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A novel polyimide copolymer (ZnTPP-PI) was synthesized through molecular engineering and a copolymerization method, which achieves high energy storage density, and excellent thermal stability and mechanical properties.

Rational design and facile preparation of low-cost and efficient catalysts for the selective converting of biomass-derived monosaccharides into high value-added chemicals is highly demanded, yet challenging. Herein, we first demonstrate a N doped defect-rich carbon (NC-800-5) as metal-free catalyst for the selective oxidation of d -xylose into d -xylonic acid in alkaline aqueous solution at 100 °C for 30 min, with 57.4% yield. The doped graphitic N is found to be the active site and hydroxyl ion participating in the oxidation of d -xylose. Hydroxyl ion and d -xylose first adsorb on NC-800-5 surface, and the aldehyde group of d -xylose is catalyzed to form germinal diols ion. Then, C–H bond break to yield carboxylic group. Furthermore, NC-800-5 catalyst shows high stability in recycled test.

Three-dimensional (3D) printing has attracted more attention in food industry because of its potential advantages, including the ability to create customized products according to individual's sensory or nutritional requirements. However, the production of high-quality 3D printed foods requires the availability of edible bio-inks with the required physicochemical and sensory attributes. Starch, as one of the important sources of dietary energy, is widely used in food processing and is considered as one kind of versatile polymers. It is not only because starch has low prices and abundant sources, but also because desirable modified starch can be obtained by altering its physicochemical properties through physical, chemical and enzymatic methods. This article focuses on the utilization of starch as materials to create food-grade bio-inks. Initially, several kinds of commonly used 3D printers are discussed. The factors affecting the printing quality of starch-based materials and improvement methods are then reviewed, as well as areas where future researches are required. The applications of 3D printed starch-based materials in food industry are also introduced. Overall, starch appears to be one kind of useful substances for creating edible bio-inks that can be utilized within 3D food printing applications to create a wide variety of food products.

Renewable and low-cost biomass is an ideal sustainable alternative to petroleum-based resources, but producing biomass-based carbon electrode with high performances remains a challenge. Herein, we propose a facile self-assembly strategy to fabricate a biomass-derived N, S co-doping carbon electrode from lignosulfonate without any activation or template process. Taking advantage of the coordination between Fe ions and lignosulfonate, the resultant carbon exhibits a spherical structure with abundant graphitized nanosheets, leading to a high specific surface area with rational pore structure, which are beneficial to the electron/ion transport and storage. The high contents of doping N (8.47 wt%) and S (2.56 wt%) significantly boost the electrochemical performances. As a supercapacitor electrode, the carbon material displays high specific capacitance of 390 F g−1, excellent cycling stability and high energy density of 14.7 W h kg−1 at a power density of 450 W kg−1. This study provides a potential strategy for synthesizing cost-effective heteroatom-doped carbon materials from biomass with abundant functional groups and heteroatom sources, such as chitosan, collagen, and gelatin. Graphical Abstract

Formation and investigation of zein/carboxymethyl cellulose composite nanoparticles to co-deliver quercetin and resveratrol.

With the rapid development of wearable and intelligent flexible electronic devices (FEDs), the demand for flexible energy storage/conversion devices (ESCDs) has also increased. Rechargeable flexible metal‐air batteries (MABs) are expected to be one of the most ideal ESCDs due to their high theoretical energy density, cost advantage, and strong deformation adaptability. With the improvement of the device design, material assemblies, and manufacturing technology, the research on the electrochemical performance of flexible MABs has made significant progress. However, achieving the high mechanical flexibility, high safety, and wearable comfortability required by FEDs while maintaining the high performance of flexible MABs are still a daunting challenge. In this review, flexible Zn‐air and Li‐air batteries are mainly exemplified to describe the most recent progress and challenges of flexible MABs. We start with an overview of the structure and configuration of the flexible MABs and discuss their impact on battery performance and function. Then it focuses on the research progress of flexible metal anodes, gel polymer electrolytes, and air cathodes. Finally, the main challenges and future research perspectives involving flexible MABs for FEDs are proposed.

Low-cost and high-performance bifunctional electrocatalysts for efficient oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) are vital for the applications of rechargeable Zn-air batteries (ZABs). Herein, a porous carbon material is fabricated by traditional pulp and papermaking and carbonization process from bamboo. The resultant carbon paper catalyst possesses a high surface area, porous structure and high content of nitrogen. Benefiting from these characteristics, this material exhibits remarkable ORR and OER catalytic performances. The aqueous rechargeable Zn-air batteries assembled with this catalyst exhibit a high power density of 279.5 mW cm−2. This work paves an encouraging way for the industrial production of cost-effective catalysts in a sustainable manner.

A bamboo derived N-doped carbon displayed superior ORR/OER activity and successfully served as a bulk-phase air cathode for a rechargeable zinc–air battery.

Biomass-based protic ionic liquids (BILs), green solvents with inherent properties, have the potential as precursors of functionalized catalytic carbon materials. Simple one-step design and preparation of BILs-based porous carbon-based materials remains a challenge. Our demonstration here was to use BIL as an important precursor for synthesizing porous carbon-coated CoP nanocrystals by facile one-pot carbonization process. The as-prepared CoP@NPC-900 has a specific surface area of 979.67 m2 g−1 without activator and simultaneously exhibits excellent hydrogen evolution reaction (HER) performance with a low overpotential of 181 mV at 10 mA cm−2 and small Tafel slope of 59 mV dec−1 in acid solution. In addition, density functional theory (DFT) calculations indicate lower adsorption free energy and rapid electron transfer between CoP nanocrystals and N, P co-doped porous carbon (NPC) are key factors of improving the HER performance. Our research opens up a new use of BILs, as well as provides a facile strategy to promote practical application of transition metal phosphides for HER.

The preparation of inexpensive, high-performance non-noble metal catalysts for selective oxidation of biomass-derived monosaccharides to high value-added chemicals is challenging but in high demand. Herein, we successfully synthesized a nickel-embedded carbon nanotube (Ni-NCNT) catalyst to selectively convert the monosaccharides into sugar acids under mild condition. The Ni-NCNT catalyst was highly reactive towards glucose and xylose oxidation, reaching 90.8% yield of gluconic acid and 88.4% yield of xylonic acid under the optimal condition. Theoretical calculations revealed that the intrinsic reaction mechanism of xylose oxidation involves the activation of the oxidant, adsorption of xylose, dissociation of the formyl C–H bond in xylose, formation of chemisorbed xylonic acid, and desorption of xylonic acid. The dissociation of the formyl C–H bond and the formation of adsorbed xylonic acid are key steps in the oxidation of xylose. The OH−, instead of O2, acted as a direct oxidant and was crucial for the xylose oxidation. The highly active and cost-effective Ni-NCNT developed in this study provided a promising route to generate valuable chemicals from biomass.

Oral administration of combinations of specific nutrients and nutraceuticals can provide synergistic health benefits to humans. In this work, zein/carboxymethyl cellulose composite nanoparticles were successfully prepared using antisolvent precipitation methods. Zein/carboxymethyl cellulose nanoparticles with the smallest size (204.6 nm) were formed when the mass ratio of zein to CMC was 2 : 1. Hydrogen bonding and hydrophobic interactions were dominant binding forces to stabilize the composite nanoparticles. Quercetin and resveratrol were then encapsulated within these nanocarriers, which improved their resistance to both light and thermal degradation. Encapsulation of the nutraceuticals was shown to delay their release under simulated gastrointestinal conditions, which may be beneficial for some applications. Moreover, encapsulation increased the

High dielectric (high-k) polymer matrix composites (PMCs) have attracted much attention owing to their moderate dielectric property, good thermal stability, and excellent mechanical flexibility, as well as facile processability, light weight, and low cost. Herein, we report an in-situ synthesis strategy to fabricate high-performance high-k PMCs. A novel perovskite CsPbBr3/rGO/polyimide composite is fabricated by in-situ polymerization of poly(amic acid) (PAA) followed by thermal imidization, in-situ chemical reduction of graphene oxide (GO), and in-situ crystallization of CsPbBr3 nanoparticles. The fillers are uniformly dispersed in the polyimide (PI) matrix due to the multiple in-situ conversion processes, which form numerous micro-capacitors to enhance the dielectric permittivity. Attributing to the synergetic effect between rGO and CsPbBr3 nanocrystals, the CsPbBr3/rGO/PI composite showed a high dielectric permittivity up to 213, a high energy storage density of up to 5.20 J cm−3, and a dielectric loss less than 0.35. Besides, the thermal stability of the composites is enhanced (5% weight loss temperature (T5%) > 523 °C), and the mechanical strength is well retained under a relatively low filling amount of fillers (10 wt% CsPbBr3). Therefore, the as-fabricated CsPbBr3/rGO/PI composites would be promising for applications in energy storage polymer thin-film capacitors, and this research also opens a new avenue to fabricate high-k PMCs with good comprehensive properties.

Interfacial design is one of the most promising ways in improving mechanical properties of nanocomposites. In this work, a multifunctional aerogel with excellent mechanical performances, sensing sensitivity, and fire retardancy is fabricated by taking advantage of metal coordination between biopolymer and Fe3+. Montmorillonite (MMT) nanosheets are added to induce a ‘brick and mortar’ structure. The coordination remarkably reduces structural defects, leading to well-formed lamellas that can effectively distribute stress under sever compression without plastic deformation. The structural merits impart the aerogel highly reversible compressibility even at 99 % strain and superior durability. Besides, it demonstrates high sensing performance in wearable health monitoring devices, and shows fire resistance property that can maintain elasticity in a flame. The work offers a facile and effective method to create multifunctional aerogels from various polymers.

In this work, rutin (RT)–loaded zein–carboxymethyl starch (CMS) nanoparticles were successfully prepared by the antisolvent precipitation method. The effect of CMS on composite nanoparticles at different concentrations was studied. When the ratio of zein–RT–CMS was 10:1:30, the encapsulation efficiency (EE) was the highest, reaching 73.5%. At this ratio, the size of the composite nanoparticles was 196.47 nm, and the PDI was 0.13, showing excellent dispersibility. The results of fluorescence spectroscopy, FTIR, XRD, and CD showed that electrostatic interaction, hydrogen bonding, and hydrophobic interaction were the main driving forces for the formation of nanoparticles. It can be seen from the FE–SEM images that the zein–RT–CMS nanoparticles were spherical. With the increase in the CMS concentration, the particles gradually embedded in the cross–linked network of CMS (10:1:50). After RT was loaded on zein–CMS nanoparticles, the thermal stability and pH stability of RT were improved. The results showed that zein–CMS was an excellent encapsulation material for bioactive substances.

Despite the fact that high-valent nickel-based oxides exhibit promising catalytic activity for the urea oxidation reaction (UOR), the fundamental questions concerning the origin of the high performance and the structure-activity correlations remain to be elucidated. Here, we unveil the underlying enhanced mechanism of UOR by employing a series of prepared cation-vacancy controllable LiNiO

Mesoporous graphitic carbon nitride (mpg-C3N4) has been developed as a metal-free heterogeneous photocatalyst for thiocyanation transformations. The reaction proceeds efficiently by utilizing air as a green oxidant under mild reaction conditions, which affords SCN-containing compounds in moderate to excellent yields. Meanwhile, the practicality of this protocol is further demonstrated by the reusability of the mpg-C3N4 photocatalyst and the scaled-up reaction. Furthermore, detailed mechanistic studies clearly demonstrate the role of oxygen.

The selective oxidation of monosaccharides into sugar acids is an important reaction for the production of biomass-based chemicals, but the design of an efficient catalyst remains a big challenge. Herein we report a series of efficient and stable surface functionalized carbon nanotube supported palladium catalysts for the selective oxidation of monosaccharides into sugar acids at room temperature. The palladium nanoparticles supported on alkaline carbon nanotubes (Pd/CNT-N) showed the highest reaction activity. The maximum gluconic acid yield of 98.3% and xylonic acid yield of 95.8% were obtained at 30 °C within 180 min. DFT calculations revealed that the mechanism of xylose oxidation to xylonic acid involved the activation of OH−, adsorption of xylose, dissociation of the formyl C–H bond in xylose, formation of chemisorbed xylonic acid, and desorption of xylonic acid. The activation energy barrier for xylose oxidation over Pd/CNT-N is lower than that of Pd/CNT-O, explaining that the basic groups on CNT are more beneficial for accelerating monosaccharide oxidation and enhancing the sugar acid selectivity. This work not only presents a new facile route to produce sugar acid at room temperature, but also provides a basis to design and develop efficient catalysts with surface functionalized supports for various catalytic reactions.

The development of emulsion templated functional materials has achieved great progress in the past decades in academic and industrial fields. Recently, new building blocks such as graphene, transition metal carbides and nitrides (MXenes) and nanocellulose have been used in the fabrication of emulsion templated functional materials (EFMs). Intrinsic characteristics of these nano building blocks along with the various material formats and structures endow the functional materials with excellent properties and diverse applications. Herein, the latest progresses in emulsion templating mechanisms, emerging nano building blocks, and material formats including monolith, film and microcapsule for EFMs are reviewed first. Typical applications of these functional materials are critically discussed in the fields of sensing, energy storage and conversion, fire resistance and thermal insulation, water purification, and microdroplet transportation. Current challenges, future prospects and research opportunities of EFMs are also discussed finally.

Developing efficient active transition metal phosphide (TMP) bifunctional electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) for alleviating the future energy crisis is crucial and challenging. Herein, we developed a facile self-assembly strategy for the one-step fabrication of core–shell Co2P nanoparticles encapsulated in nitrogen and phosphorus codoped porous carbon (Co2P@NPPC) via in situ carbonization and phosphorization. Due to the collaborative effect between NPPC and Co2P, the obtained Co2P@NPPC hybrid revealed robust electrocatalytic performance toward the HER and OER. Impressively, it exhibited a lower overpotential of 147 mV for HER and 316 mV for OER to reach the current density of 10 mA cm−2. Remarkably, it only required a low cell voltage of 1.65 V to reach the current density of 10 mA cm−2, with long-time reliable stability. Density functional theory (DFT) calculations suggest that the introduction of phosphorus into cobalt can weaken the H-adsorption free energy and increase the electronic states of Co2P.

Synthesis of D-xylonic acid, a high value chemical feedstock, from biomass chemicals through a photocatalytic process is of great significance in respect of economical and sustainable concerns, and therefore has aroused considerable attention. Herein, a TiO2/Ti3C2(TT) photocatalyst was designed for the oxidation of xylose to D-xylonic acid under ambient conditions. The photocatalyst is fabricated by in situ growth of TiO2 nano-particles on Ti3C2 nanosheets and exhibits 64.2% of D-xylonic acid yield with excellent stability. The mechanistic study indicates that the electron transfer from TiO2 to Ti3C2 significantly increases the life time of light-induced charge carriers, and hence improved photocatalytic performance.

Photoreforming of lignocellulose for sustainable H2 generation appears to be a good option at the time that biomass wastes are being degraded. Recently, polymeric carbon nitride (PCN) has emerged as a promising alternative for the photorefoming reaction, however, its photocatalytic performance is largely limited by its severe recombination of charge carriers. Here, we developed an approach, for the first time, to construct a curly-like carbon nitride nanosheets with the formation of in-plane surface dyadic heterostructure for steering the charge transfer and optimizing the electronic band structure. This PCN material shows superior photoreforming H2 evolved activity of 122.77 μmolh−1 (i.e. 4092 μmolh−1g−1) from the aqueous lignocellulose solution (using Pt as cocatalyst), 15.6 folds of pristine PCN under visible light irradiation, together with an apparent quantum efficiency (AQE) of 7.87% (λ = 420 nm). It enables the visible-light-driven conversion of several kinds of lignocellulose including the monosaccharides, disaccharides, hemicellulose, and cellulose. Additionally, when used as a photocatalyst for water splitting, it achieves a remarkable H2 production rate of 22043 μmolh−1g−1 (∼56.0 folds’ increases than pristine PCN) with a superior high AQE of 41.2%, as well as a high CO reduction rate of 56.3 μmolh−1 from the photocatalytic CO2 conversion, 24.5 times than pristine PCN.

Poly(ethylene oxide) (PEO)-based polymer electrolytes are promising candidates for solid-state electrolytes in safer, next generation lithium metal batteries. Despite their benefits however, PEO-based electrolyte exhibits highly crystalline ethylene oxide chains that provide poor ionic conductivity and, thus severely limit its practical application. Here, we report the use of hydroxypropyl trimethylammonium bis(trifluoromethane) sulfonimide chitosan salt (HACC-TFSI), which is an amorphous poly(ionic liquid) based biomass chitosan derivative, as a modifier for PEO-based solid polymer electrolytes (SPEs) to address these deficiencies. Hybrid SPEs with HACC-TFSI display enlarged amorphous regions with enhanced ionic conductivity. Interactions between quaternary ammonium cations and TFSI− anions in hybrid SPEs are also found to promote dissociation between Li+ and TFSI−, which further increases ionic mobility. Moreover, the electrochemical stability, mechanical strength, and thermal stability of hybrid SPEs are collectively superior to blank SPEs without HACC-TFSI. LiFePO4/SPEs/Li full-cells assembled using 10wt% HACC-TFSI in PEO (10%HACC-TFSI/SPEs) electrolyte provide a capacity of 161.3 mAh g−1 and operate with excellent cycle performances at 0.2 C and 60 °C. Even when the temperature is increased to 150 °C, LiFePO4/SPEs/Li cells with 10%HACC-TFSI/SPEs still display remarkable cycle performance with 73% capacity retention after 100 cycles at 1 C rate.

A facile strategy for the preparation of a nanoconfined Ti3C2/Ru cocatalyst by direct reduction of Ru3+ ions without an additional reductant was developed. The in situ formation of TiO2 nanosheets on the Ti3C2/Ru surface ensures the separation of the semiconductor and cocatalyst (TiO2-Ti3C2/Ru), resulting in charge segregation and migration more effective than those achieved by traditionally prepared Ru-TiO2-Ti3C2. Owing to its low Fermi level, the self-assembled Ti3C2/Ru cocatalyst accepted the photogenerated electrons and promoted H2 evolution without an induction period, while exhibiting high surface structure stability. The changes in the work function and surface terminations of Ti3C2 during the photocatalysis were revealed by DFT calculations and in situ diffuse reflectance infrared Fourier transform spectroscopy. The efficient electron transfer enabled by the structurally separated Ti3C2/Ru-based photocatalyst significantly reduced the electron-hole recombination, increasing the photocatalytic H2 evolution activity. This work provides a guiding design approach for future solar energy conversion with the semiconductor-cocatalyst system.

Background: Bio-based materials, as the plentiful and renewable resources for natural constituents which are essential for biomedical and pharmaceutical applications, have not been exploited adequately yet. Chitosan is a naturally occurring polysaccharide obtained from chitin, which has recently attracted widespread attention owing to its excellent activity. This review shows the methods of extraction and modification of chitosan and provides recent progress of synthesis and use of chitosan-based materials in biological applications. Methods: By consulting the research literature of the last decade, the recent progresses of functional chitosan-based materials for biological applications were summarized and divided into the methods of extraction chitosan, the chemical modification of chitosan, chitosan-based materials for biological applications were described and discussed. Results: Chemical modification of chitosan broadens its applications, leading to developing numerous forms of chitosan-based materials with excellent properties. The excellent bioactivity of chitosan-based material enables it serves potential applications in biomedical fields. Conclusion: Chitosan-based materials not only exhibit the excellent activities of chitosan but also show other appealing performance of combined materials, even give the good synergistic properties of chitosan and its composite materials. Further studies are needed to define the ideal physicochemical properties of chitosan for each type of biomedical applications. The development of various functional chitosan-based materials for biological applications will be an important field of research, and this kind of material has important commercial value.

Compressible and elastic carbon aerogels with low density, excellent conductivity, high porosity, and chemical stability have attracted much attention in wearable energy storage and sensing devices...

The design and development of electrocatalysts composed of non-noble-metal catalysts with both large surface area and high electrical conductivities are crucial for the hydrogen evolution reaction (HER). Here, a xylose-based porous carbon is coupled with a MoS2−MoP heterojunction (MoS2−MoP/FPC) hybrid and used as a promising catalyst for HER. The hybrid is prepared by immobilizing petal-like MoS2 nanosheets on porous carbon (MoS2/FPC), followed by controlling the phosphidation in Ar/H2 to form MoS2−MoP/FPC. Red phosphorus provides the P species that can induce the construction of the heterojunction under the reducing atmosphere, along with the generation of a MoP phase and the splitting of the MoS2 phase. The as-prepared MoS2−MoP/FPC catalyst offers a low overpotential of 144 mV at a current density of 10 mA cm−2 and a small Tafel slope of 41 mV dec−1 for the HER in acidic media, as well as remarkable stability. Apart from the active nature of the hybrid, its outstanding activity is attributed to the MoS2−MoP heterojunction, and the good charge/mass-transfer ability of porous carbon. This strategy provides a new method to develop and design low-cost and high-performance catalysts for the HER.