emphasis on the regulation of active sites (e.g., precious metals like Pt and Au, and non-precious metals like CuO and CeO2), monolith structures, and coating strategies. In addition, the structure-catalytic performance relationships, as well as the potential and limitations of different ceramic monolithic catalysts in practical application, are discussed. Finally, the challenges of monolithic catalysts and future research prospects in CO-PROX reactions are highlighted.

Electronic Structure Regulated Nickel-Cobalt Bimetal Phosphide Nanoneedles for Efficient Overall Water Splitting.

Transition metal phosphides (TMPs) have been widely studied for water decomposition for their monocatalytic property for anodic or cathodic reactions. However, their bifunctional catalytic activity still remains a major challenge. Herein, hexagonal nickel-cobalt bimetallic phosphide nanoneedles with 1-3 µm length and 15-30 nm diameter supported on NF (NixCo2-xP NDs/NF) with adjusted electron structure have been successfully prepared. The overall alkaline water electrolyzer composed of the optimal anode (Ni0.67Co1.33P NDs/NF) and cathode (Ni1.01Co0.99P NDs/NF) provide 100 mA cm-2 at 1.62 V. Gibbs Free Energy for reaction paths proves that the active site in the hydrogen evolution reaction (HER) is Ni and the oxygen evolution reaction (OER) is Co in NixCo2-xP, respectively. In the HER process, Co-doping can result in an apparent accumulation of charge around Ni active sites in favor of promoting HER activity of Ni sites, and ΔGH* of 0.19 eV is achieved. In the OER process, the abundant electron transfer around Co-active sites results in the excellent ability to adsorb and desorb *O and *OOH intermediates and an effectively reduced ∆GRDS of 0.37 eV. This research explains the regulation of electronic structure change on the active sites of bimetallic materials and provides an effective way to design a stable and effective electrocatalytic decomposition of alkaline water.

Correlation between Heteroatom Coordination and Hydrogen Evolution for Single-site Pt on Carbon-based Nanocages.

The electrocatalytic performance of single-site catalysts (SSCs) is closely correlated with the electronic structure of metal atoms. Herein we construct a series of Pt SSCs on heteroatom-doped hierarchical carbon nanocages, which exhibit increasing hydrogen evolution reaction (HER) activities along S-doped, P-doped, undoped and N-doped supports. Theoretical simulation indicates a multi-H-atom adsorption process on Pt SSCs due to the low coordination, and a reasonable descriptor is figured out to evaluate the HER activities. Relative to C-coordinated Pt, N-coordinated Pt has higher reactivity due to the electron transfer of N-to-Pt, which enriches the density of states of Pt 5d orbital near the Fermi level and facilitates the capturing of protons, just the opposite to the situations for P- and S-coordinated ones. The stable N-coordinated Pt originates from the kinetic stability throughout the multi-H-atom adsorption process. This finding provides a significant guidance for rational design of advanced Pt SSCs on carbon-based supports.

Partial Sulphidation to Regulate Coordination Structure of Single Nickel Atoms on Graphitic Carbon Nitride for Efficient Solar H2 Evolution.

To develop a non-precious highly efficient cocatalyst to replace Pt on graphitic carbon nitride (g-C3 N4 ) for solar H2 production is great significant, but still remains a huge challenge. The emerging single-atom catalyst presents a promising strategy for developing highly efficient non-precious cocatalyst owing to its unique adjustability of local coordination environment and electronic structure. Herein, this work presents a facile approach to achieve single Ni sites (Ni1 -N2 S) with unique local coordination structure featuring one Ni atom coordinated with two nitrogen atoms and one sulfur atom, confirmed by high-angle annular dark-field scanning transmission electron microscopy, X-ray absorption spectroscopy, and density functional theory calculation. Thanks to the unique electron structure of Ni1 -N2 S sites, the 1095 µmol g-1 h-1 of high H2 evolution rate with 4.1% of apparent quantum yield at 420 nm are achieved. This work paves a pathway for designing a highly efficient non-precious transition metal cocatalyst for photocatalytic H2 evolution.

Turn "Waste" Into Wealth: MoO2 @coal Gangue Electrocatalyst with Amorphous/Crystalline Heterostructure for Efficient Li-O2 Batteries.

Unreasonable accumulation of coal gangue in mining area has become the major source of global pollution. Probing the high-valued utilization of coal gangue has become a key approach to address the problem. Herein, a promising catalyst of MoO2 @coal gangue with amorphous/crystalline heterostructure derived from mine solid waste, which acts as an efficient cathode for Li-O2 batteries is first reported. Impressively, the as-prepared catalyst exhibits a favorable initial discharge capacity of 9748 mAh g-1 and promising long-term cyclic stability over 2200 h. Experimental results coupled with density functional theory (DFT) analysis reveal that the synergistic interaction between high-activity MoO2 and stable SiO2 , unique amorphous/crystalline heterostructure and the modified interfacial adsorption of LiO2 intermediate are critical factors in promoting the electrochemical performance. This work provides a new insight to design marked electrocatalysts by mine solid waste for Li-O2 batteries.

Embedded Mo/Mn Atomic Regulation for Durable Acidity-Reinforced HZSM-5 Catalyst toward Energy-Efficient Amine Regeneration.

Metal-molecular sieve composites with high acidity are promising solid acid catalysts (SACs) for accelerating sluggish CO2 desorption processes and reducing the energy consumption of CO2 chemisorption systems. However, the production of such SACs through conventional approaches such as loading or ion-exchange methods often leads to uncontrolled and unstable metal distribution on the catalysts, which limits their pore structure regulation and catalytic performance. In this study, we demonstrated a feasible strategy for improving the durability, surface chemical activity, and pore structure of metal-doped HZSM-5 through bimetallic Mo/Mn modification. This strategy involves the immobilization of Mo-O-Mn species confined in an MFI structure by regulating MoO42- anions and Mn2+ cations. The embedded Mn/Mo species of low valence can strongly induce electron transfer and increase the density of compensatory H+ on the MoMn@H catalyst, thereby reducing the CO2 desorption temperature by 8.27 °C and energy consumption by 37% in comparison to a blank. The durability enhancement and activity regulation method used in this study is expected to advance the rational synthesis of metal-molecular sieve composites for energy-efficient CO2 capture using amine regeneration technology.

Imidazole-octyl mixed-mode stationary phase based on macroporous silica for the purification of ovomucoid and ovotransferrin.

A process-simplified hard template approach was established to synthesize the monodisperse macroporous silica microspheres with homogeneous structures by twice alkali-thermal treatment and calcination routes. Porous vinyl-functionalized polysesquioxane microspheres (V-PMSQ) were synthesized through a hydrolyzation-polycondensation method and used as templates. The template particles with large aperture and high pore volume were obtained by adjusting the pH value and reaction time of the twice alkali-thermal reaction. After calcination, monodisperse silica microspheres with an average pore size of 30 nm, homogeneous pore structures, and narrow particle size distribution were fabricated, which can be directly used as chromatographic matrices without classification. After that, a new reversed-phase/strong anion-exchange (RP/SAX) mixed-mode stationary phase Sil-S-VOIM was prepared by bonding the 1-vinyl-3-octyl-imidazole ligands to the above silica microspheres through a "thiol-ene" click reaction. The performance of the Sil-S-VOIM column was evaluated by one acidic protein (transferrin) and two basic proteins (lysozyme, α-chymotrypsin) and compared to a single imidazole-modified Sil-S-VIM column and an octyl-modified Sil-C8 column, respectively. Due to the synergistic effect of electrostatic repulsion and hydrophobic interactions, baseline separations of the above proteins were observed only on the Sil-S-VOIM column, with resolutions of 2.55 and 2.01 between lysozyme and transferrin, and between transferrin and α-chymotrypsin, respectively, indicating good selectivity and separation ability compared with single-mode stationary phases. It was applied to the isolation of egg white samples with peaks identified by SDS-PAGE and MALDI-TOF-MS. The results showed that the selective retention and isolation of ovomucoid and ovotransferrin were successfully achieved, with yields of 78.8% and 67.2%, respectively. The protocol described in this work is simpler, faster, and has higher protein recovery. Overall, this new mixed-mode stationary phase provided a promising potential for the separation and determination of intact proteins.

Manipulating the Electronic Structure of Graphite Intercalation Compounds for Boosting the Bifunctional Oxygen Catalytic Performance.

Developing highly efficient bifunctional catalysts for the oxygen reduction and oxygen evolution reaction (ORR/OER) can open possibilities for future zinc air batteries (ZABs). Herein, cost-effective and highly conductive few-layer ferric and nickel chloride co-intercalated graphite intercalation compounds (FeCl3 -NiCl2 -GIC) are designed as bifunctional oxygen catalysts for ZAB. The optimized few-layer FeCl3 -NiCl2 -GIC catalyst exhibits a small overpotential of 276 mV at 10 mA cm-2 for the OER and achieves a high onset potential of 0.89 V for the ORR. The theoretical analysis demonstrates the electron-rich state on the carbon layers of FeCl3 -NiCl2 -GIC during the catalytic process favors the kinetics of electron transfer and lowers the absorption energy barriers for intermediates. Impressively, the ZAB assembled with few-layer FeCl3 -NiCl2 -GIC catalyst displays a 160 h cycling stability and a high energy efficiency of 72.6%. This work also suggests the possibility of utilizing layer electronic structure regulation on graphite intercalation compounds as effective bifunctional catalysts for ZABs.