Search

Presently, there have been some limitations in most of methods to determine poly (γ-glutamic acid) (γ-PGA) content because of many impurities in test specimens. It is necessary to establish a rapid and accurate method to quantify γ-PGA content. In this work, γ-PGA and some impurities commonly seen in fermented broth like glucose, glutamic acid and proteins were used to complex with copper ions. The results show that only γ-PGA can make copper ion precipitated, which content linearly correlates with the precipitate amount. From the study on the validity of the method, it is found that the accuracy and precision are 95.82% and 99.29%, much higher than the ones of method UV and weighing. Therefore, the method via the complexation of copper ion will be popularized to determine γ-PGA content in crude biological samples.

Tungsten oxide with strong acid resistance and weak O-binding ability could potentially achieve a tradeoff on the O-binding properties by constructing W and Ir dual sites for acidic oxygen evolution reaction (OER) catalysis. However, the peroxide intermediate formed during the OER process could react with tungsten oxide to produce soluble species, thereby severely limiting its application. Herein, we construct Ir–W@Ir–WO3−x core–shell nanoparticles with an Ir–W metallic core and an Ir-doped WO3−x (Ir–WO3−x) shell, which can deliver an impressive overpotential of 261 mV at 10 mA cm−2 for acidic OER catalysis and extraordinary catalytic stability. Spectroscopic analysis manifests that Ir–W@Ir–WO3−x could substantially suppress peroxide species formation and effectively avoid peroxide-induced corrosion during the OER process. Theoretical studies reveal that the moderate O-binding capability on Ir–W@Ir–WO3−x not only accelerates catalytic kinetics, but also restrains hydroperoxide formation. This work sheds light on the rational design of OER catalysts by modulating the adsorption behavior of oxygen-containing intermediates.

Summary Evaporation-condensation of red phosphorous to prepare phosphorous-based anodes inevitably generates white P residual, severely limiting its practical application due to the serious safety concern. Rather than removing the white P residual by complicated post-treatments, essentially prohibiting the generation of white P is a more meaningful alternative, but unfortunately it has been rarely studied so far. Herein, we demonstrate that the generation of white P can be substantially suppressed via sulfur-mediated phosphorous activation. Moreover, the prepared sulfur-doped P also exhibits the ever-reported fastest redox kinetics for sodium-ion storage. Electron spin resonance spectra and density functional theory calculations reveal that the introduced sulfur lives in the high-spin state during the evaporation-condensation process, which could activate P4 for polymerization. Meanwhile, sulfur-induced electron delocalization can also accelerate the Na-P redox kinetics. The capability to modulate phosphorus polymerization via the high-spin mediator could revolutionize the application of phosphorous for batteries and beyond.

pH-sensitive hydrogels have been applied in delivering probiotics and drugs. However, pH sensitivity has been found to be contradictory with structural stability in hydrogel preparation. In this work, a novel strategy based on two systems of sodium carboxymethyl cellulose (CMC)/chitosan (CS) and sodium alginate (SA)/calcium chloride was designed to construct a reticulated shell structure stable for 3 h in simulated gastric fluid (pH 1.2) but began to break up at 2 h in simulated intestinal fluid (pH 6.8), exhibiting obvious pH sensitivity. The embedding rate of Bacillus subtilis natto reached to 67.3%, and the sustained release lasted for more than 10 h. It is implicated that the reticulated shell structure has harmoniously balanced the two incompatible properties of pH sensitivity and sustained release of CMC/CS/SA beads.

Molybdenum disulfide is naturally inert for alkaline hydrogen evolution catalysis, due to its unfavorable water adsorption and dissociation feature originated from the unsuitable orbital orientation. Herein, we successfully endow molybdenum disulfide with exceptional alkaline hydrogen evolution capability by carbon-induced orbital modulation. The prepared carbon doped molybdenum disulfide displays an unprecedented overpotential of 45 mV at 10 mA cm−2, which is substantially lower than 228 mV of the molybdenum disulfide and also represents the best alkaline hydrogen evolution catalytic activity among the ever-reported molybdenum disulfide catalysts. Fine structural analysis indicates the electronic and coordination structures of molybdenum disulfide have been significantly changed with carbon incorporation. Moreover, theoretical calculation further reveals carbon doping could create empty 2p orbitals perpendicular to the basal plane, enabling energetically favorable water adsorption and dissociation. The concept of orbital modulation could offer a unique approach for the rational design of hydrogen evolution catalysts and beyond., Technologies allowing for sustainable hydrogen production will contribute to the decarbonization of the future energy supply. Here the authors report that carbon induced orbital modulation can facilitate the otherwise inert MoS2 electrocatalyst superior alkaline hydrogen evolution reactivity.

Recently, Li-O2 batteries have been considered to be promising next-generation energy storage devices owing to their high theoretical specific energy. However, due to the sluggish reaction kinetics of oxygen conversion, practical applications cannot achieve the desired results. By introducing vacancies in the MoS2 basal plane and using an in-situ synthesis method, we demonstrated the excellent catalysis of MoS2−x for oxygen redox kinetics, which can improve Li-O2 battery performance. The prepared MoS2−x displays little polarization, with a potential gap of 0.59 V and a high discharge capacity of 8,851 mA h g−1 at a current density of 500 mA g−1. The improved performance is mainly attributable to abundant S defects and plentiful diffusion channels in the MoS2−x/carbon 3D structural cathodes, which enable the adsorption of gaseous oxygen, reaction intermediates, and discharge products. To the best of our knowledge, these structures fabricated through 3D network design and surface modulation are among the best oxygen conversion catalysts developed so far, offering a new vista for the design of Li-O2 catalysts and beyond.

A porous chitosan (CS)/poly-(γ-glutamic acid) (γ-PGA) hydrogel was prepared by polymerization by electrostatic contacts of CS with γ-PGA without linker. The porosity of the hydrogel remarkably depends on γ-PGA content, pH regulator, and drying way. The optimization of them had given the hydrogel a high swelling capacity of 1398%, 11-fold higher than that of neat CS hydrogel. The hydrogel was applied to recover bovine serum albumin (BSA) from aqueous solution, and its adsorption capacity was influenced by the initial concentration and pH of BSA solution. Based on the studies of kinetics and isotherm, a high equilibrium adsorption capacity (qe = 948 mg/g) and a correlation coefficient of 0.996 were calculated from pseudo-second order kinetic equation, and a high affinitive constant (kF = 472 mL/mg) and a high saturated absorption capacity (qm = 1818.5 mg/g) were observed from Freundlich isotherm equation, indicating the porous hydrogel will be a good absorbent for protein recovery from sewage.

To study the effect of nattokinse (NK) on the synthesis of poly(γ-glutamic acid) (γ-PGA) in Bacillus subtilis natto. γ-PGA yield significantly decreased as NK was added in the original medium. With the increment of NK dosage, the yield decreased increasingly, but biomass increased instead of decreasing. The fact that cell density triggers the synthesis of γ-PGA is a controversial issue. γ-PGA yield and biomass closely correlate with addition time of NK. The later the addition of NK, the more γ-PGA yield decreased but the more biomass increased. It is concluded that cell hunger is a key factor to trigger the transmission of the cell density signal, and NK may inhibit γ-PGA synthesis by alleviating cell hunger. Besides, NK may reduce γ-PGA yield by degrading extracellular γ-PGA molecules. The study of adding L-glutamate of 0–20 g/L to the original medium showed that low concentration of L-glutamate (less than 5 g/L) could promote the synthesis of NK and γ-PGA, and thus NK may inhibit γ-PGA synthesis through strengthening substrate competition. NK mainly inhibits γ-PGA synthesis in Bacillus subtilis natto through alleviating cell starvation and strengthening substrate competition, and reduces γ-PGA yield through degrading extracellular γ-PGA molecules.

The HER activities of P-rich transition metal phosphides can be substantially boosted by N-induced lattice contraction., P-rich transition metal phosphides (TMPs) with abundant P sites have been predicted to be more favorable for hydrogen evolution reaction (HER) catalysis. However, the actual activities of P-rich TMPs do not behave as expected, and the underlying essence especially at the atomic level is also ambiguous. Our structural analysis reveals the inferior activity could stem from the reduced overlap of atomic wave functions between metal and P with the increase in P contents, which consequently results in too strong P-H interaction. To this end, we used N-induced lattice contraction to generally boost the HER catalysis of P-rich TMPs including CoP2, FeP2, NiP2, and MoP2. Refined structural characterization and theoretical analysis indicate the N-P strong interaction could increase the atomic wave function overlap and eventually modulate the H adsorption strength. The concept of lattice engineering offers a new vision for tuning the catalytic activities of P-rich TMPs and beyond.

Biopolymer-based hydrogel beads possessing intrinsic low-toxicity, biocompatibility and biodegradability have gained widespread utility in several applications. Among the biopolymers, cellulose is one of the most abundant renewable biomaterials. Herein cellulose hydrogel beads have been prepared by dissolving cellulose in 68% ZnCl2 solution and then crosslinking the polymer chains through calcium ions. The water and ethanol washing of the beads profoundly influences the beads architecture as characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray powder diffraction and Scanning electron microscopy. The total crystallinity index of the beads increases with the amount of calcium ions that is further enhanced by water washing. These beads, possessing a layer-like nanoporous structure, are capable of loading bovine serum albumin (BSA) and releasing in a sustained manner. The outcome promises a large-scale production of cellulose beads having the potential to be eco-friendly and inexpensive delivery carriers in food, pharmaceutical, medical and agriculture applications.

Building the fundamental relation between the polysulfides adsorption on cathode additives and Li S chemistry kinetics is critical for the rational design of efficient and reliable Li S batteries. Herein, we reveal that Li S chemistry kinetics can be well regulated by manipulating the electron-filling state of d orbitals in Ta2O5. The prepared S@N-Ta2O5/rGO with moderate N contents delivers the lowest polarization for LiPSs conversion and the highest specific capacity of 1252.8 mAh g−1 at 0.2C. More importantly, the theoretical analysis unravel that the enhanced electrochemical performance is mainly originated from the orbital-induced adsorption modulation. This work could offer a powerful platform to manipulate the Li S chemistry by orbital engineering for high-performance Li S batteries.

Water electrolysis is considered as a promising sustainable technology to produce hydrogen thereby reducing dependence on fossil fuels. The oxygen evolution reaction (OER), a half reaction of water electrolysis is hampered by its slow kinetics. Developing high performance electrocatalysts for enhancing OER kinetics is the main bottleneck of this technology. In this study, we synthesize a ternary cobalt iron disulfide as a pre-catalyst for OER. After the activation step, the synthesized catalyst transformed to cobalt-iron amorphous oxide with oxygen defects as an efficient catalyst for OER. At its optimized Co/Fe ratio, equal to 3:1, the activated catalyst requires only 267 mV overpotential to reach the current density of 10 mA cm−2, while Tafel slope is 34 mV dec-1. Density functional theory calculation reveals that the active phase of the OER process is a thin layer of oxide that forms during the voltammetry activating process and the reduced energy barrier of rate determining step contributes to the excellent OER performance of cobalt-iron amorphous oxide.

Here we report the synthesis of Co/Co9S8 core-shell structures anchored onto S, N co-doped porous graphene sheets (Co/Co9S8@SNGS) from thiophene-2,5-dicarboxylate (Tdc) and 4,4ˊ-bipyridine (Bpy) dual organic ligands assembled Co-based metal-organic frameworks (Co-MOFs) in situ grown on graphene oxide sheets (Co-MOFs@GO) by a room-temperature solution reaction. S-containing Tdc and N-containing Bpy not only trigger the growth of Co-MOFs nanocrystals with a fixed S/N atomic ratio of 1:2.4 on GO sheets in the presence of Co2+ in H2O/NaOH system, but also provide S, N doping sources in the pyrolysis process of Co-MOFs to form Co/Co9S8 core-shell structure and S, N co-doping in graphene. The results demonstrate that the obtained Co/Co9S8@SNGS at 1000 °C (Co/Co9S8@SNGS-1000) by pyrolysis of Co-MOFs@GO exhibits superiorly bifunctional catalytic activities of the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in 0.1 M KOH electrolyte, affording an overpotential of 290 mV for OER at a current density of 10 mA cm−2 and 350 mV for HER at a current density of 20 mA cm−2. The OER activity of Co/Co9S8@SNGS-1000 is slightly better than that of commercial RuO2 catalyst, simultaneously, Co/Co9S8@SNGS-1000 also exhibits good HER activity. As electrode material for full water splitting in 0.1 M KOH solution, the Co/Co9S8@SNGS-1000 electrodes exhibit O2 and H2 generation efficiencies of 2.48 and 4.87 μmol min−1 respectively, at an applied potential of 1.58 V (vs. RHE) under the given time range, affording nearly 100% Faradaic yield during electrocatalytic water splitting to produce O2 and H2.

The facet-dependent photocatalytic performance of TiO2 nanocrystals has been extensively investigated due to their promising applications in renewable energy and environmental fields. However, the intrinsic distinction in the photocatalytic oxidation activities between the {001} and {101} facets of anatase TiO2 nanocrystals is still unclear and under debate. In this work, a simple photoelectrochemical method was employed to meaningfully quantify the intrinsic photocatalytic activities of {001} and {101} faceted TiO2 nanocrystal photoanodes. The effective surface areas of photoanodes with different facets were measured based on the monolayer adsorption of phthalic acid on TiO2 photoanode surface by an ex situ photoelectrochemical method, which were used to normalize the photocurrents obtained from different faceted photoanodes for meaningful comparison of their photocatalytic activities. The results demonstrated that the {001} facets of anatase TiO2 nanocrystals exhibited much better photocatalytic activity than that of {101} facets of anatase TiO2 nanocrystals toward photocatalytic oxidation of water and organic compounds with different functional groups (e.g., –OH, –CHO, –COOH). Furthermore, the instantaneous kinetic constants of photocatalytic oxidation of pre-adsorbates on {001} faceted anatase TiO2 photoanode are obviously greater than those obtained at {101} faceted anatase TiO2 photoanode, further verifying the higher photocatalytic activity of {001} facets of anatase TiO2. This work provided a facile photoelectrochemical method to quantitatively determine the photocatalytic oxidation activity of specific exposed crystal facets of a photocatalyst, which would be helpful to uncover and meaningfully compare the intrinsic photocatalytic activities of different exposed crystal facets of a photocatalyst.

Electrocatalysts with high catalytic activity and stability play a key role in promising renewable energy technologies, such as fuel cells and metal-air batteries. Here, we report the synthesis of Fe/Fe2O3 nanoparticles anchored on Fe-N-doped carbon nanosheets (Fe/Fe2O3@Fe-N-C) using shrimp shell-derived N-doped carbon nanodots as carbon and nitrogen sources in the presence of FeCl3 by a simple pyrolysis approach. Fe/Fe2O3@Fe-N-C obtained at a pyrolysis temperature of 1,000 °C (Fe/Fe2O3@Fe-N-C-1000) possessed a mesoporous structure and high surface area of 747.3 m2·g−1. As an electrocatalyst, Fe/Fe2O3@Fe-N-C-1000 exhibited bifunctional electrocatalytic activities toward the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline media, comparable to that of commercial Pt/C for ORR and RuO2 for OER, respectively. The Zn-air battery test demonstrated that Fe/Fe2O3@Fe-N-C-1000 had a superior rechargeable performance and cycling stability as an air cathode material with an open circuit voltage of 1.47 V (vs. Ag/AgCl) and a power density of 193 mW·cm−2 at a current density of 220 mA·cm−2. These performances were better than other commercial catalysts with an open circuit voltage of 1.36 V and a power density of 173 mW·cm−2 at a current density of 220 mA·cm−2 (a mixture of commercial Pt/C and RuO2 with a mass ratio of 1:1 was used for the rechargeable Zn-air battery measurements). This work will be helpful to design and develop low-cost and abundant bifunctional oxygen electrocatalysts for future metal-air batteries.

Development of cheap, abundant and metal-free N-doped carbon materials as high efficiency oxygen reduction electrocatalysts is crucial for their practical applications in future fuel cell devices. Here, three-dimensional (3D) N-doped porous carbon (NPC) materials have been successfully developed by a simple template-assisted (e.g., SiO2 spheres) high temperature pyrolysis approach using shrimp-shell derived N-doped carbon nanodots (N-CNs) as carbon and nitrogen sources obtained through a facile hydrothermal method. The shrimp-shell derived N-CNs with a product yield of ∼ 5% possess rich surface O- and N-containing functional groups and small nanodot sizes of 1.5-5.0 nm, which are mixed with surface acidification treated SiO2 spheres with an average diameter of ∼ 200 nm in aqueous solution to form a N-CNs@SiO2 composite subjected to a thermal evaporation treatment. The resultant N-CNs@SiO2 composite is further thermally treated in a N2 atmosphere at different pyrolysis temperatures, followed by acid etching, to obtain 3D N-doped porous carbon (NPC) materials. As electrocatalysts for oxygen reduction reaction (ORR) in alkaline media, the experimental results demonstrate that 3D NPC obtained at 800 °C (NPC-800) with a surface area of 360.2 m(2) g(-1) exhibits the best ORR catalytic activity with an onset potential of -0.06 V, a half wave potential of -0.21 V and a large limiting current density of 5.3 mA cm(-2) (at -0.4 V, vs. Ag/AgCl) among all NPC materials investigated, comparable to that of the commercial Pt/C catalyst with an onset potential of -0.03 V, a half wave potential of -0.17 V and a limiting current density of 5.5 mA cm(-2) at -0.4 V. Such a 3D porous carbon ORR electrocatalyst also displays superior durability and high methanol tolerance in alkaline media, apparently better than the commercial Pt/C catalyst. The findings of this work would be valuable for the development of low-cost and abundant N-doped carbon materials from biomass as high performance metal-free electrocatalysts.

In this work, shrimp-shell derived N-doped carbon nanodots (N-CNs) as carbon and nitrogen sources are assembled into particle-like aggregates by a simple polymerization reaction of pyrrole in the presence of Fe3+ to form Fe containing N-CN/polypyrrole (PPY) composites (Fe–N-CN/PPy). The resulting composites are thermally treated by a facile pyrolysis approach under a N2 atmosphere to obtain an Fe,N-doped porous graphitic carbon (Fe-N-PGC) material. The results demonstrate that the pyrolytically converted carbon material at 800 °C (Fe-N-PGC-800) exhibits an approximately mesoporous structure with a pore size distribution centered at ∼1.97 nm and ∼2.8 nm and a surface area of 806.7 m2 g−1. As an electrocatalyst for oxygen reduction reaction (ORR) in alkaline media, Fe-N-PGC-800 shows superior ORR catalytic activity with an onset potential of −0.017 V and a limiting current density of 5.42 mA cm−2 (at −0.4 V, vs. Ag/AgCl), which is superior to that of commercial Pt/C catalysts (onset potential of −0.018 V and a limiting current density of 5.21 mA cm−2 at −0.4 V, vs. Ag/AgCl). Additionally, Fe-N-PGC-800 also exhibits good ORR activity in acidic media with an onset potential of 0.53 V and a limiting current density of 5.58 mA cm−2 (at 0.1 V, vs. Ag/AgCl), comparable to that of most reported Fe-based N-doped carbon electrocatalysts. An air cathode made from Fe-N-PGC-800 shows high performance and superior cycling durability in zinc–air batteries (gravimetric energy density of 752 Wh kg−1), comparable to that of commercial Pt/C-based batteries (gravimetric energy density of 774 Wh kg−1). This work demonstrates the feasibility of utilizing biomass as a starting material to fabricate Fe,N-doped carbon materials as high performance ORR electrocatalysts for practical application in ORR-relevant energy devices.

Two-dimensional (2D) materials such as graphene and transition-metal dichalcogenides reveal the electronic phases that emerge when a bulk crystal is reduced to a monolayer1-4. Transition-metal oxide perovskites host a variety of correlated electronic phases5-12, so similar behaviour in monolayer materials based on transition-metal oxide perovskites would open the door to a rich spectrum of exotic 2D correlated phases that have not yet been explored. Here we report the fabrication of freestanding perovskite films with high crystalline quality almost down to a single unit cell. Using a recently developed method based on water-soluble Sr3Al2O6 as the sacrificial buffer layer13,14 we synthesize freestanding SrTiO3 and BiFeO3 ultrathin films by reactive molecular beam epitaxy and transfer them to diverse substrates, in particular crystalline silicon wafers and holey carbon films. We find that freestanding BiFeO3 films exhibit unexpected and giant tetragonality and polarization when approaching the 2D limit. Our results demonstrate the absence of a critical thickness for stabilizing the crystalline order in the freestanding ultrathin oxide films. The ability to synthesize and transfer crystalline freestanding perovskite films without any thickness limitation onto any desired substrate creates opportunities for research into 2D correlated phases and interfacial phenomena that have not previously been technically possible.

Creating oxide interfaces with precise chemical specificity at the atomic layer level is desired for the engineering of quantum phases and electronic applications, but highly challenging, owing partially to the lack of in situ tools to monitor the chemical composition and completeness of the surface layer during growth. Here we report the in situ observation of atomic layer-by-layer inner potential variations by analysing the Kikuchi lines during epitaxial growth of strontium titanate, providing a powerful real-time technique to monitor and control the chemical composition during growth. A model combining the effects of mean inner potential and step edge density (roughness) reveals the underlying mechanism of the complex and previously not well-understood reflection high-energy electron diffraction oscillations observed in the shuttered growth of oxide films. General rules are proposed to guide the synthesis of atomically and chemically sharp oxide interfaces, opening up vast opportunities for the exploration of intriguing quantum phenomena at oxide interfaces., Precisely controlled growth of oxide interfaces at the atomic layer level is critical for device applications but quite challenging. Here Sun et al. show real time monitoring and control of the surface composition of epitaxial strontium titanate perovskite films by analysing the Kikuchi lines.

A series of novel composites g -C 3 N 4 /SnO 2 were first synthesized using a facile two-step process. Through systematic sample characterization, it is demonstrated that all composites consist of two components: g -C 3 N 4 with a low specific surface area and SnO 2 nanoparticles with a large specific surface area. Within the composites, component of SnO 2 nanoparticles dispersed well onto the component g -C 3 N 4 with a clear interface between each other. The interactions between both components are strong, as confirmed by variations in binding energies and lattice parameters. A synergistic collaboration is achieved for the composites, as contributed by surface adsorption of organics from π–π conjugation of component g -C 3 N 4 , improved separation efficiency of photo-generated carriers from interfacial interactions between both components, and increased surface area from component SnO 2 nanoparticles. As a consequence, these composites exhibit a significantly enhanced photocatalytic activity towards MO degradation under visible light irradiation. The optimum photocatalytic performance is achieved at 47.5 wt% SnO 2 , showing a reaction kinetic constant of 0.0078, which is much higher than those of components g -C 3 N 4 and SnO 2 . With the unique synergistic collaboration, the optimized composite with Pt additives is also successfully applied to high-efficiency production of hydrogen from water splitting under visible light irradiation.

This work gives a first report on the effective visible-light-driven photocatalyst of brookite TiO2 (br-TiO2) hybridized with g-C3N4. This hybrid was prepared via a facile calcination in air. When irradiated under visible light, all br-TiO2/g-C3N4 hybrids showed an activity superior to the component g-C3N4 or br-TiO2 in methyl orange (MO) degradation. The optimum photocatalytic activity of the hybrid br-TiO2/g-C3N4 is higher than those of other types of TiO2 (anatase and rutile) when hybridized with g-C3N4. Furthermore, the optimized hybrid, br-TiO2/g-C3N4 (35 wt%), was successfully applied to toxic As3+ oxidation and water splitting for hydrogen generation under visible light. All these results clearly demonstrate that the hybridization of br-TiO2 with g-C3N4 is highly promising for photocatalytic uses, which are barely accessible in previous literature. This abnormal observation is ascribed to the effective separation of the photo-generated carriers on the surfaces between the closely contacted br-TiO2 and g-C3N4.

Currently, it is in urgent need to develop novel selective PDE4 inhibitors with novel structural scaffolds to overcome the adverse effects and improve the efficacy. Novel 1-phenyl-3,4-dihydroisoquinoline amide derivatives were developed as potential PDE4 inhibitors based on the structure-based drug design and fragment identification strategy. A SARs analysis was performed in substituents attached in the C-3 side chain phenyl ring, indicating that the attachment of methoxy group or halogen atom substitution at the ortho-position of the phenyl ring was helpful to enhance both inhibitory activity toward PDE4B and selectivity. Compound 15 with excellent selectivity, exhibited the most potent inhibition in vitro and in vivo, which is a promising lead for development of a new class of selective PDE4 inhibitors.

Co/CoO nanoparticles immobilized on Co–N-doped carbon were successfully developed using shrimp-shell derived N-doped carbon nanodots as precursors by a combined approach of polymerization and pyrolysis, as electrocatalysts exhibiting trifunctional catalytic activities toward oxygen reduction, oxygen evolution and hydrogen evolution reactions and high performance in rechargeable zinc–air batteries.

The carbon-coated Li4Ti5O12 mesoporous nanoparticles were directly synthesized by a facile solvothermal method with a subsequent N2 treatment. The resultant Li4Ti5O12 did not show any by-products of TiN or TiC, but a unique mesoporous structure and particle dimension of about 20 nm. Confined to the surface thin layer