Confinement Strategy Research Articles

Boosting Photocatalytic Hydrogen Evolution by a Light Coupling and Charge Carrier Confinement Strategy

AbstractHigh‐performance photocatalysis requires efficient light absorption and low charge carrier recombination rates. Herein, a light coupling and charge carrier confinement strategy is demonstrated to simultaneously enhance the light absorption efficiency and suppress the charge carrier recombination for high‐performance photocatalysis. The strategy is achieved by the delicate incorporation of catalysts into a dual‐core‐shell structure (e.g., CdS@SiO2@NaYF4:Yb/Tm), in which CdS (catalyst), SiO2, and NaYF4:Yb/Tm serve as shell, outer core, and inner core, respectively. Interestingly, the absorbed light can be confined within the CdS layer through multiple reflections between the CdS and SiO2 interfaces, achieving light confinement. This confinement endows a longer light residence time, enhanced light reabsorption and reutilization efficacy, and a higher concentration of photogenerated charge carriers per unit of time. Moreover, the insulating SiO2 can confine the photogenerated charge carriers within CdS layer, thus shortening their diffusion length for reduced recombination rates. Notably, when employed as the photocatalyst, this dual‐core‐shell structure showed a superb photocatalytic hydrogen evolution rate up to 74.67 mmol g−1 h−1, which is 11 times higher than that of pristine CdS. This work provides a new strategy for the design and synthesis of high‐performance photocatalysts.

Single-Atomic Mn–N–C Catalyst with Hierarchical Pores for Anion Exchange Membrane Fuel Cells: A Mn Confinement Strategy

Single-Atomic Mn–N–C Catalyst with Hierarchical Pores for Anion Exchange Membrane Fuel Cells: A Mn Confinement Strategy

Ultrathin Self-Healing Nanofibrous Membrane with a Hierarchical Confined Structure for Biomimetic Epidermal Electrodes.

Integrating self-healing capabilities into epidermal electrodes is crucial to improving their reliability and longevity. Self-healing nanofibrous materials are considered an ideal candidate for constructing ultrathin, long-lasting wearable epidermal electrodes due to their lightweight and high breathability. However, due to the strong interaction between fibers, self-healing nanofiber membranes cannot exist stably. Therefore, the development of self-healing and breathable nanofibrous epidermal electrodes still remains a major challenge. Here, a hierarchical confinement strategy that combines molecular and spatial confinement to overcome supramolecular hydrogen bonding between self-healing nanofibers is reported, and an ultrathin self-healing nanofibrous epidermal electrode with a neural net-like structure is developed. It can achieve real-time monitoring of electrophysiological signals through long-term conformal attachment to skin or plants and has no adverse effects on skin health or plant growth. Given the almost imperceptible nature of epidermal electrodes to users and plants, it lays the foundation for the development of biocompatible, self-healing, wearable, flexible electronics.

Sulfur Distribution Analysis in Lithium−Sulfur Cathode via Confined Inverse Vulcanization in Carbon Frameworks

AbstractLithium–Sulfur (Li–S) batteries are promising energy storage devices due to their high theoretical energy density. However, challenges such as the shuttling effect and volume expansion have significantly hindered their cycle life and capacity retention. Furthermore, the complex kinetic pathways in Li–S batteries call for advanced characterization techniques to unravel underlying mechanisms. In this study, a hollow porous carbon (HPC) is used as a microreactor, where inverse vulcanization occurs between 1,3‐diisopropylbenzene (DIB) and sulfur (S8), resulting in the creation of three‐dimensionally interconnected and well‐distributed S‐DIB in carbon frameworks. As a result, the dual confinement strategy imparts Li–S coin cells with remarkable cycling stability and capacity retention, exhibiting an impressive capacity of 866 mAh g−1 when returning to 0.1 C after 100 cycles of rate capability tests. Particularly, the Energy‐selective Backscattered (EsB) assisted Scanning Electron Microscope (SEM) technique as a novel approach is introduced to distinguish different lengths of polysulfides. Their distribution is visualized in the cross‐section view of the electrode in a micrometer range. These EsB images provide concrete indications of the sulfur evolution process and explain the capacity degradation during cycling.

Spatial confinement strategy modulated by kinetic diameters of gaseous molecules for sodium storage

Constructing closed pore structures is essential for improving the plateau capacity of high-capacity hard carbon (HC) anodes for sodium-ion batteries. However, the absence of a straightforward and efficient strategy for constructing closed pores has hindered the advancement of high-capacity HC anodes. Here, we have developed a spatial confinement strategy for constructing closed pore structures using pyrolytic carbon (PC) as substrate and pyrolysis gas as the carbon source for chemical vapor deposition. The deposition of pyrolysis gas effectively tightens the pore entrance, thereby preventing electrolyte infiltration and transforming the open pores in the PC into highly efficient sites for sodium storage. The obtained optimal anodes demonstrate a remarkable specific capacity of 324.6 mAh g-1. More importantly, we calculate the kinetic diameters of the carbon source molecules from their iso-electron density surfaces and correlate them with the mechanism of closed pore formation, which will effectively guide the fabrication of closed pores for sodium storage.

Interfacial space confinement engineering toward ultrastable all-climate aqueous zinc ion batteries

The interfacial instability, particularly uncontrollable Zn nucleation and deposition, significantly impeding the commercialization of aqueous zinc ion batteries (ZIBs). Herein, we propose an interfacial space confinement strategy to enable the dendrite-free anode, specifically through constructing a zincophilic buffer layer based on hollow Sn@C. The porous Sn@C contributes to modify the electrical double layer structure, which greatly alleviates the concentration polarization during high-rate plating. In-situ experimental results demonstrate the inhibited H2O-mediated parasitic side reactions and the absence of dendrite deposition morphology. Based on the improved thermodynamics and kinetics, zincophilic buffer layers can deliver low nucleation overpotential (20 mV), ultrastable cycle life (> 5000 h), and excellent zinc utilization rate (62.4%). Importantly, the full batteries with zincophilic buffer layer exhibit excellent electrochemical stability over -40 to 70 °C, pushing forward the construction of advanced all-climate ZIBs.

Three-dimensional MOFs confined Anderson-type POMs clusters—Templated fabrication of porous Co-NiMo/Cr2O3 catalyst with superior NH3-SCR catalytic activity

Fabricating ecofriendly and high-performance NOx reduction catalysts is significant but challenging. This study introduces an innovative approach for creating homogeneous and porous Co-NiMo/Cr2O3 composites by employing a POMs@MOFs (POMs = polyoxometalates, MOFs = metal organic frameworks) core − shell template as a precursor and subsequent high-temperature treatment, in which the Anderson-type POMs are confined within the MIL-101 MOFs as secondary building units. The well-organized architecture of NiMo6@MIL-101 made it possible to provide a widely dispersed metal source and later transform into defect-rich catalyst. This confinement strategy allows the prepared Co-NiMo/Cr2O3 catalysts to be uniformly dispersed without aggregation and exposes abundant active sites. It also triggers more electron transfer, producing a strong synergistic effect that results in an increase in specific surface area, Olatt/Otol ratio and the number of acidic sites. Boosted by synergistically multidoping effect, the as-prepared Co-NiMo/Cr2O3 catalyst exhibits superior activity in NOx reduction (95 %, 150 °C), which is 3 times that of Cr2O3 derived from pure MOFs under the same condition. This work may shed the light on the design and fabrication of multifunctional nanoporous metal oxide composites materials and inspire the application of polyoxometalates in NOx removal processes.

Anion Doping and Dual-Carbon Confinement Strategies to Synergistically Boost the Sodium Storage Performance of Cobalt-Based Sulfides.

Cobalt-based sulfides (CSs) are generally regarded as potentially valuable anode materials for sodium-ion batteries (SIBs) due to their excellent theoretical capacity and natural abundance. Nevertheless, their slow reaction kinetics and poor structural stability restrict the practical application of the materials. In this study, the dual-carbon-confined Se-CoS2@NC@C hollow nanocubes with anion doping are synthesized using ZIF-67 as the substrate by resorcin-formaldehyde (RF) encapsulation and subsequent carbonization and sulfurization/selenization. RF- and ZIF-67-derived dual-carbon skeleton hollow structures with a robust carbon skeleton and abundant internal space minimize cyclic stress, mitigate volume changes and maintain the structural integrity of the material. More importantly, Se doping increases the lattice spacing of CoS2, weakens the strength of Co-S bonds, and modulates the electronic structure around Co atoms, thereby optimizing the adsorption energy of the material. As a result, the hollow nanocubes of Se-CoS2@NC@C demonstrates excellent electrochemical performance as the anode for SIBs, delivering a high reversible capacity of 549.4 mAh g-1 at 0.5 A g-1 after 100 cycles and a superb rate performance (541.1 mAh g-1 at 0.2 A g-1, and 393.3 mAh g-1 at 5 A g-1). This study proposes a neoteric strategy for synthesizing advanced anodes for SIBs through the synergy of anion doping engineering and dual-carbon confinement strategy.

Carbon and MXene Dual Confinement and Dense Structural Engineering Toward Construct High Performance Micron‐SiOx Anode for Li‐Ion Batteries

AbstractThe intrinsic low conductivity, low tap density, and huge volume expansion during lithium storage severely restrict the practicality of micron‐silicon suboxide (m‐SiOx). Here, a carbon and MXene dual confinement and dense structural engineering strategy is proposed to construct m‐SiOx composites (m‐SiOx@C/MXene) through in situ carbon coating and electrostatic self‐assembly process. This integrated structural achieves a conductivity of 157 S cm−1 for m‐SiOx@C/MXene, which is 7 and 2 orders of magnitude higher than m‐SiOx (5.3 × 10−5 S cm−1) and m‐SiOx@C (2.9 S cm−1), respectively. The tap density of m‐SiOx@C/MXene reaches 1.35 g cm−3, significantly greater than that of m‐SiOx (0.82 g cm−3) and m‐SiOx@C (0.75 g cm−3). The 29% volume expansion of m‐SiOx@C/MXene during lithium storage is much lower than the 228% and 162% of m‐SiOx and m‐SiOx@C. The synergistic effect of the above advantages enables m‐SiOx@C/MXene to exhibit excellent rate performance and cycle stability. When assembled into a full cell with the LiFePO4 (LFP) cathode, it features high capacity retention and energy density of 99.1% and 380 Wh kg−1 after 100 cycles at 0.2 C. This work provides new reference for the stable structural design of m‐SiOx or other materials with huge volume expansion during energy storage.

Constructing CoP/Ni2P Heterostructure Confined Ru Sub-Nanoclusters for Enhanced Water Splitting in Wide pH Conditions.

Developing efficient electrocatalysts for water splitting is of great significance for realizing sustainable energy conversion. In this work, Ru sub-nanoclusters anchored on cobalt-nickel bimetallic phosphides (Ru-CoP/Ni2P) are constructed by an interfacial confinement strategy. Remarkably, Ru-CoP/Ni2P with low noble metal loading (33.1µgcm-2) shows superior activity for hydrogen evolution reaction (HER) in all pH values, whose turnover frequency (TOF) is 8.7, 15.3, and 124.7 times higher than that of Pt/C in acidic, alkaline, and neutral conditions, respectively. Meanwhile, it only requires the overpotential of 171 mV@10mAcm-2 for oxygen evolution reaction (OER) and corresponding TOF is 20.3 times higher than that of RuO2. More importantly, the Ru-CoP/Ni2P||Ru-CoP/Ni2P displays superior mass activity of 4017mAmgnoble metal -1 at 2.0V in flowing alkaline water electrolyzer, which is 105.1 times higher than that of Pt/C||IrO2. In situ Raman spectroscopy demonstrates that the Ru sites in Ru-CoP/Ni2P play a key role for water splitting and follow the adsorption evolution mechanism toward OER. Further mechanism studies disclose the confined Ru atom contributes to the desorption of H2 during HER and the formation of O-O bond during OER, leading to fast reaction kinetics. This study emphasizes the importance of interface confinement for enhancing electrocatalytic activity.

Catalytic Enantioselective Macrocyclization for the Synthesis of Planar‐Chiral Cyclophanes: Recent Updates

The planar chirality of macrocycles is a fascinating research topic. Locking the configurational flip between the benzene ring and macrocycle leads to planar chirality, which can significantly enhance the biological activity of cyclophanes. Planar‐chiral cyclophanes are widely used in pharmaceuticals, chiral catalysts, and functional materials. However, accessing planar‐chiral cyclophanes via asymmetric catalysis has remained challenging. Among the various strategies, asymmetric macrocyclization provides a powerful tool for accessing planar‐chiral cyclophanes. This method allows for control of the planar chirality when constructing the macrocycle and greatly improves the efficiency. There are three types of macrocyclization reactions: transition metal‐catalyzed, organocatalyzed, and biocatalyzed. In addition, the chiral confinement strategy breaks through conservative synthetic approaches. This review summarizes these achievements, aiming to highlight the catalytic asymmetric synthesis of cyclophanes and inspire interested researchers.

Synthesis of nitrogen-rich porous carbon via a molecular confinement strategy for activating peroxymonosulfate in bisphenol A degradation: Role of singlet oxygen and electron transfer process

Nitrogen-doped porous carbon (NPC) catalysts show potential for activating peroxymonosulfate (PMS) to treat water pollution. However, nitrogen (N) experiences significant loss during pyrolysis, posing challenges for synthesizing N-rich carbon catalysts. This study innovatively proposed a molecular confinement strategy using the C−S−C bond formed between graphitic carbon nitride and mercaptan. Under this confinement, we successfully synthesized NPC-15 with a high N content (21.4 at%), surpassing most catalysts reported in the literature. NPC-15/PMS system showed excellent performance in degrading bisphenol A (BPA), achieving complete degradation within 3 min (kobs = 1.771 min−1), surpassing the effectiveness of most previously reported catalysts. The NPC-15/PMS system exhibited excellent performance and stability under various conditions, reducing BPA toxicity to ecological and human embryonic kidney cells. Moreover, it maintained stability during long-term continuous operation in a fixed-bed reactor, showing promise for practical applications. Through experiments and theoretical calculations, the mechanism of NPC-15 activating PMS was comprehensively investigated. The NPC/PMS system operated via a dual non-radical pathway involving singlet oxygen and electron transfer process induced by pyridinic N and graphitic N dual active sites. Pyridinic N promoted the generation of 1O2, while graphitic N supported the electron transfer process. This study introduced a new strategy for the preparation of N-rich carbon catalysts and proposed a novel method for the removal of emerging pollutants in water.

CONTRASTING A MODEL MODELLING OF PERCEPTION COVID-19

Mitigation policies, as their objective is the informative control of the pandemic in terms of its effects on public health, stand out because they consider risks as inherent to social communication. In this sense, the objective of this work was modelling the social perception of the risks associated with the SARS CoV-2 and Covid-19 pandemics. Axes, trajectories and relationships between categories were established that explain and anticipate the effects of confinement and social distancing strategies, alluding to the extension of the study in confinement and high-risk settings such as hospitals, the adoption of self-care and adherence to treatment. from the impact of the pandemic on the parties involved.

A Charge Confinement Strategy for Boosting Interfacial Space Charge Storage in Manganese Ferrites Enabled by Highly Polarized Fluorinated‐Interfacial Layer for High‐Energy‐Density and Ultrafast Rechargeable Lithium‐Ion Batteries

A Charge Confinement Strategy for Boosting Interfacial Space Charge Storage in Manganese Ferrites Enabled by Highly Polarized Fluorinated‐Interfacial Layer for High‐Energy‐Density and Ultrafast Rechargeable Lithium‐Ion Batteries

Alleviated volume changes of germanium anode via facile chemical confinement strategy

Germanium (Ge) anode shows great promise in overcoming unsatisfied capacity and dendrite formation concerns facing conventional graphite anodes in next generation lithium ion batteries. However, volume changes during repeated alloying and de-alloying cycles seriously impair structural stability and cycle lifespan. In this work, a facile chemical confinement strategy has been firstly proposed to alleviate volume changes of Ge anode. Benefited from strong binding interaction between Ge and ZnS, discrete Ge nanoparticle can be successfully encapsulated within thin protective ZnS shell and N-doped carbon layer (Ge-ZnS@N-C) after two-step carbonization and sulfurization of polydopamine-coating Zn2GeO4 nanorod precursors. In contrast, bulk Ge aggregates and hollow N-doped carbon nanotubes can be formed without chemical confinement of ZnS. The as-prepared Ge-ZnS@N-C sample displays multifold structural merits, including nanosized Ge particles with highly electrochemical activity, sufficient pores and functional groups that facilitate ion diffusion. Besides, protective ZnS shell and N-doped carbon layer can suppress volume changes of Ge nanoparticles and guarantee high electrode reversibility, demonstrated by a series of in-situ and ex-situ experiments. The as-synthesized Ge-ZnS@N-C anodes exhibit stable long-cycle performance (1389.7 mAh/g after 450 cycles at a current density of 0.5 A/g) and excellent rate performance (548.5 and 397.8 mAh/g at 5.0 and 8.0 A/g, respectively).

Synthetic Chemistry and Microelectrode Arrays for Point of Care Diagnostics

Molecular diagnostics typically require a molecular interaction that identifies a specific target, a device that detects, quantifies, and records that interaction, and an interface between those two elements. Each feature is critical for the success of the device. Yet while the first two are matters of intense interest an research, the surface itself is often ignored. This is problematic because it provides the platform for the whole "experiment". For a "point-of-care" diagnostic, the surface on the device must be stable both in terms of chemistry and time while still allowing the signal from the molecular interaction to be sensed and recorded.With this in mind, we have been focusing on the use of diblock copolymers as molecular surfaces for the construction of "point-of-care" diagnostics. We have developed a toolbox of chemical reactions that can be used site-selectively on such surfaces, and we have recently demonstrated that the approach taken is compatible with the use of DNA-aptamers to do multiplex sensing on a high density microelectrode array using a surface that is stable for a year. We have also illustrated how the quality of the signaling study conducted on an array is dependent on optimization of the chemical reaction.But exactly how good are the chemical reactions employed on the arrays to build a surface in a site-selective manner? One can tell with the use of fluorescence based studies that reactions happen where you want then to happen, but are there background reactions that can be problematic for a multiplex sensing experiment, do the reactions happen in high yield, and how much of an expensive, difficult to obtain biological reagent might be lost due to the confinement strategy? Are some reactions better than others in this regard? In short, if we are to optimize the surfaces constructed on a diagnostic device, then we need not only have tools in place for conducting synthetic chemistry on the device, but also the tools in place necessary to analyze those reactions. Understanding the chemistry that can and/or does occur at any electrode in a high density array requires more than looking at pretty pictures of fluorescent spots. In the talk to be given, we will utilize a combination of a "Kenner-safety-catch" linker strategy and molecular biology techniques to answer key questions about the synthetic chemistry used to construct the DNA-aptamer based multiplex sensor mentioned above.

Regulating Fe-spin state by doping P heteroatom in Fe-N-C catalyst derived from colloidal nanoparticles encapsulated ZIF-8 to boost oxygen reduction activity

Over the past decades, Fe-N-C carbon materials have been considered as one of the most ideal alternatives to the noble metal catalysts (e.g. Pt/C) for the sluggish oxygen reduction reaction (ORR) in zinc-air batteries and fuel cells. In this research, ZIF-8 cage encapsulation confinement strategy coupled with post P-doping has been employed to design porous P, N and Fe co-doped carbon (FeNC-P) for efficient oxygen reduction reaction (ORR). The zero-field cooling (ZFC) temperature-dependent magnetic susceptibility measurement revealed that incorporation of P in the Fe-N-C catalysts can induce the transition of spin polarization configuration, which promotes the desorption of *OH in the crucial step of the ORR reaction process. The best-performing FeNC-P catalyst displays a 1.00 V (vs RHE) of Eonset (onset potential) and a 0.90 V (vs RHE) of E1/2 (half-wave potential) in an alkaline solution, which exceeds the benchmark Pt/C catalyst. Moreover, it also delivers a high power density of 130 mW·cm−2 in the self-made zinc-air battery, surpassing the benchmark Pt/C catalyst (90 mW·cm−2).

Size Confinement Strategy Effect Enables Advanced Aqueous Zinc–Iodine Batteries

AbstractAqueous Zn–I2 batteries have considerable potential owing to their environmental friendliness and high safety. However, the slow iodine conversion kinetics and shuttle effect prevent their practical applicability. In this study, a series of Zn‐MOF‐74 rods with controllable diameters of 40–500 nm are facilely prepared, denoted as P1–P5. A size confinement strategy effect of Zn‐MOF‐74 derived porous carbon as iodine hosts is proposed to suppress the formation of undesirable iodine species, such as I3− and I5−. Moreover, the graphitization degree of porous carbon samples, including P2‐900, P2‐1000, and P2‐1100, play a critical effect on the iodine conversion kinetics. The P2‐1000 sample possesses a high conductive skeleton and abundant mesopores, which improve the adsorption ability toward iodine species. The electrochemical tests and the in situ technology reveal the size confinement strategy effect and the conversion mechanism of iodine. As a result, the I2@P2‐1000 cathode exhibits a superior discharge capacity of 179.9 mA h g−1 at 100 mA g−1 and exceptional long‐term cycle ability after 5000 cycles. Furthermore, the soft batteries and the flexible quasi‐solid‐state batteries are capable of powering devices, promising to exhibit tremendous adaptability and realize flexible electronic devices in various scenarios.

Improvement of mechanical properties of TATB-based polymer bonded explosive by surface confinement and interfacial strengthening

Improvement of mechanical properties of 1, 3, 5-triamino-2, 4, 6-trintrobenzene (TATB) based polymer bonded explosives (PBX) is extremely desirable but still a big challenge. In this study, surface confinement and interfacial strengthening strategies were used to enhance the mechanical properties of TATB-based PBX. Firstly, TATB crystals were coated with a polydopamine (PDA) layer. Subsequently, various amounts (0.3, 0.5 and 0.8 wt%) of neutral polymeric bonding agent (NPBA) were grafted onto the PDA layer using 2,4-toluene diisocyanate as a molecular bridge. The results showed that the modified TATB composites-based PBX exhibited improved mechanical strength, as well as creep resistance properties compared to the raw TATB-based PBX. The modified TATB composites-based PBX with 0.5 wt% NPBA grafting content exhibited the highest mechanical strength and creep resistance due to the surface confinement effect of the rigid crosslinked PDA layer and interfacial strengthening effect of the NPBA layer. Present work might provide a promising strategy for synergistically improving the mechanical properties of TATB-based PBX.

Confinement and heating promoted RTP of flumequine, oxolinic acid and levofloxacin on papers for their detection and discrimination

Developing simple assays to identify and discriminate quinolones are highly desired for food safety, which remain a great challenge due to the interferences from food matrices and the minor variation on the molecular structure of massive quinolones. We proposed a room-temperature phosphorescence (RTP) assay for the quantitative detection and discrimination of quinolones, aided by a confinement and heating strategy. Quinolones were loaded into the porous framework of paper, which provided confinement effects on the molecular motions of quinolones. The heating process further removed the solvents, eliminating their quenching effects on excitons. These synergistic effects improved the RTP intensity and emission lifetime by 1144-fold and from nanoseconds to seconds, respectively. Three types of quinolones were quantitatively detected and discriminated through pattern recognition methods. The proposed assay showed excellent detection performance in complicated meat samples, aided by the delayed signal collecting of RTP. The reported results provided a clue to modulate the RTP properties of organic molecules, showing great potential for application prospect in food safety analysis, environmental and healthy monitoring.