Urchin-like Structure Research Articles

Simulation, prediction and optimization for synthesis and heavy metals adsorption of schwertmannite by machine learning

Due to its sea urchin-like structure, Schwertmannite is commonly applied for heavy metals (HMs) pollutant adsorption. The adsorption influence parameters of Schwertmannite are numerous, the traditional experimental enumeration is powerless. In recent years, machine learning (ML) has been gradually employed for adsorbent materials, but there is no comprehensive research on the Schwertmannite adsorbent. In this paper, 27 features and 814 groups of experimental data were used to systematically analyze the adsorption modeling of Schwertmannite first time. The results indicated that the adsorption capacity of Schwertmannite was better predicted by the Random Forest (RF) model (the R2 was 0.874). Then, the RF model was used to analyze the features importance that affects the adsorption of HMs by Schwertmannite. And the importance of Schwertmannite synthesis conditions, Schwertmannite characteristics, adsorption environment, and HMs properties were 11.88%, 30.01%, 48.26%, and 8.19% respectively. Moreover, the synthesis and adsorption conditions of Schwertmannite were predicted and optimized based on RF model, it was predicted that the better synthesis method of Schwertmannite was biological oxidation > Fe2+ oxidation > Fe3+ hydrolysis. Finally, a predictive Graphical User Interface Web Page for Schwertmannite-HMs was developed. We hope that this paper can promote the integration of machine learning and Schwertmannite.

Hexagonal Prism-Shaped AIE-Active MOFs as Coreactant-Free Electrochemiluminescence Luminophores Coupled with Hollow Cu2-xO@Pd Heterostructures as Efficient Quenching Probes for Sensitive Biosensing.

For most self-luminous metal-organic framework (MOF)-involved electrochemiluminescence (ECL) systems, the integration of exogenous coreactants is indispensable to promote ECL efficiency. However, the introduction of a coreactant into an electrolyte would result in poor stability, thereby inevitably affecting analytical accuracy. Herein, by employing aggregation-induced emission luminogens as ligands, we first synthesized one hexagonal prism-shaped MOF that displays robust and steady ECL signal without an exogenous coreactant. Furthermore, adenosine triphosphate (ATP), as the target analyte, can be fixed on the electrode surface directly owing to the strong coordination between Zr4+ and phosphate groups. According to the ECL resonance energy transfer effect, hollow Cu2-xO@Pd heterostructures are conveniently prepared and act as efficient quenching probes. Remarkably, the resultant urchin-like hollow structure could provide more active sites to anchor ATP aptamers, thus enhancing the ECL quenching efficiency. In this manner, an elaborate coreactant-free ECL system was developed to detect ATP, which demonstrates a remarkable detection limit of 0.17 nM, as well as excellent stability and reproducibility. The present work offers significant enlightenment for the further evolution of advanced ECL systems integrated with MOF-based luminophores.

Dual Plasmons with Bioinspired 3D Network Structure Enabling Ultrahigh Efficient Solar Steam Generation.

Plasmonic nanomaterials such as Au, Ag, and Cu are widely recognized for their strong light-matter interactions, making them promising photothermal materials for solar steam generation. However, their practical use in water evaporation is significantly limited by the trade-off between high costs and poor stability. In this regard, we introduce a novel, nonmetallic dual plasmonic TiN/MoO3-x composite. This composite features a three-dimensional, urchin-like biomimetic structure, with plasmonic TiN nanoparticles embedded within a network of plasmonic MoO3-x nanorods. As a solar absorber, the TiN/MoO3-x composite achieves a high evaporation rate of ∼2.05 kg m-2 h-1 with an energy efficiency up to 106.7% under 1 sun illumination, outperforming the state-of-the-art plasmonic systems. The high photothermal stability and unique dual plasmonic nanostructure of the TiN/MoO3-x composite are demonstrated by advanced in situ laser-heating transmission electron microscopy and photon-induced near-field electron microscopy/electron energy-loss spectroscopy, respectively. This work provides new inspiration for the design of plasmonic materials.

Enhancing the capacitance of carbonized wood by regulating the morphology and valence state of guest electrochemically active materials

Using bottom-top methodology to load metal oxides with high pseudocapacitive activity onto carbonized wood (CW) is an efficient strategy to fabricate electrodes with large capacitance, while the morphology and metal valence in metal oxides are as important as their content but have received little attention. Herein, a heating treatment integrating carbonization and activation processes is used on Cu2+ loaded natural wood to prepare CW/CuxOy electrodes in which CuxOy with pseudocapacitive activity and CW with a high specific surface area (SSA) of 832 m2/g and good electric conductivity of 1.25 S cm−1 are collaboratively achieving a capacitance of 430.5F/g at 150 mA g−1. Then, a constant potential method is utilized not only to regulate the valence state of Cu and Cu2+ in CuxOy to Cu+ with much higher pseudocapacitive activity, but also to convert the morphology of CuxOy from sphericity to urchin-like and cluster structure with more available active sites. Therefore, the optimized electrode achieves a greatly improved capacitance of 855F/g, and the fabricated supercapacitor delivers an energy density of 75.93 Wh kg−1 at 138 W kg−1. This work provides an approach to enhance the specific capacitance of metal oxides-based electrodes from a fresh perspective.

Synthesis of hollow urchin-like TiO2/N-GQDs composites and efficient photocatalytic degradation research on waste organic dyes

In order to enhance the visible light catalytic activity of TiO2 by broadening its photoresponse range, the TiO2/N-GQDs (TGs) composite catalysts with a three-dimensional hollow urchin-like structure were prepared by one-step hydrothermal method. The microstructure and photoelectric properties of the synthesized TGs composites were analyzed through a series of characterizations, and the performance in degrading organic dyes under visible light was investigated. The results demonstrated that the prepared composites effectively enhanced the visible light absorption spectrum of TiO2 by forming heterojunction. The degradation efficiency of organic dyes could reach 95.71% under visible light irradiation for 1 h, which further increased to 99.39% after 2 h. Additionally, the photocatalytic degradation process could be effectively accelerated under acid conditions. After 5 cycles of testing, the degradation efficiency of TGs composites on organic dyes was hardly reduced, indicating that they had great visible light catalytic activity and significant reusability.

Efficient broadband sea urchin-like Fe3O4@C electromagnetic wave absorbing materials

The development of electromagnetic wave absorbing materials is crucial for various applications. Carbon materials and ferrite materials were recognized as ideal candidates of absorbing agents due to their respective dielectric loss and magnetic loss capabilities. In this study, Fe3O4@C were prepared using hydrothermal carbonization coupling method. The microstructure and morphology of Fe3O4@C were studied using SEM, TEM, XRD and TG. The results showed that Fe3O4@C exhibited a hollow sea urchin-like structure. The molar ratio of carbon to iron sources in the raw materials significantly influenced the crystal structure of the product. The growth mechanism of sea urchin-like Fe3O4@C was proposed. The carbon content in Fe3O4@C increased with the increase of molar ratio of glucose and iron (III) sulfate. The Fe3O4@C with carbon content of 31.10 % exhibited optimal absorption performance, with a minimum reflection loss of −57.1 dB at a matching thickness of 5.10 mm and effective absorption bandwidth (EAB) of 4 GHz. Electromagnetic parameters and absorption performance could be adjusted by varying the molar ratio of glucose and iron (III) sulfate. The unique sea urchin-like structure enhanced multiple reflection of electromagnetic waves. Interface polarization, conductivity loss and synergistic effect between carbon and Fe3O4 also contributed to the favorable absorption properties.

Enhanced photoelectrochemical water splitting by a 3D hierarchical sea urchin-like structure: ZnO nanorod arrays on TiO2 hollow hemisphere

A hierarchical sea urchin-like hybrid metal oxide nanostructure of ZnO nanorods deposited on TiO2 porous hollow hemispheres with a thin zinc titanate interface layer is specifically designed and synthesized to form a combined type I straddling and type II staggered junctions. The HHSs, synthesized by electrospinning, facilitate light trapping and scattering. The ZnO nanorods offer a large surface area for improved surface oxidation kinetics. The interface layer of zinc titanate (ZnTiO3) between the TiO2 HHSs and ZnO nanorods regulates the charge separation in a closely coupled hierarchy structure of ZnO/ZnTiO3/TiO2. The synergistic effects of the improved light trapping, charge separation, and fast surface reaction kinetics result in a superior photoconversion efficiency of 1.07% for the photoelectrochemical water splitting with an outstanding photocurrent density of 2.8 mA cm−2 at 1.23 V versus RHE.

Cu(II)-Loaded Polydopamine-Coated Urchin-like Titanate Microspheres as a High-Performance IMAC Adsorbent for Hemoglobin Separation.

Immobilized metal ion affinity chromatography (IMAC) adsorbents generally have excellent affinity for histidine-rich proteins. However, the leaching of metal ions from the adsorbent usually affects its adsorption performance, which greatly affects the reusable performance of the adsorbent, resulting in many limitations in practical applications. Herein, a novel IMAC adsorbent, i.e., Cu(II)-loaded polydopamine-coated urchin-like titanate microspheres (Cu-PDA-UTMS), was prepared via metal coordination to make Cu ions uniformly decorate polydopamine-coated titanate microspheres. The as-synthesized microspheres exhibit an urchin-like structure, providing more binding sites for hemoglobin. Cu-PDA-UTMS exhibit favorable selectivity for hemoglobin adsorption and have a desirable adsorption capacity towards hemoglobin up to 2704.6 mg g-1. Using 0.1% CTAB as eluent, the adsorbed hemoglobin was easily eluted with a recovery rate of 86.8%. In addition, Cu-PDA-UTMS shows good reusability up to six cycles. In the end, the adsorption properties by Cu-PDA-UTMS towards hemoglobin from human blood samples were analyzed by SDS-PAGE. The results showed that Cu-PDA-UTMS are a high-performance IMAC adsorbent for hemoglobin separation, which provides a new method for the effective separation and purification of hemoglobin from complex biological samples.

Vacuum-solvent thermal synthesis of nickel foam-supported CuO-based sensor electrode for good electrochemical detection of nitrite

Given the bad effect of superfluous nitrites on biology/environment, engineering the fast, sensitive, and real-time quantification of nitrites matters to safeguard both the eco-system and human public health. Here, a CuO nanocatalyst self-supported on nickel foam (CuO@NF) was crafted via facilely fusing a vacuum solvent recipe with ambient thermal annealing. Various characterizations show that hollow sea urchin-like CuO structures were arrayed on substrate to feature a 3D porous motif and large specific surface area. Such traits promise the effective local wetting and enrichment of nitrite to augment the nitrate capture/contact capacity, underlying a highly sensitive electrochemical determination of nitrite. Specifically, a wide linear detection range can span 0.5 to 4250 μM, with a stable current response at a concentration as low as 0.5 μM nitrite. The detection limit or sensitivity is approximately 0.0287 mM or 2.402 mAmM−1 cm−2, respectively. This electrode was also successfully applied to detect the nitrite in complex samples like pickled vegetables with satisfactory recovery rates. Our study shows that the self-supported CuO sensor provides an ingenious tactic to build high-efficiency binderless electrodes for the electrochemical sensing applications.

Facile Synthesis of Ag-Doped Urchin-like MnO2 on Carbon Cloth for Supercapacitors.

Based on MnO2/carbon cloth (CC) composite materials, an Ag-doped MnO2 nanowire, self-assembled, urchin-like structure was synthesized in situ on the surface of CC using a simple method, and a novel and efficient flexible electrode material for supercapacitors was developed. The morphology, structure, elemental distribution, and pore distribution of the material were analyzed using SEM, TEM, XRD, XPS, and BET. The electrochemical performance was tested using cyclic voltammetry (CV) and galvanostatic charge/discharge (GCD). In the three-electrode system, GCD testing showed that the specific capacitance of the material reached 520.8 F/g at 0.5 A/g. After 2000 cycles at a current density of 1 A/g, the capacitance retention rate was 90.6%, demonstrating its enormous potential in the application of supercapacitor electrode materials.

Special atmosphere annealed Co3O4 bifunctional catalysts with oxygen defects for high-efficient water splitting

Electrochemical water splitting is widely recognized as an economical and sustainable method for producing high-purity hydrogen using renewable energy sources. Herein, we prepared 3D urchin-like sphere structures of Co3O4 to serve as an excellent bifunctional catalyst for overall water splitting. Different Co3O4 samples were directly synthesized on Ni foam through hydrothermal and annealing processes under various atmospheric conditions, leading to the formation of oxygen vacancies with varying concentrations. Specifically, the Co3O4/NF-Ar/O2 demonstrates outstanding catalytic performance for both OER (η20 = 269 mV) and HER (η10 = 135 mV), while maintaining excellent durability in 1 M KOH. Electrolysis cells employing Co3O4/NF-Ar/O2 as both anode and cathode demonstrate a low cell voltage of 1.56 V to achieve 10 mV cm−2 in alkaline conditions. The excellent catalytic performance can be mainly attributed to the urchin-like nanostructure and the appropriate concentration of oxygen vacancies. This research provides further insights into the application of the method to induce oxygen vacancies in low-cost and high-efficiency transition metal oxides (TMOs)-based catalysts for electrochemical reaction.

Collaborative electrospinning and ice-templating for sea urchin-inspired aerogel microsphere: Unraveling functional mechanisms in thermally conductive phase change composites

With the increased integration of electronic devices, effective heat management becomes imperative. Thermally conductive phase change composites play a vital role by efficiently conducting heat and utilizing matrix phase change for heat storage. Conventional materials encounter difficulties such as low thermal conductivity, restricted heat storage density, and vulnerability to leakage. This study presents a novel method combining electrospinning and ice-templating method to produce aerogel microspheres with sea urchin-like structures, resolving mentioned issues. The microspheres exhibit a radial microstructure and controllable size, serving as efficient fillers for the easy production of high-performance phase change materials. The microspheres are able to create an efficient interlocking mechanism with surface spike structures, forming a continuous thermal conduction and spatially confined network in the composite material. At a filler content of 43.9 vol%, the thermal conductivity of the Al aerogel microsphere/paraffin composite reaches a peak value of 3.2 W/mK, accompanied by a contact thermal resistance of 1.2 × 10−6 Km2/W. Subjecting the composite to elevated temperatures well above the matrix's phase change temperature preserves its structural stability. This work reports a new structured filler moulding method that supports the development of high performance thermally conductive phase change composites.

Urchin-like Ni[sbnd]Co hydroxide@tamarind seed biochar for high performance supercapacitor

This study introduces a novel composite material, U-NiCo-OH@TTBC, comprised of tamarind seed biochar (TTBC) and nickel-cobalt hydroxide, designed for high-performance supercapacitors. This composite exhibits a unique urchin-like structure with a specific surface area of 610 m2 g−1, facilitating efficient electron-ion transport and electrolyte diffusion. U-NiCo-OH@TTBC demonstrates an impressive storage capacity of 759 F g−1 at 1 A g−1, along with a specific capacitance of 158 F g−1. The symmetric device built with U-NiCo-OH@TTBC boasts power densities ranging from 787 to 7183 W kg−1 and energy densities between 16 and 54 Wh kg−1. Most notably, the device exhibits exceptional long-term cyclic stability, retaining 92 % of its performance after 10,000 charge-discharge cycles. This work highlights the potential of agricultural waste as sustainable carbon sources and their compatibility with metal hydroxides to create eco-friendly and durable supercapacitor electrodes.

Combined effects of sea urchin-like structure and mixed Cu+/Cu0 states on promoting C2 formation in electrocatalytic CO2 reduction

Combined effects of sea urchin-like structure and mixed Cu+/Cu0 states on promoting C2 formation in electrocatalytic CO2 reduction

Facile synthesis of hydroxylated triazine-based magnetic microporous organic network for ultrahigh adsorption of phenylurea herbicides: An experimental and density-functional theory study

Microporous organic networks (MONs) are highly porous materials that are particularly useful in analytical chemistry. However, the use of these materials is often limited by the functional groups available on their surface. Here, we described the polymerization of a sea urchin-like structure material at ambient temperature, that was functionalized with hydroxyl, carboxyl, and triazine groups and denoted as OH-COOH-MON-TEPT. A substantial proportion of OH-COOH-MON-TEPT was intricately decorated EDA-Fe3O4, creating a well-designed configuration (EDA-Fe3O4 @OH-COOH-MON-TEPT-EDC) for superior adsorption of the target analytes phenylurea herbicides (PUHs) via magnetic solid-phase extraction (MSPE). The proposed method showed remarkably low limits of detection ranging from 0.03 to 0.22 ng·L−1. Experimental investigations and theoretical analyses unveiled the adsorption mode between EDA-Fe3O4 @OH-COOH-MON-TEPT-EDC and PUHs. These findings establish a robust foundation for potential applications of EDA-Fe3O4 @OH-COOH-MON-TEPT-EDC in the analysis of various polar contaminants.

Urchin-like CoP3/Cu3P heterostructured nanorods supported on a 3D porous copper foam for high-performance non-enzymatic electrochemical dopamine sensors.

In this study, we developed a high-performance non-enzymatic electrochemical sensor based on urchin-like CoP3/Cu3P heterostructured nanorods supported on a three-dimensional porous copper foam, namely, CoP3/Cu3P NRs/CF, for the detection of dopamine. Benefiting from the promising intrinsic catalytic activities of CoP3 and Cu3P, urchin-like microsphere structures, and a large electrochemically active surface area for exposing numerous accessible catalytic active sites, the proposed CoP3/Cu3P NRs/CF shows extraordinary electrochemical response towards the electrocatalytic oxidation of dopamine. As a result, the CoP3/Cu3P NRs/CF sensing electrode has a broad detection window (from 0.2 to 2000 μM), low detection limit (0.51 μM), high electrochemical sensitivity (0.0105 mA μM-1 cm-2), excellent selectivity towards dopamine in the coexistence of some interfering species, and good stability for dopamine determination. More importantly, the CoP3/Cu3P NRs/CF catalyst also exhibits excellent catalytic activity, sensitivity, and selectivity for dopamine detection under simulated human body conditions at a physiological pH of 7.25 (0.1 M PBS) at 36.6 °C.

Effect of a mesoporous NiCo2O4 urchin-like structure catalyzed with a surface oxidized LiBH4 system for reversible hydrogen storage applications.

A mesoporous NiCo2O4 urchin-like structure was synthesized by applying a facile hydrothermal method. Different concentrations of NiCo2O4 urchin-like structures were mixed with a surface oxidized LiBH4 system using a wet-impregnation method, followed by heat treatment. The hydrogen storage capacity of LiBH4 + 25% NiCo2O4, LiBH4 + 50% NiCo2O4 and LiBH4 + 75% NiCo2O4 systems was investigated. Typically, hydrogenated LiBH4 + 25% NiCo2O4, LiBH4 + 50% NiCo2O4 and LiBH4 + 75% NiCo2O4 systems desorbed 2.85 wt%, 3.78 wt% and 3.91 wt% of hydrogen, respectively, at the dehydrogenation temperature ranging from room temperature (RT) to 275 °C. Further, the LiBH4 + 75% NiCo2O4 system exhibited better kinetics than other systems and released ∼5.8 wt% of hydrogen at a isothermal dehydrogenation temperature of 250 °C in 60 minutes. Hydrogen binding energies were calculated as 0.28 eV, 0.27 eV and 0.26 eV for LiBH4 + 25% NiCo2O4, LiBH4 + 50% NiCo2O4 and LiBH4 + 75% NiCo2O4 systems, respectively. Moreover, the calculated activation energies of LiBH4 + 25% NiCo2O4, LiBH4 + 50% NiCo2O4 and LiBH4 + 75% NiCo2O4 systems are 17.99 kJ mol-1, 17.03 kJ mol-1 and 16.92 kJ mol-1, respectively. The calculated BET (Brunauer-Emmett-Teller) surface area of NiCo2O4 and LiBH4 + 75% NiCo2O4 systems is 124.05 and 136.62 m2 g-1, respectively. These results showed that hydrogen sorption and desorption properties are significantly increased by the influence of mesoporous structure, lower binding energy and activation energy of LiBH4 + 75% NiCo2O4 system.

Oxygen vacancy tuning of porous urchin-like nickel cobaltite for improved bifunctional electrocatalysis

Proper regulating morphology and rationally distributing of active sites in a catalyst is crucial for improving its electrocatalytic performance. In this study, we synthesized a series of porous urchin-like NiCo2O4 structures through hydrothermal reaction and adjusted their morphologies and oxygen vacancies concentration by annealing them under different conditions. The resulting structure has interconnected pores that facilitate the fast transport of active species, assembled from many nanoneedles containing nanoparticles. Our results show that the porous urchin-like NiCo2O4 structure obtained after annealing at 400 °C under an argon atmosphere has the largest surface coverage area for redox species and the richest oxygen vacancies. This configuration demonstrates excellent performance in both methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR) in alkaline solution. Our findings offer a facile pathway to optimizing active sites on urchin-like NiCo2O4 structures, which could serve as bifunctional electrocatalysts for direct methanol fuel cells (DMFCs).

Highly Salt-tolerant hydrogen evolution reaction based on dendritic urchin-like MoC/MoS2 heterojunction in seawater

The direct electrolysis of abundant near-neutral seawater resources for hydrogen production faces significant challenges due to insufficient catalyst activity and salt toxicity. Herein, we demonstrate a novel dendritic urchin-like MoC/MoS2 heterojunction in-situ formed on carbon cloth (CC@MoC/MoS2-H) through a combination of hydrothermal and high-temperature annealing processes. This unique dendritic urchin-like structure consists of numerous nanorods on carbon cloth, which enhances the catalytic active sites and provides space for efficient bubble release. The resulting CC@MoC/MoS2-H exhibits superior catalytic performance, with an overpotential of 91 mV and 136 mV at the current density of 10 mA cm−2 in the 1 M PBS electrolyte and natural seawater, respectively, surpassesing that of most non-noble metal compounds reported previously. Finite element simulations reveal that the urchin-like structure has significantly higher bubble release capacity compared to the randomly stacked structure. Additionally, the urchin-like structure demonstrates substantially greater current density retention under electrolytic conditions designed to simulate salt accumulation, in comparison to the small-size structure. Furthermore, the average H2 production efficiency of 78,493 μmol h−1 g−1 was evaluated for three consecutive hours using commercial solar panels rated at 2 V on a large-scale electrode assembly from seawater, which is comparable to the present photocatalytic hydrogen production efficiency. This work opens new avenues for the development of catalytic structures compatible with seawater.

Single-Atom Mn Catalysts via Integration with Mn Sub Nano-Clusters Synergistically Enhance Oxygen Reduction Reaction.

Integrating single atoms and clusters into one system represents a novel strategy for achieving the desired catalytic performance. In comparison to single-atom catalysts, catalysts combining single atoms and clusters harness the advantages of both, thus displaying greater potential. Nevertheless, constructing single-atom-cluster systems remains challenging, and the fundamental mechanism for enhancing catalytic activity remains elusive. In this study, a directly confined preparation of a 3D hollow sea urchin-like carbon structure (MnSA/MnAC-SSCNR) is developed. Mn single atoms synergistically interact with Mn clusters, optimizing and reducing energy barriers in the reaction pathway, thus enhancing reaction kinetics. Consequently, in contrast to Mn single-atom catalysts (MnSA-SSCNR), MnSA/MnAC-SSCNR exhibits significantly improved oxygen reduction activity, with a half-wave potential (E1/2) of 0.90V in 0.1m KOH, surpassing that of MnSA-SSCNR and Pt/C. This work demonstrates a strategy of remote synergy between heterogeneous single atoms and clusters, which not only contributes to electrocatalytic reactions but also holds potential for reactions involving more complex products.