Strong Interfacial Interaction Research Articles

Water Self‐Dissociation is Insensitive to Nanoscale Environments

AbstractNanoconfinement effects on water dissociation and reactivity remain controversial, despite their importance to understand the aqueous chemistry at interfaces, pores, or aerosols. The pKw in confined environments has been assessed from experiments and simulations in a few specific cases, leading to dissimilar conclusions. Here, with the use of carefully designed ab initio simulations, we demonstrate that the energetics of bulk water dissociation is conserved intact to unexpectedly small length‐scales, down to aggregates of only a dozen molecules or pores of widths below 2 nm. The reason is that most of the free‐energy involved in water autoionization comes from breaking the O−H covalent bond, which has a comparable barrier in the bulk liquid, in a small droplet of nanometer size, or in a nanopore in the absence of strong interfacial interactions. Thus, dissociation free‐energy profiles in nanoscopic aggregates or in 2D slabs of 1 nm width reproduce the behavior corresponding to the bulk liquid, regardless of whether the corresponding nanophase is delimited by a solid or a gas interface. The present work provides a definite and fundamental description of the mechanism and thermodynamics of water dissociation at different scales with broader implications on reactivity and self‐ionization at the air‐liquid interface.

Water Self-Dissociation is Insensitive to Nanoscale Environments.

Nanoconfinement effects on water dissociation and reactivity remain controversial, despite their importance to understand the aqueous chemistry at interfaces, pores, or aerosols. The pKw in confined environments has been assessed from experiments and simulations in a few specific cases, leading to dissimilar conclusions. Here, with the use of carefully designed ab initio simulations, we demonstrate that the energetics of bulk water dissociation is conserved intact to unexpectedly small length-scales, down to aggregates of only a dozen molecules or pores of widths below 2 nm. The reason is that most of the free-energy involved in water autoionization comes from breaking the O-H covalent bond, which has a comparable barrier in the bulk liquid, in a small droplet of nanometer size, or in a nanopore in the absence of strong interfacial interactions. Thus, dissociation free-energy profiles in nanoscopic aggregates or in 2D slabs of 1 nm width reproduce the behavior corresponding to the bulk liquid, regardless of whether the corresponding nanophase is delimited by a solid or a gas interface. The present work provides a definite and fundamental description of the mechanism and thermodynamics of water dissociation at different scales with broader implications on reactivity and self-ionization at the air-liquid interface.

Ultralight, Heat-Insulated, and Tough PVA Hydrogel Hybridized with SiO2 @cellulose Nanoclaws Aerogel via the Synergy of Hydrophilic and Hydrophobic Interfacial Interactions.

Lightweight porous hydrogels provide a worldwide scope for functional soft mateirals. However, most porous hydrogels have weak mechanical strength, high density (>1g cm-3 ), and high heat absorption due to weak interfacial interactions and high solvent fill rates, which severely limit their application in wearable soft-electronic devices. Herein, an effective hybrid hydrogel-aerogel strategy to assemble ultralight, heat-insulated, and tough polyvinyl alcohol (PVA)/SiO2 @cellulose nanoclaws (CNCWs) hydrogels (PSCG) via strong interfacial interactions with hydrogen bonding and hydrophobic interaction is demonstrated. The resultant PSCG has an interesting hierarchical porous structure from bubble template (≈100 µm), PVA hydrogels networks introduced by ice crystals (≈10 µm), and hybrid SiO2 aerogels (<50nm), respectively. PSCG shows unprecedented low density (0.27g cm-3 ), high tensile strength (1.6MPa) & compressive strength (1.5MPa), excellent heat-insulated ability, and strain-sensitive conductivity. This lightweight porous and tough hydrogel with an ingenious design provides a new way for wearable soft-electronic devices.

Interfacial Electronic Interaction in In2O3/Poly(3,4-ethylenedioxythiophene)-Modified Carbon Heterostructures for Enhanced Electroreduction of CO2 to Formate.

Formate, as an important chemical raw material, is considered to be one of the most promising products for industrialization among CO2 electroreduction reaction (CO2RR) products, but it still suffers from poor selectivity and a low formation rate at a high current density on account of the competitory hydrogen evolution reaction. Herein, the heterogeneous nanostructure was constructed by anchoring In2O3 nanoparticles on poly(3,4-ethylenedioxythiophene) (PEDOT)-modified carbon black (In2O3/PC), in which the PEDOT polymer interface layer could immobilize In2O3 nanoparticles and obtain a notable reduction in electron transfer resistance among the In2O3 particles, showing a 27% increase in the total electron transfer rate. The optimized In2O3/PC with rich heterogeneous interfaces selectively reduced CO2 to formate with a high FE of 95.4% and a current density of 251.4 mA cm-2 under -1.18 V vs RHE. Also, the formate production rate for In2O3/PC was up to 7025.1 μmol h-1 cm-2, surpassing most previously reported CO2RR catalysts. The in situ XRD results revealed that In2O3 particles were reduced to metallic indium (In) as catalytic active sites during CO2RR. DFT calculations verified that a strong interface interaction between In sites and PC induced electron transfer from In sites to PC, which could optimize the charge distribution of active sites, accelerate electron transfer, and elevate the p-band center of In sites toward the Fermi level, thereby lowering the adsorption energy of *OCHO intermediates for CO2 conversion to formate.

Influence of Silane-Post Treatment on Sodium Dodecylbenzene Sulfonate:Zinc Sulfate Pre-Treated Mild Steel and Its Effect on Adhesion Properties of Organic Coating

This paper describes the effect of post-treated mild steel substrates containing a sodium dodecyl benzenesulfonate:zinc sulfate (SDBS:ZnSO4) inhibitor mixture as the first layer pre-treatment with 3-glycidoxypropyltrimethoxysilane (3- GPS) on the overall corrosion protection and adhesion of an epoxy protective coating. The protective layer was characterized by linear polarisation resistance measurement (LPR), electrochemical impedance spectroscopy (EIS), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) tests, while the adhesion of the epoxy coating to this pre-treated mild steel was evaluated by a pull-off test. The silane-post treated SDBS:ZnSO4 mild steel showed excellent corrosion resistance in sodium chloride solution with good adhesion to the epoxy coating. However, the adhesion was highly dependent on the silane post-treatment methods. The increase in corrosion resistance and adhesion is due to increased surface passivation and the formation of strong interfacial interactions.

Redox kinetics promoted by flower-like La2CoMnO6 @NiCo2O4 heterojunctions for high-performance supercapacitors

The double perovskite oxide La2CoMnO6 (LCMO) is suitable for supercapacitor applications owing to its fast oxygen anion conduction and strong electron conductivity. However, the poor electron transfer of spinel oxide electrode materials weakens the intensity of surface redox reactions, thereby hindering the further improvement of energy density of the supercapacitors. In this study, flower-like heterogeneous La2CoMnO6 @NiCo2O4 materials were in-situ grown on a nickel foam (LCMO@NCO/Ni) via interface engineering and morphological engineering for the first time. The as-constructed heterogeneous materials benefit from the high electron conductivity of LCMO for the rapid transfer of electrons in NiCo2O4 (NCO), resulting in increased surface redox reaction rates. Interestingly, these successfully constructed heterogeneous LCMO and NCO structures act as electron donor and acceptor, respectively. Such a system promotes the increase in the electron cloud density around NCO, leading to an enhanced intensity of the redox reactions. The unique nanoflower-like structure and strong interfacial interaction of the developed heterogeneous LCMO@NCO/Ni material result in an electrode material with excellent supercapacitor performance with a high specific capacitance of 598 F·g−1 at a current density of 1 A·g−1. The asymmetric supercapacitor assembled with activated carbon and as-prepared material possesses a high energy density of 39.9 Wh·kg−1 at 1600 W·kg−1, proving suitable for practical applications. Overall, the proposed synthesis strategy is promising for the fabrication of novel heterogeneous electrode materials for supercapacitors with improved energy density.

Modulating the Conduction Band of MOFs by Introducing Tiny TiO2 Nanoparticles for Enhanced Photocatalytic Performance: Importance of the Loading Position.

The preparation of TiO2 and metal-organic framework (MOF) into composite photocatalysts has been proven to be a mature and effective strategy to achieve stronger catalytic activity. In this work, we focus on exploring the significant effects and mechanisms of the relative positions of decorated titanium oxide nanoparticles and MOFs on the final catalytic activity. We first used a simple in situ method to encapsulate tiny TiO2 nanoparticles into a Zr-MOF (PCN-222), where Zr-Ti bonds were created at the interface of the two components. Thanks to the strong interfacial interaction forces, band bending occurred in TiO2@PCN-222 and a more negative conduction band (Δ = 0.26 V) with better electron transport properties was obtained. The results of photocatalytic CO2 reduction experiments under visible light showed a 78% increase (142 μmol g-1 h-1) in the production rate of HCOO-. Surprisingly, the loading of TiO2 nanoparticles on the MOF surface (TiO2@PCN-222) resulted in a significant decrease of 56% in the catalyst yield activity due to poor adsorption and electron transfer properties. This work demonstrates the possibility of tuning the band structure and catalytic activity of MOFs with the help of changing the position of the dopant and shows the importance of the rational design of MOF-based composites.

0D-2D nanohybrids based on binary transitional metal oxide decorated boron nitride enabled epoxy resin efficient flame retardant coupled with enhanced thermal conductivity at ultra-low additions

Epoxy resin (EP) possesses standout traits in adhesion, electrical insulation, as well as mechanical properties, thus it is frequently concerned in the field of electronic packaging. However, EP has shortcomings of poor flame retardancy and thermal conductivity, and it is easy to induce thermal runaway in long-term service. In this work, 0D-2D nanohybrids (BN@CoFeOx) were obtained through a facile coprecipitation-thermal oxidation method, where cobalt-iron metal oxides as decorations were in situ generated on the surface of boron nitride (BN) as the substrate. Then, EP/BN@CoFeOx nanocomposites were prepared by physical blending of BN@CoFeOx and EP, pouring and curing. BN@CoFeOx nanohybrids fulfilled homogeneous dispersion in EP and strong interfacial interactions with the EP matrix. Besides, BN@CoFeOx nanohybrids imparted EP with high flame-retardant efficiency and exceeding smoke suppression properties at low additions of only 2 wt%, reflected in a 44.7%, 42.7%, 54.8%, and 56.2% decrease of the peak heat release rate (pHRR), total heat release rate (THR), peak smoke production rate (pSPR), and total smoke production (TSP) values, respectively. Furthermore, the limiting oxygen index (LOI) value increased from 24.2% of EP to 34.3%, and the vertical combustion test (UL-94) results reached a V0 rating. Meanwhile, the introduction of BN@CoFeOx nanohybrids adjusted for the formation of highly graphitized carbon layers, and boosted the thermal stability of EP. When the addition of BN@CoFeOx nanohybrids was 0.5 wt%, the peak mass loss rate (Rmax) of EP/BN@CoFeOx nanocomposites dropped by 33.6%. In addition, on account of the phonon transfer within and between nanohybrids, combined with the thermal conduction path formed by nanohybrids, BN@CoFeOx accomplished the thermal conductivity enhancement of EP. Hence, the newly designed and prepared EP/BN@CoFeOx nanocomposites provide the possibility to dissipate heat accumulation and promote the flame-retardant performance of electronic products, and consequently reduce the occurrence of thermal runaway.

Skinless Polyphenylene Sulfide Foam with Enhanced Thermal Insulation Properties Fabricated by Constructing Aligned Gas Barrier Layers for Surface-Constrained sc-CO2 Foaming.

A solid skin layer inevitably forms on the foam surface for supercritical carbon dioxide (sc-CO2) foaming technology, leading to deterioration of some inherent properties of polymeric foams. In this work, skinless polyphenylene sulfide (PPS) foam was fabricated with a surface-constrained sc-CO2 foaming method by innovatively constructing aligned epoxy resin/ferromagnetic graphene oxide composites (EP/GO@Fe3O4) as a CO2 barrier layer under a magnetic field. Introduction of GO@Fe3O4 and its ordered alignment led to an obvious decrease in the CO2 permeability coefficient of the barrier layer, a significant increase of the CO2 concentration in the PPS matrix, and a decrease of desorption diffusivity in the depressurization stage, suggesting that the composite layers effectively inhibited the escape of CO2 dissolved in the matrix. Meanwhile, the strong interfacial interaction between the composite layer and the PPS matrix remarkably enhanced the heterogeneous nucleation of cells at the interface, resulting in elimination of the solid skin layer and formation of an obvious cellular structure on the foam surface. Moreover, by the alignment of GO@Fe3O4 in EP, the CO2 permeability coefficient of the barrier layer became much lower, and the cell density on the foam surface further increased with decreasing cell size, which was even higher than that of the cross section of foam, attributed to stronger heterogeneous nucleation at the interface than the homogeneous nucleation in the core region of the sample. As a result, the thermal conductivity of the skinless PPS foam reached as low as 0.0365 W/m·k, decreasing by 49.5% compared with that of regular PPS foam, showing a remarkable improvement in the thermal insulation properties of PPS foam. This work provided a novel and effective method for fabricating skinless PPS foam with enhanced thermal insulation properties.

Preparation of high‐performance and low‐rolling resistance tire tread compound based on hydrogen‐bonded self‐assembled graphene/carbon nanotube‐silica hybrid

AbstractGraphene/carbon nanotubes and silica hybrids (CTGS) with high dispersion and strong interface were prepared by hydrogen bond self‐assembly technique using green modifiers Tween‐80 (TW) and Oleylamine (YA) as “molecular bridge.” CTGS was added into natural rubber (NR) as an effective functional filler to prepare high‐performance, low‐rolling resistance, and antistatic tire tread. In the vulcanization process of NR filled with CTGS (CTGS/NR), CTGS can participate in the rubber vulcanization, and co‐vulcanization is a catalyst for constructing the strong interfacial interactions between CTGS and rubber. The extreme dispersion of CTGS hybrid in NR and the strong interfacial interaction between CTGS and NR are the basis for obtaining excellent comprehensive properties of CTGS/NR composites. The results show that compared with NR filled with silica modified by triethoxysilyl propyldisulfide (ST@SiO2/NR), NR filled with carbon nanotubes and silica hybrid (CTGS4) using YA as the molecular bridge (CTGS4/NR) has the best comprehensive performance. Its tensile strength increased from 27.41 to 30.18 MPa, increasing by 10.1%, the rolling resistance decreased from 0.098 to 0.087, decreasing by 11.2%, and the conductivity increased by three orders of magnitude (increasing from 2.321 × 10−7 S∙m−1 to 4.111 × 10−5 S∙m−1) indicating excellent electrostatic conductivity for CTGS hybrid with carbon nanotubes loading as low as 0.6 wt%. CTGS hybrid is expected to be a new functional filler for rubber, especially good for green tires with high‐performance, low‐rolling resistance, and antistatic performances.

Two-dimensional MoS2/Ti2CX2 (X = S, Se, Te) heterostructures with tunable electrical contact type

The tunable electrical contact type in van der Waals (vdW) heterostructures plays an important role in promoting the efficiency of ultrathin electronic devices. From the first-principles calculations, the electronic properties and electrical contact type of the MoS2/Ti2C heterostructure and its ramifications MoS2/Ti2CX2 (X = S, Se, Te) heterostructures are verified. The strong interfacial interaction is found in pristine MoS2/Ti2C heterostructure, resulting in the metallization of MoS2 layer. The functionalization of S, Se, and Te atoms can weaken the interfacial interaction, forming metal-semiconductor contact. The p-type Schottky contact is formed in MoS2/Ti2CS2 and MoS2/Ti2CSe2 heterostructures, while Ohmic contact is formed in MoS2/Ti2CTe2 heterostructure. The application of external electric field can efficiently modulate the contact type of MoS2/Ti2CX2 (X = Se and Te) heterostructures. The discrepancy of electron affinity of S, Se, and Te atoms leads to the different interlayer charge transfer, and thus the different electrical contact type can be realized in MoS2/Ti2CX2 (X = S, Se, Te) heterostructures. The tunable contact type makes these heterostructures become potential candidate materials for enhancing the nanoelectronic devices’ efficiency.

Indium selenide/silver phosphate hollow microsphere S-scheme heterojunctions for photocatalytic hydrogen production with simultaneous degradation of tetracycline

Designing heterojunction photocatalysts with strong interfacial interactions is an effective way to reduce the recombination of photogenerated charge carriers. Here, silver phosphate (Ag3PO4) nanoparticles are coupled with hollow flower-like indium selenide (In2Se3) microspheres by a facile Ostwald ripening and in-situ growth method, resulting in the construction of In2Se3/Ag3PO4 hollow microsphere step-scheme (S-scheme) heterojunction with a large contact interface. The flower-like In2Se3 with hollow and porous structure provides a large specific surface area and numerous active sites for photocatalytic reactions to take place. The photocatalytic activity was tested by measuring the hydrogen evolution from antibiotic wastewater, and the H2 evolution rate of In2Se3/Ag3PO4 reached 4206.4 µmol g-1h−1 under visible light, which is approximately 2.8 times greater than that of In2Se3. In addition, the amount of tetracycline (TC) degradation when it was used as a sacrificial agent is about 54.4% after 1 h. On the one hand, Se-P chemical bonds act as electron transfer channels in the S-scheme heterojunctions, which can facilitate the migration and separation of photogenerated charge carriers. On the other hand, the S-scheme heterojunctions can retain the useful holes and electrons with higher redox capacities, which is very favorable for the generation of more •OH radicals and the photocatalytic activity is greatly enhanced. This work provides an alternative design approach for photocatalysts toward hydrogen evolution in antibiotic wastewater.

Filler-induced heterogeneous nucleation of polymer crystals investigated by molecular dynamics simulations

Filler particles are known to act as nucleants for polymer crystallisation yet the connection between the filler surface properties and polymer crystallisation are not well understood. In this work, molecular dynamics simulations were used to investigate homogeneous and heterogeneous polymer nucleation and crystallisation using a generic linear bead–spring polymer model with a bond bending potential. The polymer systems were equilibrated at high temperature and then cooled at a constant rate. Without a surface present, polymers with stiff chains were found to crystallise more readily than more flexible polymers. The degree of crystallinity was estimated based on the mass fraction of straight chain segments which we equate to stem mass fraction. At a temperature Tc a sharp increase in density, radius of gyration and stem mass fraction occurred. After cooling, the systems were reheated and some systems showed hysteresis with a sharp decrease in these properties occurring upon melting at Tm>Tc. For slower heating rates, crystal growth occurred during heating from between the glass transition temperature, Tg, and Tc until just before melting at Tm. The presence of an isotropic surface was found to promote crystallisation in flexible systems that did not crystallise in the bulk, where the stem mass fraction and Tc increased with the interaction strength between the surface and the polymer beads. Changes in Tc and degree of crystallinity with cooling rate are consistent with experimental observations. This model captures polymer crystallisation phenomena and provides insight into heterogeneous nucleation, demonstrating that strong interfacial interactions promote crystallisation, thus aiding the choice or design of nucleants for control of polymer crystallisation and microstructure.

Simple construction of NiCo-LDH@FeOOH nanoflower heterostructure by chemical etching strategy for efficient oxygen evolution reaction

The large overpotential and slow kinetics of the oxygen evolution reaction (OER) on an anode seriously reduces the water splitting efficiency. Herein, the FeOOH decorated NiCo-layered double hydroxides (NiCo-LDH@FeOOH) nanoflower heterostructure electrocatalyst is synthesized using a simple one-step ZIF-67 derivation and chemical etching strategy. Owing to the unique 3D heterogeneous nanoflowers structure formed by etching, the strong interface interaction regulates the electronic structure, and combined with the synergistic effect between the three metals, the electrochemical activity of the catalyst is significantly increased. NiCo-LDH@FeOOH exhibits superior OER activity with a low overpotential of 255 mV at a current density of 50 mA cm–2 under alkaline conditions and provides long-term durability (73 h). Moreover, experiments and density functional theory calculations reveal that the Co-site synergistically promote the OER activity of the Fe site. This study sheds new light on constructing LDH-based heterogeneous composite electrocatalysts.

Robust, Fire-Retardant, and Water-Resistant Wood/Polyimide Composite Aerogels with a Hierarchical Pore Structure for Thermal Insulation.

The use of energy-saving materials is an effective strategy for decreasing energy consumption and carbon emission. Wood is a type of biomass material with a natural hierarchical structure, which results in its high thermal insulation. It has been widely used in construction. However, developing wood-based materials without flammability and dimensional instability is still a challenge. Herein, we developed a wood/polyimide composite aerogel with a well-preserved hierarchical pore structure and dense hydrogen bonds inside, resulting in its excellent chemical compatibility and strong interfacial interactions between its two components. This novel wood-based composite was fabricated by removing most hemicellulose and lignin from natural wood, followed by the fast impregnation using an 'in situ gel' process. The introduction of polyimide into delignified wood substantially improved its mechanical properties, with the compression resistance being improved by over five times. Notably, the thermal conductivity coefficient of the developed composite was approximately half that of natural wood. Furthermore, the composite exhibited excellent fire-retardancy, hydrophobicity, thermal insulation, and mechanical properties. This study provides a novel method for wood modification, which not only aids interfacial compatibility between wood and polyimide but also retains the properties of the two components. The developed composite can effectively reduce energy consumption, making it promising for practical and complex thermal insulation applications.

Enhanced Photovoltaic Property and Panchromatic Photocatalytic by Forming D‐π‐A‐Bacteriochlorin Dyads: A Computational Investigation

The photovoltaic characteristics and panchromatic photocatalysis based on monomers and bithiophene‐chlorophyll dyads is investigated. The optical properties and the electron transport capacity of the titled dyes are explicated by investigating the geometry, electronic structure, electron injection, and recombination, intramolecular charge transfer, regeneration process, dye aggregation, and light‐harvesting. The results manifest that the original 3,3′‐dithioalkyl‐2,2′‐bithiophene (SBT)‐based molecule behaves better with photovoltaic performance and an enhanced JSC and VOC. For molecular design, the designed dyads not only show the enhanced absorption range and prolonged excited lifetimes but also noticeable electron transfer ability. Moreover, the strong interfacial interaction, fast electron transfer process, long recombination distance, inhibition in dye aggregate, enhanced regenerative interaction energy are elucidated, which is beneficial for a better photocurrent response. However, the slight shift of the conduction band edge in dyads significantly reduces the VOC, especially for SBT‐Chl. Among dyads, SBT‐BChl exhibits outstanding photovoltaic performance of 14%. Besides, photocatalysis analysis manifests that the dyad composites behave with red‐shifted spectra, enhanced dipole moments, better interfacial interaction to ensure electron transfer, which significantly improved the photocatalytic performance of TiO2. Our study is expected to offer theoretical guidelines for further screening the promising D‐π‐A‐bacteriochlorin dyads in photoelectric functional materials.

Enhanced interfacial interaction, mechanical properties and thermal stability of basalt fiber/epoxy composites with multi-scale reinforcements

ABSTRACT In this work, epoxy (EP) resin composites with multi-scale reinforcements were prepared by hand lay-up and hot-pressing. The epoxy was reinforced with basalt fibers (BF) modified with a silane coupling agent (KH560). Carboxylated multi-walled carbon nanotubes (CNTs) were also grafted onto the surface of the modified BF using an impregnation method to achieve BF/CNTs multi-scale reinforcement. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) showed that KH560 was successfully grafted onto the BF surface. Scanning electron microscopy (SEM), indicated a better resin adhesion on the BF and thus a stronger interfacial interaction in the BF/CNTs-reinforced composite. It was observed that the mass fraction of KH560 was a significant parameter in achieving desirable CNT immobilization and mechanical properties of the composites. At an optimal mass fraction of KH560 (5%), the tensile, flexural, and interlaminar shear strength (ILSS) of the modified composite (BF-5%KH560-CNT/EP) increased by 12.5%, 20.9%, and 25.5% respectively compared with the BF-washed/EP composite due to more efficient load transfer. In addition, compared with BF-washed/EP, the decomposition onset temperature of BF-5%KH560-CNT/EP increased from 387°C to 396°C, the maximum decomposition rate temperature increased from 400°C to 408°C, and the residual weight increased by 5.8%.

Mutually supportive growth strategy to engineer a hollow biochar sphere-supported TiO2 composite with improved interfacial compatibility for efficient visible light-driven photocatalysis

Improving the interfacial compatibility between active components and support is significant and challenging. Herein, a mutually supportive growth strategy was created to engineer a Fe-Cu-doped hollow biochar sphere (HBS)-supported TiO2 (TiO2/Fe-Cu-HBS) composite with strong interfacial interaction via simultaneous growth of crystalline TiO2 and epitaxial carbonization of mechanical activation-treated starch-FeCl3-CuCl2. The TiO2/Fe-Cu-HBS composite with highly dispersed distribution and embedding of spherical TiO2 particles on the Fe-Cu-HBS shell had a narrow bandgap, favorable visible light capture and absorption capability, high separation efficiency of electron–hole pairs, and high transfer efficiency of photogenerated carriers. The superior photogenerated electron transport, high specific surface area, and enriched surface oxygen vacancies led to the generation of abundant reactive radicals on TiO2/Fe-Cu-HBS under visible light stimulation, contributing to efficient photocatalytic degradation of tetracycline hydrochloride (removal rate of 95.4% within 120 min; mineralization rate of 75.3% within 180 min), rhodamine B (removal rate of 99.2% within 100 min), and carbamazepine (removal rate of 67.5% within 120 min). Moreover, TiO2/Fe-Cu-HBS maintained high photocatalytic degradation efficiency after five cycles ascribed to its favorable structural stability. A mechanism of photocatalytic degradation of tetracycline hydrochloride and possible degradation pathways were proposed. This work provides a new growth strategy for constructing highly active and stable visible light-driven TiO2-based composite photocatalysts for effectively treating organic pollutants.

Interfacial Coupling‐Induced Pseudocapacitance in LiFePO4@Polypyrrole Heterostructures Toward High‐Rate Lithium Storage

The olivine‐structured LiFePO4 (LFP) materials are widely used as commercial cathodes due to its high thermal/chemical stability, long cycle life, low price, etc. However, the poor high‐rate performance severely hinders its high‐power applications due to intrinsically diffusion‐controlled lithium storage. Herein, an interfacial coupling‐induced pseudocapacitance (ICIPC) strategy to realize high‐rate capacity lithium storage of LiFePO4@ polypyrrole (LFP@PPY) is provided. The strong interfacial coupling interaction between LFP and polypyrrole (PPY) promotes interfacial pseudocapacitance as a major Li+ storage mechanism during the charge/discharge process at high rates. The dynamic combination of interfacial and diffusion lithium storage of electrodes can enhance reaction kinetics, the rate capability and cyclic performance. In addition, the nanoscale PPY coating layer effectively improves the surface conductivity of the LFP particles and the charge transfer kinetics of electrochemical reactions. Therefore, the LFP@PPY cathode exhibits remarkable rate capability with a capacity of 105 mAh g−1at 10 A g−1 and 84 mAh g−1 at 20 A g−1 and excellent cyclic stability performance with the initial capacity of 106.7 mAh g−1 at 10 C (91.2 mAh g−1 after 500 cycles). The ICIPC strategy may be extended to other cathodes (LiCoO2, etc.) to improve the high‐rate performance.

Ultrasensitive and ultrastretchable electrically self-healing conductors

Self-healing is a bioinspired strategy to repair damaged conductors under repetitive wear and tear, thereby largely extending the life span of electronic devices. The self-healing process often demands external triggering conditions as the practical challenges for the widespread applications. Here, a compliant conductor with electrically self-healing capability is introduced by combining ultrahigh sensitivity to minor damages and reliable recovery from ultrahigh tensile deformations. Conductive features are created in a scalable and low-cost fabrication process comprising a copper layer on top of liquid metal microcapsules. The efficient rupture of microcapsules is triggered by structural damages in the copper layer under stress conditions as a result of the strong interfacial interactions. The liquid metal is selectively filled into the damaged site for the instantaneous restoration of the metallic conductivity. The unique healing mechanism is responsive to various structural degradations including microcracks under bending conditions and severe fractures upon large stretching. The compliant conductor demonstrates high conductivity of ∼12,000 S/cm, ultrahigh stretchability of up to 1,200% strain, an ultralow threshold to activate the healing actions, instantaneous electrical recovery in microseconds, and exceptional electromechanical durability. Successful implementations in a light emitting diode (LED) matrix display and a multifunctional electronic patch demonstrate the practical suitability of the electrically self-healing conductor in flexible and stretchable electronics. The developments provide a promising approach to improving the self-healing capability of compliant conductors.