High-efficiency Strategy Research Articles

Rational Strategies for Preparing Highly Efficient Tin-, Bismuth- or Indium-Based Electrocatalysts for Electrochemical CO2 Reduction to Formic acid/Formate.

Electrochemical carbon dioxide reduction reaction (CO2RR) is an environmentally friendly and economically viable approach to convert greenhouse gas CO2 into valuable chemical fuels and feedstocks. Among various products of CO2RR, formic acid/formate (HCOOH/HCOO-) is considered the most attractive one with its high energy density and ease of storage, thereby enabling widespread commercial applications in chemical, medicine, and energy-related industries. Nowadays, the development of efficient and financially feasible electrocatalysts with excellent selectivity and activity towards HCOOH/HCOO- is paramount for the industrial application of CO2RR technology, in which Tin (Sn), Bismuth (Bi), and Indium (In)-based electrocatalysts have drawn significant attention due to their high efficiency and various regulation strategies have been explored to design diverse advanced electrocatalysts. Herein, we comprehensively review the rational strategies to enhance electrocatalytic performances of these electrocatalysts for CO2RR to HCOOH/HCOO-. Specifically, the internal mechanism between the physicochemical properties of engineering materials and electrocatalytic performance is analyzed and discussed in details. Besides, the current challenges and future opportunities are proposed to provide inspiration for the development of more efficient electrocatalysts in this field.

Boosting K+-Ionic Conductivity of Layered Oxides via Regulating P2/P3 Heterogeneity and Reciprocity for Room-Temperature Quasi-Solid-State Potassium Metal Batteries.

Solid-state potassium metal batteries are promising candidates for grid-scale energy storage due to their low cost, high energy density and inherent safety. However, solid state K-ion conductors struggle with poor ionic conductivity due to the large ionic radius of K+-ions. Herein, we report precise regulation of phase heterogeneity and reciprocity of the P2/P3-symbiosis K0.62Mg0.54Sb0.46O2 solid electrolyte (SE) for boosting a high ionic conductivity of 1.6×10-4 S cm-1 at 25 °C. The bulk ionic conducting mechanism is explored by elucidating the effect of atomic stacking mode within the layered framework on K+-ion migration barriers. For ion diffusion at grain boundaries, the P2/P3 biphasic symbiosis property assists in tunning the SE microstructure, which crystallizes in rod-like particles with lengths of tens of micrometers facilitating long-distance ion transport and significantly decreasing grain boundary resistance. Potassium metal symmetric cells using the modified SE deliver excellent cycling life over 300 h at 0.1 mA cm-2 and a high critical current density of 0.68 mA cm-2. The quasi-solid-state potassium metal batteries (QSSKBs) coupled with two kinds of layered oxide cathodes demonstrate remarkable stability over 300 cycles, outperforming the liquid electrolyte counterparts. The QSSKB system provides a promising strategy for high-efficiency, safe, and durable large-scale energy storage.

A high-efficiency strategy for fruit preservation using green, natural raw materials

Straw is an abundant renewable biomass resource material. Lignin contained in straw is a unique natural aromatic compound in nature. At present, it is urgent to find ways to realize the higher value of natural lignin resources. In this study, alkali lignin was separated from rice straw by hydrothermal method in NaOH solution, which was prepared lignin nanoparticles by a simple green anti-solvent method. The obtained lignin nanoparticles had excellent anti-tyrosinase activity (IC50 = 0.329 mg mL−1) and anti-oxidation performance (IC50 = 0.0451 mg mL−1). Meanwhile, through the analysis of tyrosinase inhibition kinetics, it is concluded that the tyrosinase inhibition by lignin nanoparticles belongs to mixed inhibition. The affinity of lignin nanoparticles to the free enzyme is greater than that of enzyme and substrate complex. In addition, lignin nanoparticles were added to chitosan solution for compounding, then the composite films for fruit preservation were prepared by casting method. The experimental results show that the composite membrane can effectively extend the shelf life of fruits, which is expected to achieve a broader application in the field of fruit preservation and food packaging.

Dual-Mechanism Design Strategy for High-Efficiency and Long-Lived Organic Afterglow Materials.

Organic room-temperature phosphorescence (RTP) and afterglow materials hold great potential for various applications, but there remain inherent trade-offs between the afterglow efficiency and the lifetime. Here, we propose a dual-mechanism design strategy, leveraging the RTP or thermally activated delayed fluorescence (TADF) mechanism for a high afterglow efficiency and the organic long-persistent luminescence (OLPL) mechanism for a prolonged afterglow duration. The intramolecular charge transfer (ICT)-type difluoroboron β-diketonate molecules with a large S1 dipole moment are doped as the luminescent component into the organic matrix with a large dipole moment, and a series of TADF-type afterglow materials can be achieved with an afterglow efficiency of up to 88.7% and an afterglow lifetime of 200 ms. To prolong the afterglow duration, an electron donor is introduced as the third component to generate traps and facilitate charge separation. The obtained materials exhibit a dual afterglow mechanism, first exhibiting a TADF/RTP afterglow with an afterglow efficiency of up to 50.9%, followed by an hours-long OLPL afterglow emission with an afterglow efficiency of up to 13.1%. Further investigations reveal that an appropriate heavy-atom effect can facilitate the intersystem crossing process, which can promote the charge separation process and thus improve the OLPL afterglow performance. Additionally, rare-earth upconversion materials are introduced into OLPL materials to enable their near-infrared excitation properties, showcasing their potential applications in bioimaging.

Selective extraction of genomic DNA from leopard cat (Prionailurus bengalensis), hairy-crowned deer (Elaphodus cephalophus) and muntjac (Muntiacus reevesi) using hydrophobic magnetic deep eutectic solvents

Wild animals, as a vital component of our natural world, serve a crucial role in preserving ecological equilibrium and biodiversity. By delving into the genetic constitution of wild animal populations, the evolutionary history, genetic diversity, and adaptation mechanisms could be explored, thereby informing conservation strategies and safeguarding the future of these species. In order to study the genetic information of wild animals, it is necessary to extract high purity and high concentration of wild animal genomic DNA. In this work, a hydrophobic magnetic deep eutectic solvent (HMDES) based vortexed extraction was developed for the extraction of genomic DNA from leopard cat (Prionailurus bengalensis), hairy-crowned deer (Elaphodus cephalophus) and muntjac (Muntiacus reevesi) muscle tissue, respectively. Extraction conditions like the pH value, extraction time, temperature and the amount of HMDES used were optimized by single-factor experiments. Under the optimized condition, genomic DNA could be selectively extracted from the three animal tissues. The limits of detection (LOD) and limits of quantification (LOQ) of the proposed method were 2.86 ng/μL and 8.66 ng/μL, respectively. Meanwhile, the relative standard deviation (RSD) of the method precision and repeatability were 1.64 % and 5.57 % at 20 ng/μL, showing the method has good precision and repeatability. After extraction, the DNA extracted into the HMDES droplets can be quickly recovered and the HMDES can be recycled and reused. The method proposed is a fast, environmental-friendly and high efficient extraction strategy for purification and enrichment of genomic DNA from leopard cat, hairy-crowned deer and muntjac tissues.

Li-Ion Batteries with a Binder-Free Cathode of Carbon Nanotubes-LiFePO4-Al Foam

With the increasing demand for Li resources worldwide, the easy recycling of Li-ion batteries materials becomes essential. We report a binder-free cathode consisting of carbon nanotubes (CNTs) and LiFePO4 (LFP) nanoparticles embedded in a 3D Al network. The electrode stability depends on the CNT ratio, where 3% CNT-wrapping LFPs provide a stable structure free of detachment from Al foam, as observed on Al foil. The binder-free cathode sheet exhibited excellent performance for high-rate discharge and long-term cycle life. Materials on the cathode can be easily detached with ultrasonic treatment when immersed in organic solvent, which is advantageous for a green and high-efficiency strategy of recycling all valuable materials compared to the binder-used electrode.

One-step light-induced hierarchical surface wrinkles on photodegradable polymer films

Photodegradable polymers have become an emerging class of stimulus-sensitive materials for advanced applications, in which using the photolysis characteristic for patterning surface is a key but still a notable challenge. Herein, we report a simple, facile, green and high-efficiency strategy to induce and further tune surface wrinkling only relying on one-step ultraviolet (UV) irradiation of a photodegradable polymer-based film/substrate composite system. Interestingly, a series of intriguing wrinkling states from no wrinkling to surface wrinkling and final no wrinkling with UV exposure take place on the photodegradable polymer film. This wrinkling behavior is intimately related to the competition between the stress accumulation from the heating effect of UV lamp itself and the stress release from the UV-induced molecular chain breakage. Meanwhile, the dependence of photodegradable polymer film modulus and photodegradation-induced stress release on the exposure time has been characterized by taking advantage of surface wrinkling metrology, which is not easily accessible to other systems and methods. This one-step light irradiation strategy has enabled the fabrication of diverse hierarchical surface wrinkling on photodegradable polymer film by simply controlling the UV exposure time. As demonstrated, these hierarchical surface wrinkles with tunable features have been applied for optical information display/storage and optical gratings. Notably, this simple flexible light control strategy not only provides new insights into the photo-induced change in mechanical properties and stress release of photodegradable polymers in molecular level, but also paves new avenues for advanced wrinkle-based applications by incorporating desirable functional materials into the photodegradable polymer-based systems.

Green and efficient extraction of polyphenols from the leaves of Quercus dentata Thunb and in vitro antioxidant activities of polyphenol extract

The ultrasonic-coupled deep eutectic solvents method was firstly applied to extract phenolic compounds efficiently from the leaves of Quercus dentata Thunb. Five factors including type of deep eutectic solvent, water content, solid-liquid ratio, extraction time and extraction temperature were investigated based on total polyphenol content. The optimal extraction parameters were obtained through response surface methodology, that is, the deep eutectic solvent was composed of choline chloride and 1, 4-butanediol (molar ratio 1:2) with water content of 38%, the solid-liquid ratio was 1:30 g/mL, the extraction time was 31 min, the extraction temperature was 55 °C. At this condition, total polyphenol content reached the highest value of 78.56 ± 2.44 mg gallic acid/g. In addition, eleven phenolic compounds were identified by high performance liquid chromatography quadrupole/time-of flight mass spectrometry as flavonol glycosides. And then, the extraction showed good antioxidant activities in reducing transition metals (Fe3+, Cu2+, Mo6+) and scavenging free radicals (DPPH·, ABTS+·, O2−· and ·OH). Among them, the IC50 values of scavenging DPPH·, ABTS+·, O2−· and ·OH free radicals were 10.87 ± 0.25 μg mL−1, 8.04 ± 0.24 μg/mL, 149.47 ± 5.27 μg/mL and 131.73 ± 5.31 μg/mL, respectively. On the other hand, the extraction at the cellular level exerted its protective effect on PC12 cells by increasing the cell survival rate of H2O2-induced damaged cells, weakening the level of reactive oxygen species in damaged cells. Overall, this study provided a green and high-efficient strategy for extracting phenolic compounds with great antioxidant activities from Q. dentata leaves.

Multiparticle Synergistic Electrophoretic Deposition Strategy for High-Efficiency and High-Resolution Displays.

Colloidal nanoparticles offer unique photoelectric properties, making them promising for functional applications. Multiparticle systems exhibit synergistic effects on the functional properties of their individual components. However, precisely controlled assembly of multiparticles to form patterned building blocks for solid-state devices remains challenging. Here, we demonstrate a versatile multiparticle synergistic electrophoretic deposition (EPD) strategy to achieve controlled assembly, high-efficiency, and high-resolution patterns. Through elaborate surface design and charge regulation of nanoparticles, we achieve precise control over the particle distribution (gradient or homogeneous structure) in multiparticle films using the EPD technique. The multiparticle system integrates silicon oxide and titanium oxide nanoparticles, synergistically enhancing the emission efficiency of quantum dots to a high level in the field. Furthermore, we demonstrate the superiority of our strategy to integrate multiparticle into large-area full-color display panels with a high resolution over 1000 pixels per inch. The results suggest great potential for developing multiparticle systems and expanding diverse functional applications.

Photothermal Welding Strategy for Mechanical Stability and High Efficiency of ETL‐Free f‐PSCs

AbstractFlexible perovskite solar cells (f‐PSCs) have drawn widespread interest owing to their distinguished advantages in excellent flexibility and relatively low cost. However, the brittle grain boundaries (GBs) and defects in flexible perovskite film tremendously influence the power conversion efficiency (PCE) and mechanical flexibility of f‐PSCs. Herein, photothermal welding, a novel method, is used to improve the perovskite films quality and the PCE of f‐PSCs with a near‐infrared (NIR) dye (indocyanine green, ICG) and polycaprolactone (PCL) as additives. Due to the strong photothermal effect, ICG molecule not only can significantly enhance NIR light harvesting, but it also can weld GBs upon exposure to an NIR laser, which is conducive to the GBs connections and device flexibility. Meanwhile, the S═O bond of ICG and C═O bond of PCL can simultaneously coordinate with Pb2+ defects in perovskite. Furthermore, they can control crystal growth to form a smooth surface of perovskite film. Consequently, the unencapsulated PSCs based on ICG/PCL displays a high champion PCE of 20.62%, with 88.4% of the original PCE after being placed in dark conditions for 600 h. The f‐PSCs delivers a champion PCE of 19.55% and exhibits excellent mechanical stability, thus providing a meaningful scientific direction to fabricate high‐flexible f‐PSCs.

A facile high-efficiency preparation strategy for Al-containing multi-component boride microcrystals with superior comprehensive performance

Multi-component transition group metal borides (MMB2) have become a research hotspot due to their new composition design concepts and superior properties compared with conventional ceramics. Most of the current methods, however, are complicated and time-consuming, the mass production remains a challenge. Herein, we proposed a new high-efficiency strategy for synthesis of MMB2 using molten aluminum as the medium for the first time. The prepared Al-containing multi-component borides (TiZrHfNbTa)B2 microcrystals had a homogeneous composition with a hexagonal AlB2 structure and ultra-high hardness value of ∼35.3 GPa, which was much higher than data reported in the literature and the rule of mixture estimations. Furthermore, combined with the First-principles calculation results, we found that the Poisson's ratio (v) values exhibit a clearly ascending trend from 0.17 at VEC = 3.5 to 0.18 at VEC = 3.4, then to 0.201 at VEC = 3.2 with the increasing of Al content. This indicates that the intrinsic toughness of multi-component boride microcrystals is obviously enhanced by the trace-doped Al elements. Besides, the fabricated Al-containing multi-component boride microcrystals have superior oxidation activation energy and structural stability. The enhanced oxidation resistance is mainly attributed to the formation of a protective Al2O3 oxide layer and the lattice distortion, both of which lead to sluggish diffusion of O2. These findings propose a new unexplored avenue for the fabrication of MMB2 materials with superior comprehensive performance including ultra-hardness and intrinsically improved thermo-mechanical properties.

Studying the nonlinearity effects in ultrasound-assisted water purification and treatment systems

In light of industrial sectors' rapid and exponential growth, the deleterious specter of water pollution looms ominously over our environment. One of the significant challenges is obtaining a sustainable and energy-efficient water purification/treatment system. Since the 1990s, several research studies have been proposed to demonstrate the usefulness of ultrasound as a water purification tool. As a result, newly designed devices such as ultrasound-assisted electrochemical treatment and ultrasound-assisted heat exchanging devices are becoming more common. However, such devices' high voltage ultrasonic emission is a significant problem because the nonlinear acoustic effects are not well understood and are, therefore, not adequately integrated into the design of the devices. Furthermore, the presence of biofilms in these devices creates more complexity due to the interaction of high-amplitude ultrasonic waves with the biofilm network. To better overcome the inefficient functioning of such devices and adverse operational issues, the current study aims to investigate and explain the nonlinear ultrasonic effects in ultrasonic-assisted purification devices, with and without biofilm deposits. The obtained insight will help develop an effective design strategy for high efficiency.

Utilization of ovalbumin and visible light irradiation for efficient and eco‐friendly production of AgNPs composite

Silver nanoparticles (AgNPs) are one of the most widely used antimicrobial agents. However, due to the potential problems of environmental pollution and high energy consumption, a green and efficient synthesis strategy of AgNPs is urgently required. Ovalbumin (OVA) is the most abundant protein in egg whites, and its extraction process is simple and productive. This paper reported a new green synthesis method of AgNPs by using OVA as an assistant accompanying with a visible light irradiation. Together with the reduction of silver ions, the uniformly dispersed OVA‐AgNPs nanocomposite could be formed within 30 min under xenon light irradiation by simple mixing AgNO3 and OVA in aqueous solution. The detailed mechanism study showed that tyrosine residue and peptide bonds in OVA played a major role in the reduction and stability of silver ions. In addition, in vitro antibacterial experiments indicated that 10 mg/L of OVA‐AgNPs, the minimum inhibitory concentration, has a good antimicrobial effect on both Gram‐positive and Gram‐negative bacteria, fungi, and some drug‐resistant bacteria species within 4 h of treatment, mainly due to the disruption of the structure of bacterial cell and the balance of reactive oxygen species. This work provides a new way for the green and efficient synthesis of AgNPs and shows good prospects for the applications in the field of biomedical materials and functional nanomaterials.

Reversible hydrogen storage and release mechanism of a B2N monolayer: a first-principles insight.

It was found the physical adsorption could be an efficient strategy for high capacity, high efficiency and high safety in hydrogen storage. In this research, a systematic investigation into the potential of the B2N monolayer as an excellent physical adsorption hydrogen storage material is conducted by utilizing the first-principles calculation method. The findings of the investigation demonstrate that the B2N monolayer has a planar lattice and excellent structural stability. It is possible for H2 molecules to adsorb onto the B2N monolayer spontaneously. Both the individual adsorption and saturation adsorption corresponded to average adsorption energies ranging from -0.221 to -0.194 eV, fulfilling the physical adsorption criteria. In the case of saturation adsorption, a 1 × 2 × 1 B2N supercell can store a total of 24 H2 molecules, with the hydrogen gravimetric density up to 14.511 wt% and volumetric density up to 138 g L-1. A semi-empirical calculation method is used to research the performance of the system in terms of adsorption and desorption with actual temperature and pressure conditions. Under the actual conditions with adsorption carried out at 30 atm/233 K and desorption carried out at 3 atm/358 K, the maximal reversible hydrogen storage capacity of the hydrogen storage system based on the B2N monolayer can still reach 12.157 wt%, which is superior to that of many other boron-nitrogen compounds and metal-free functionalized hydrogen storage materials. The findings of this work indicate that the pristine B2N monolayer is one of the promising physical adsorption materials which could achieve excellent reversible hydrogen storage under defined conditions.

Fabrication of sustainable flame retardant cotton fabrics via foam finishing with sodium polyborate

The conventional process of imparting flame retardancy to cotton fabrics requires the consumption of large amounts of water, chemicals, and energy, which usually involves halogen-containing and phosphorus-containing chemicals. In this work, an eco-friendly sodium polyborate (SPB) foam was creatively introduced onto the cotton fabric surface by a bladed coater to improve the fire resistant performance. For the cotton sample with only 6.7% weight gain (WG) of SPB coating, the LOI value of cotton fabric (SPB treated cotton-1) was enhanced to 32.6% from 18.5%, the damaged length was decreased to 5.7 cm, and the sample self-extinguished in the vertical burning test. The peak of heat release rate value, total heat release value, and total smoke production (TSP) value decreased by 87.0%, 72.7%, and 22.2% respectively compared with those of the control sample. The TSP was further decreased by 80.6% when the WG of SPB was 16.7%. Besides, the SPB treated cotton showed enhanced antibacterial activities against S.aureus and E.coli. Particularly worth mentioning is in the SPB foam finishing procedure, no organic solvent and P or Cl-containing chemicals were involved, and the processing time was only around 3 min with obviously reduced water consumption, compared with dip-padding finishing. More importantly, SPB treated cotton kept good softness, whiteness, water vapor permeability, and air permeability. The SPB foam finishing in this work shows considerable potential in realize good flame retardancy on cotton fabrics by eco-friendly and high-efficient strategy.

Mechanism of sulfite enhanced As(III) oxidation in the As(III)-Fe minerals under ambient conditions

Iron (Fe) minerals are known to be effective adsorbents for arsenic (As). However, the effects of sulfur species formed from the reductive dissolution of Fe minerals on the transformation of As(III) during the redox fluctuations processes under ambient conditions were poorly understood. Herein, we synthesized the As(III)-Fe minerals using sodium arsenite and ferric nitrate to investigate the effects of sulfur species on As(III) transformation in the As(III)-Fe minerals. Experimental results showed that sulfite rather than elemental sulfur and thiosulfate significantly accelerated As(III) oxidation. The oxidation rate of As(III) increased markedly from 0.0050 to 0.0168 min−1 with the increase of sulfite concentration from 0.5 to 2.0 mM. Sulfate radicals (SO4•−) and hydroxyl radicals (•OH) were identified as the dominant reactive species for As(III) oxidation. Besides, the underlying mechanism of Fe(II)/Fe(III) cycling for enhancing As(III) oxidation was further explored in the homogeneous Fe(II)/sulfite systems. Finally, interactions between sulfite and soil components induced radical formation, leading to As(III) oxidation in the soil environments. This study gives new insights into As(III) transformation co-existed with Fe minerals and sulfur species, which shed light on developing remediation strategies for regulating As contamination in temporarily flooded soils. Environmental implication“New Insights into the Mechanism of Sulfur Species Induced As(III) Oxidation in the As-Fe Minerals”This study systematically explored the coupled effects between sulfur species and Fe minerals on As(III) transformation in the As-Fe-minerals under oxic conditions, which showed that sulfite significantly accelerated As(III) oxidation to As(V) via the enhanced formation reactive oxygen species (e.g., SO4•− and •OH). This study shed light on the development of remediation strategies in the contaminated soils with toxic pollutants via introducing sulfur species. We strongly believe this study is of great interest to environmental scientists and chemical engineers, especially those who works on the remediation of contaminated sites and wish to explore the high-efficiency strategies for the control of toxic pollutants like As.

Hydrophobic Trinuclear Copper Cluster-Containing Organic Framework for Synergetic Electrocatalytic Synthesis of Amino Acids.

Electrocatalytic synthesis of amino acids provides a promising green and efficient pathway to manufacture the basic substances of life. Herein, reaction of 2,5-perfluroalkyl-terepthalohydrazide and tris(4-µ2 -O-carboxaldehyde-pyrazolato-N, N')-tricopper affords a crystalline trinuclear copper cluster-containing organic framework, named F-Cu3 -OF. Incorporation of abundant hydrophobic perfluroalkyl groups inside the channels of F-Cu3 -OF is revealed to successfully suppress the hydrogen evolution reaction via preventing H+ cation with large polarity from the framework of F-Cu3 -OF and in turn increasing the adsorption of other substrates with relatively small polarity like NO3 - and keto acids on the active sites. The copper atoms with short distance in the trinuclear copper clusters of F-Cu3 -OF enable simultaneous activization of NO3 - and keto acids, facilitating the following synergistic and efficient C─N coupling on the basis of in situ spectroscopic investigations together with theoretical calculation. Combination of these effects leads to efficient electroproduction of various amino acids including glycine, alanine, leucine, valine, and phenylalanine from NO3 - and keto acids with a Faraday efficiency of 42%-71% and a yield of 187-957µmol cm-2 h-1 , representing the thus far best performance. This work shall be helpful for developing economical, eco-friendly, and high-efficiency strategy for the production of amino acids and other life substances.

Multiphase nano Co9S8/CoS encapsulated in N-doped carbon for high capacity sodium-ion battery anode

As anode materials for sodium-ion batteries (SIBs), transition metal sulfides (TMSs) have been widely explored due to their low cost, high theoretical capacity and rich redox reactions. However, poor cycling performance and capacity retention limit the application of materials. In this work, multiphase nano Co9S8/CoS encapsulated in N-doped carbon for high capacity SIBs anode is prepared via a facile two-step strategy: precipitation and heat treatment. When applied as anodes for SIBs, mass capacity of 389.2 mAh g−1 at 0.1 A g−1 after 60 cycles is obtained, and delivered ~300 mAh g−1 from 2nd to 300th cycle without depravation under 1.0 A g−1. In addition, according to the calculation of Na+ diffusion kinetics, it is evident that carbon encapsulation not only helps prevent electrolyte erosion but also enhances the DNa+ of the anode material. The high efficient strategy can be applied to synthesis of other multiphase analogues. Based on theoretical investigations, calculations of band gaps and rebuild energies for other TMSs (i.e., Cu7S4/Cu2S, FeS/Fe21.333O32/Fe3O4, MnS2/MnS, Ni3S2/Ni3C and cubic-ZnS/hexagonal-ZnS), as well as analysis of cyclic data, it can be concluded that Co9S8/CoS@NC material exhibits the highest conductivity and cycle stability.

Photodynamic-responsive gelatin-based coating with high utilization curcumin loaded bilayer nanoencapsulation: A promising environmental food packaging

The development and application of curcumin-mediated antimicrobial photodynamic techniques (PDT) in food preservation are highly anticipated to resist microbial contamination and prevent food spoilage. In this study, high-utilization curcumin-loaded bilayer nanoencapsulation was prepared to incorporated into a gelatin-based edible coating for beef preservation. Bilayer nanoencapsulation composed of shellac and poly-γ-glutamic acid (CS-NPs) improved the encapsulation efficiency of shellac to curcumin by >1.5 times. The incorporation of CS-NPs improved the compact of coating structure with hydrogen bonds. In food simulants, coatings possessed control release properties and the release mechanism was Fick diffusion (without the addition of γ-PGA) and non-Fick diffusion (with the addition of γ-PGA). These prepared coatings exhibited excellent barrier, antibacterial (antibacterial ratio > 95 %), and antioxidant properties (scavenging ratio > 90 %). Curcumin mediated antimicrobial photodynamic techniques (PDT) of the coatings were verified with the activity of blue light-induced reactive oxygen species (ROS). The shelf-life of beef was extended by the coating with blue light. In summary, the design of bilayer CS-NPs significantly improved the utilization of curcumin which provided a high-efficiency strategy for PDT-responsive food packaging with environmental practical.

Achieving superior strength-ductility synergy in a unique multi-scale heterostructured titanium laminate fabricated by temperature-controlled rolling and subsequent annealing

Here we proposed a low-cost and high-efficiency strategy for fabricating novel multi-scale gradient-structured/heterogeneous lamella structured (GS/HLS) pure titanium laminates with superior strength-ductility synergy, by temperature-controlled rolling and subsequent annealing of as-sintered multilayered pure titanium foils with preset grain size gradient. A preliminary gradient structure with the average grain size decreasing from the center layer (alternating stacking of equiaxed fine grain bands and elongated grain bands) to the surface layer (equiaxed fine grains) is formed by optimizing the rolling process. Generalized Schmidt factor analysis based on electron backscatter diffraction indicated that there were slip-dominated and twin-dominated grain refinement mechanisms during the rolling process. In addition to the prismatic slip, two kinds of contraction twinning could be activated to achieve the grain refinement in hard domains where slip systems were hard to be activated. After subsequent annealing, equiaxed fine grains in the laminates did not significantly coarsen, while the elongated grains in the center layer had partially merged and grew up into the elongated coarse grains. Thus, the microstructure of the center layer displayed a typical heterogeneous lamella structure composed of alternately stacking of elongated coarse grains and fine grain bands, together with the grain size gradient, a unique multi-scale heterostructured titanium laminate was formed. Tensile test indicated that the as-rolled Ti laminates exhibited extremely high ultimate tensile strength (UTS) of 930 MPa with an acceptable total elongation to fracture (ETF) of 12.3 %, while GS/HLS Ti laminates after annealing at 425 °C possessed a superior combination of high UTS (823 MPa) and high ETF (22.4 %). The main reason was that the annealing treatment significantly reduced the dislocation density in the elongated coarse grains of GS/HLS Ti laminates. This meant that more geometrically necessary dislocations (GNDs) could accumulate in the plastic deformation process, resulting in the hetero-deformation induced (HDI) strengthening and an extra HDI hardening caused by the unique GS/HLS structure, therefore, an excellent strength-ductility synergy of final GS/HLS Ti laminates was achieved.