Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 31
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Nanomaterials (Basel) ; 14(6)2024 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-38535697

RESUMEN

Formic acid has emerged as a highly promising hydrogen storage material, and the development of efficient catalysts to facilitate its dehydrogenation remains imperative. In this study, a novel catalyst consisting of palladium nanoparticles supported on boron-doped porous carbon (Pd/BPC) was successfully synthesized to enable efficient hydrogen production through the dehydrogenation of formic acid. The impacts of the boron doping ratio, doping temperature, and palladium reduction temperature on the catalyst's performance were systemically investigated. The results demonstrated the Pd/BPC catalyst synthesized with a carbon-to-boron ratio of 1:5 by calcination at 900 °C and subsequent reduction at 60 °C exhibited superior formic acid dehydrogenation performance, being 2.9 and 3.8 times greater than that of the Pd/PC catalysts without boron doping and commercial Pd/C, respectively. Additionally, the catalyst showed excellent cycle stability with no significant activity reduction after five consecutive cycles. Experimental and theoretical results reveal that boron doping not only facilitates the homogenous distribution of Pd nanoparticles but also induces a stronger support-metal interaction, thereby reinforcing the catalytic performance. This research is expected to provide valuable insights into the economically viable and efficient production of environmentally friendly hydrogen energy.

2.
J Colloid Interface Sci ; 662: 516-526, 2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38364476

RESUMEN

Constructing high-performance and low-cost carbon anodes for potassium-ion batteries (PIBs) is highly desirable but faces great challenges. In this study, we present a novel approach to fabricating N/S co-doped hollow amorphous carbon (LNSHAC) for superior potassium storage through a template-assisted molecular structure regulation strategy. By tailoring a 3D crosslinked aromatics precursor from fluid catalytic cracking slurry (FCCs), the LNSHAC features a N/S co-doped hollow structure with enlarged interlayer spacing of up to 0.405 nm and rich defects. Such unique microstructure offers fast transport channels for K-ion intercalation/deintercalation and provides more active sites, leading to boosted reaction kinetics and potassium storage capacity. Consequently, the LNSHAC electrode delivers an impressive reversible capacity (466.2 mAh g-1 at 0.1 A/g), excellent rate capability (336.3 mAh g-1 at 2 A/g), and superior cyclic performance (256.9 mAh g-1 after 5000 cycles at 5 A/g with admirable retention of 76.9 %), standing out among the reported carbon-based anodes. When KFeHCF is employed as the cathode, the LNSHAC-based K-ion full cell exhibits a high reversible capacity of 176.6 mAh g-1 at 0.1 A/g and excellent cyclic stability over 200 cycles. This work will inspire the development and application of advanced carbon-based materials for potassium electrochemical energy storage.

3.
Phys Chem Chem Phys ; 26(3): 2249-2259, 2024 Jan 17.
Artículo en Inglés | MEDLINE | ID: mdl-38165279

RESUMEN

Lithium-sulfur batteries (LSBs) are one of the most promising energy storage devices with high energy density. However, their application and commercialization are hampered by the slow Li-S redox chemistry. Fe0.875M0.125S2 (M = Ti, V), as the sulfur cathode host, enhances the Li-S redox chemistry. FeS2 with Pa3̄ is transformed into Li2FeS2 with P3̄m1 after discharge. The structure changes and physicochemical properties during Fe0.875M0.125S2 discharge process are further investigated to screen out the sulfur cathode host materials with the best comprehensive properties. The discharge structure of Fe0.875M0.125S2 is verified by the thermodynamic stability of Li-deficient phases, voltage and capacity based on Monte Carlo methods. Fe0.875M0.125S2 with Pa3̄ is transformed into Li2Fe0.875M0.125S2 with P3̄m1 after discharge. Using the first-principles calculations, the physicochemical properties of Li2Fe0.875M0.125S2 are systematically investigated, including the formation energy, voltage, theoretical capacity, electrical conductivity, Li+ diffusion, catalytic performance and Li2S oxidation decomposition. The average redox voltage of Li2Fe0.875V0.125S2 is higher than that of Li2Fe0.875Ti0.125S2. Li2Fe0.875M0.125S2 shows metallic properties. Li2Fe0.875V0.125S2 is more beneficial to the reduction reaction of Li2S2 and Li2S oxidation decomposition. Fe0.875V0.125S2 has more potential as the sulfur cathode host than Fe0.875Ti0.125S2 in LSBs. A new strategy for the selection of the sulfur cathode host material for LSBs is provided by this work.

4.
Adv Sci (Weinh) ; 11(12): e2306599, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38224212

RESUMEN

Developing efficient metal-nitrogen-carbon (M-N-C) single-atom catalysts for oxygen reduction reaction (ORR) is significant for the widespread implementation of Zn-air batteries, while the synergic design of the matrix microstructure and coordination environment of metal centers remains challenges. Herein, a novel salt effect-induced strategy is proposed to engineer N and P coordinated atomically dispersed Fe atoms with extra-axial Cl on interlinked porous carbon nanosheets, achieving a superior single-atom Fe catalyst (denoted as Fe-NP-Cl-C) for ORR and Zn-air batteries. The hierarchical porous nanosheet architecture can provide rapid mass/electron transfer channels and facilitate the exposure of active sites. Experiments and density functional theory (DFT) calculations reveal the distinctive Fe-N2P2-Cl active sites afford significantly reduced energy barriers and promoted reaction kinetics for ORR. Consequently, the Fe-NP-Cl-C catalyst exhibits distinguished ORR performance with a half-wave potential (E1/2) of 0.92 V and excellent stability. Remarkably, the assembled Zn-air battery based on Fe-NP-Cl-C delivers an extremely high peak power density of 260 mW cm-2 and a large specific capacity of 812 mA h g-1, outperforming the commercial Pt/C and most reported congeneric catalysts. This study offers a new perspective on structural optimization and coordination engineering of single-atom catalysts for efficient oxygen electrocatalysis and energy conversion devices.

5.
iScience ; 26(8): 107419, 2023 Aug 18.
Artículo en Inglés | MEDLINE | ID: mdl-37575181

RESUMEN

In birds, little is known about how individuals choose nest sites based on their personality traits. Here, we investigate whether a female's personality (activity and breathing rate) can affect patterns of nest site selection at different spatial scales in a wild population of chestnut thrush (Turdus rubrocanus) and determine whether nest site characteristics and female personality traits affect clutch size and nest success during incubation. We found that neither activity nor breathing rate were associated with large-scale nesting habitat variables. At the fine-scale level, more active females chose nest sites with greater nest lateral concealment. Females with higher breathing rates laid smaller clutch sizes than individuals with lower breathing rates. Nests of females with lower breathing rate had higher nest success during incubation. This work highlights the relationships between personality and nest site selection in birds, and the important role of female personality traits in reproductive success.

6.
J Colloid Interface Sci ; 633: 1022-1032, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36516678

RESUMEN

Heteroatom-doped carbon materials have been regarded as sustainable alternatives to the noble-metal catalysts for oxygen reduction reaction (ORR), while the catalytic performances still remain unsatisfactory. Herein, we develop a metal-free adjacent N, P and S-codoped hierarchical porous carbon nanoshells (NPS-HPCNs) through a novel layer-by-layer template coating method. The NPS-HPCNs is rationally fabricated by crosslinking of polyethyenemine (PEI) and phytic acid (PA) on nano-SiO2 template surface and subsequently coating of viscous sulfur-bearing petroleum pitch, followed by pyrolysis and alkaline etching. Soft X-ray absorption near-edge spectroscopy (XANES) analysis and density functional theory (DFT) calculations prove the engineering of adjacent N, P and S atoms to generate synergistic and reinforced active sites for oxygen electrocatalysis. The NPS-HPCNs manifests excellent ORR activity with a half-wave potential (E1/2) of 0.86 V, as well as promoted durability and methanol tolerance in alkaline medium. Remarkably, the NPS-HPCNs-based Zn-air battery delivers an open-circuit voltage of 1.479 V, a considerable peak power density of 206 mW cm-2 and robust cycling stability (over 200 h), even exceeding the commercial Pt/C catalyst. This study offers fundamental insights into the construction and synergistic mechanism of adjacent heteroatoms on carbon substrate, providing advanced metal-free electrocatalysts for Zn-air batteries and other energy conversion and storage devices.

7.
J Colloid Interface Sci ; 634: 972-982, 2023 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-36571859

RESUMEN

Photo-Fenton-like catalysis allows development of novel advanced oxidation technology with promising application in wastewater treatment. In this work, carbon dots (CDs) were intercalated between CuO nanoparticles and coralloid flower-like graphitic carbon nitride (g-C3N4) to fabricate a ternary CuO/CDs/g-C3N4 hybrid for synergetic visible-light-driven photo-Fenton-like oxidation. The CuO/CDs/g-C3N4 hybrid showed remarkable degradation efficiency towards recalcitrant organic contamination, excellent tolerance to realistic environmental conditions, exceptional stability and wide universality, declaring great potential for practical applications. •OH and •O2- radicals were demonstrated to be the primary contributors in the photo-Fenton-like system. Mechanism studies reveal dual charge transfer pathways in the Z-scheme CuO/g-C3N4 heterojunction assisted by interfacial electron transmission bridges of CDs, which can simultaneously boost the reduction of Cu2+ to Cu+ in the Fenton-like cycle and accelerate the Z-scheme electron flow from CuO to g-C3N4, leading to synergistic enhancement of the catalytic performance. This work would afford a feasible strategy to develop reinforced solar energy-assisted photo-Fenton-like catalysis systems for water remediation.

8.
Foods ; 11(21)2022 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-36360021

RESUMEN

This study investigated the changes in the structure and properties of soybean protein after hydrolysis using two types of hybrid nanoflowers (alcalase@Cu3(PO4)2•3H2O (ACHNs) and dispase@Cu3(PO4)2•3H2O (DCHNs)) and examined the basic properties and oxidative stability of hydrolyzed soybean protein emulsions. The formations of the two hybrid nanoflowers were first determined using a scanning electron microscope, transmission electron microscope, and Fourier infrared spectroscopy. The structure and functional properties of soybean protein treated with hybrid nanoflowers were then characterized. The results indicated that the degree of hydrolysis (DH) of the ACHNs hydrolysates was higher than that of the DCHNs for an identical reaction time. Soybean protein hydrolysates treated with two hybrid nanoflowers showed different fluorescence and circular dichroism spectra. The solubility of the hydrolysates was significantly higher (p < 0.05) than that of the soybean protein (SPI) at all pH values tested (2.0−10.0)*: at the same pH value, the maximum solubility of ACHNs hydrolysates and DCHNs hydrolysates was increased by 46.2% and 42.2%, respectively. In addition, the ACHNs hydrolysates showed the highest antioxidant activity (DPPH IC50 = 0.553 ± 0.009 mg/mL, ABTS IC50 = 0.219 ± 0.019 mg/mL, and Fe2+ chelating activity IC50 = 40.947 ± 3.685 µg/mL). The emulsifying activity index of ACHNs and DCHNs hydrolysates reached its maximum after hydrolysis for 120 min at 61.38 ± 0.025 m2/g and 54.73 ± 0.75 m2/g, respectively. It was concluded that the two hydrolysates have better solubility and antioxidant properties, which provides a theoretical basis for SPI product development. More importantly, the basic properties and oxidative stability of the soybean-protein-hydrolysates oil-in-water emulsions were improved. These results show the importance of proteins hydrolyzed by hybrid nanoflowers as emulsifiers and antioxidants in the food and pharmaceutical industry.

9.
J Colloid Interface Sci ; 623: 9-20, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-35561576

RESUMEN

Visible light-driven photo-Fenton-like technology is a promising advanced oxidation process for water remediation, while the construction of effective synergetic system remains a great challenge. Herein, iron hydroxide oxide (α-FeOOH) with controllable oxygen vacancy defects were engineered on reduced graphene oxide (rGO) nanosheets (named as OVs-FeOOH/rGO) through an in-situ redox method for boosting visible light-driven photo-Fenton-like oxidation. By adjusting the pH environment to modulate the redox reaction kinetics between graphene oxide (GO) and ferrous salt precursors, the oxygen vacancy concentration in α-FeOOH could be precisely controlled. With optimized oxygen vacancy defects obtained at pH 5, the OVs-FeOOH/rGO displayed superior photo-Fenton-like performance for Rhodamine B degradation (99% within 40 mins, rate constant of 0.2278 mg-1 L min-1) with low H2O2 dosage (5 mM), standing out among the reported photo-Fenton-like catalysts. The catalyst also showed excellent reusability, general applicability, and tolerance ability of realistic environmental conditions, which demonstrates great potential for practical applications. The results reveal that moderate oxygen vacancy defects can not only strengthen absorption of visible light and organic pollutants, but also promote the charge transfer to simultaneously accelerate the photogenerated electron-hole separation and Fe(III)/Fe(II) Fenton cycle, leading to the remarkable photo-Fenton-like oxidation performance. This work sheds light on the controllable synthesis and mechanism of oxygen vacancy defects to develop efficient photo-Fenton-like catalysts for wastewater treatment.


Asunto(s)
Compuestos Férricos , Peróxido de Hidrógeno , Catálisis , Grafito , Hidróxidos , Hierro , Luz , Oxidación-Reducción , Oxígeno
10.
Small ; 17(31): e2102178, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-34196493

RESUMEN

Enzyme-mimicking nanomaterials for antioxidative therapy is a promising star to treat more than 200 diseases or control their progressions through scavenging excessive reactive oxygen species (ROS), such as O2•- and H2 O2 . However, they can inversely produce stronger ROS (e.g., •OH) under many disease conditions (e.g., low pH for myocardial ischemia). Herein, a biocompatible -Cu-O-Zn- bimetallic covalent doped carbon dots (CuZn-CDs) processing both catalase (CAT) and superoxide dismutase activities are reported, mainly because of their abundant electrons and the excellent electron transfer abilities. In addition, Cu dopant helps to balance the positive charge at Zn dopant resulting from low pH, enabling CuZn-CDs to still process CAT ability rather than peroxidase ability. Benefiting from it, CuZn-CDs exhibit sufficient in vitro ROS scavenging ability and cardiomyocyte protective effect against ROS-induced damage. In vivo results further demonstrate that CuZn-CDs can protect the heart from ischemia-reperfusion injury. In addition to antioxidative therapy, the rapid renal clearance and low toxicity properties of CuZn-CDs in animal model reveal high biocompatibility which will facilitate clinical use.


Asunto(s)
Antioxidantes , Carbono , Animales , Catalasa , Electrones , Superóxido Dismutasa , Zinc
11.
J Colloid Interface Sci ; 587: 810-819, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33248699

RESUMEN

Massive production of efficient, durable, and low-cost electrocatalysts toward oxygen reduction reaction (ORR) is urgently desired for the development of energy storage and conversion devices. In this study, a facile and cost-effective strategy is proposed for the scalable synthesis of atomically dispersed FeNC derived from petroleum asphalt (FeNC@PA) as a reinforced catalyst for ORR. The FeNC@PA is fabricated through a layer-by-layer cladding template and subsequent pyrolysis method. Intercalating appropriate amount of petroleum asphalt not only improves the graphitic degree to reinforce the atomic Fe-Nx active sites, but also increases mass yield of the catalyst (~220%) compared with the FeNC counterpart. Serving as an ORR electrocatalyst, the optimized FeNC@PA-1:4 provides almost a four-electron transfer pathway (3.96) and exhibits superior electrocatalytic activity with a half-wave potential (E1/2) of 0.90 V to the commercial Pt/C catalyst (E1/2 = 0.86 V), as well as promoted durability and methanol tolerance in alkaline medium. Moreover, the zinc-air battery based on FeNC@PA-1:4 cathode delivers a high power density of 166.7 mW cm-2. This work may help the massive production of robust atomically dispersed non-noble metal catalysts for ORR and provide a new avenue for the high value-added utilization of petroleum asphalt.

12.
Small ; 16(51): e2004631, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33251705

RESUMEN

Lithium-sulfur (Li-S) batteries are facing a significant barrier due to the diffusion of intermediate redox species. Although some S doped covalent framework cathodes have been reported with outstanding reversibility, the low content of sulfur (less than 30%) limits the practical applications. To overcome the issue, the sulfur and nitrogen co-doped covalent compounds (S-NC) as a host-type cathode have been developed through the radical transfer process during thermal cracking amino groups on the precursor, and then plentiful positively charged sulfur radicals can be controllably introduced. The experimental characterization and DFT theoretical calculation certificate that the sulfur radicals in S-NC/S can expedite redox reactions of intermediate polysulfides to impede their dissolution. Moreover, the energy barriers during ions transfer also obviously decreased after introducing S radicals, which lead to improved rate performance.

13.
Food Funct ; 11(11): 10205-10218, 2020 Nov 18.
Artículo en Inglés | MEDLINE | ID: mdl-33166374

RESUMEN

This study investigated the stability and the in vitro digestion of curcumin nanoemulsions stabilized by three protein hydrolysates: peanut protein isolate (PPI), soybean protein isolate (SPI) and whey protein isolate (WPI). After enzymatic hydrolysis, the protein structure became more disordered, and increased antioxidant capacity was also observed for protein hydrolysates. The protein hydrolysates generated curcumin nanoemulsions with considerable stability over 28 days of storage. Moreover, protein hydrolysates more effectively improved the lipolysis rate and bioaccessibility of curcumin nanoemulsions than native proteins, and PPI hydrolysates exhibited the highest lipolysis rate (110.43%) and the highest bioaccessibility (53.24%). This study indicated that protein hydrolysates could be used as emulsifiers for preparing nanoemulsion delivery systems with high stability and bioaccessibility.


Asunto(s)
Antioxidantes/química , Arachis/química , Curcumina/química , Portadores de Fármacos/química , Proteínas de Plantas/química , Proteína de Suero de Leche/química , Composición de Medicamentos , Estabilidad de Medicamentos , Emulsionantes/química , Hidrolisados de Proteína/química , Proteínas de Soja/química
14.
Ecol Evol ; 10(14): 7006-7020, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32760508

RESUMEN

Dispersal affects the spatial distribution and population structure of species. Dispersal is often male-biased in mammals while female-biased in birds, with the notable exception of the Anatidae. In this study, we tested genetic evidence for sex-biased dispersal (SBD) in the Swan Goose Anser cygnoides, an Asian endemic and IUCN vulnerable species, which has been increasingly restricted to breeding on Mongolian steppe wetlands. We analyzed the genotypes of 278 Swan Geese samples from 14 locations at 14 microsatellite loci. Results from assignment indices, analysis of molecular variance, and five other population descriptors all failed to support significant SBD signals for the Swan Goose at the landscape level. Although overall results showed significantly high relatedness within colonies (suggesting high levels of philopatry in both sexes), local male genetic structure at the 1,050 km distance indicated greater dispersal distance for females from the eastern sector of the breeding range. Hence, local dispersal is likely scale-dependent and female-biased within the eastern breeding range. These findings are intriguing considering the prevailing expectation for there to be female fidelity in most goose species. We suggest that while behavior-related traits may have facilitated the local genetic structure for the Swan Goose, several extrinsic factors, including the decreasing availability of the nesting sites and the severe fragmentation of breeding habitats, could have contributed to the absence of SBD at the landscape level. The long-distance molt migration that is typical of goose species such as the Swan Goose may also have hampered our ability to detect SBD. Hence, we urge further genetic sampling from other areas in summer to extend our results, complemented by field observations to confirm our DNA analysis conclusions about sex-specific dispersal patterns at different spatial scales in this species.

15.
Food Chem ; 330: 127215, 2020 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-32534158

RESUMEN

This study investigated changes of the structure and emulsifying properties of peanut protein isolate (PPI) during multiple freeze-thaw (F-T) cycles. According to the Fourier transform infrared spectrum, the F-T treatment to PPI reduced the content of protein ordered structure significantly. The result of fluorescence spectrum revealed that the polarity of PPI surroundings first increased and then decreased. Similarly, the free sulfhydryl content and surface hydrophobicity of PPI increased firstly and decreased. However, the carbonyl content and particle size of PPI increased continuously after F-T treatment. The emulsification performance of PPI after F-T treatment was significantly improved. The emulsion prepared by PPI after 3 F-T cycles had the smallest mean particle size, the highest absolute value of zeta-potential and the most uniform microstructure distribution, showed the best performance of emulsifying ability. Therefore, it can be known that F-T cycles treatment could effectively change protein structure and improve protein emulsifying properties.


Asunto(s)
Arachis/química , Proteínas de Plantas/química , Emulsiones/química , Congelación , Interacciones Hidrofóbicas e Hidrofílicas , Tamaño de la Partícula
16.
Int J Biol Macromol ; 142: 658-667, 2020 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-31622709

RESUMEN

In this study, the oil-in-water nanoemulsions were prepared by 3% (v/v) MCT oil phase (containing 10 mg/mL curcumin) with 3% (v/v) ß-conglycinin hydrolysates (7SH) and 3% (v/v) ß-conglycinin-DX-40 conjugates (7SD) as the emulsifiers. In order to explore the effect of enzyme hydrolysis and glycosylation on the nanoemulsions stability, the native ß-conglycinin (7S) (3%, v/v) was used as control. The average droplet size of 7SH-stabilized nanoemulsions decreased from degree of hydrolysis (DH) 3%-12%, but then increased after 12%, which revealed that limited enzymolysis should be selected for nanoemulsion preparation. The average droplet size of 7SD-stabilized nanoemulsions was also reduced due to the enhancing on the steric repulsion. Moreover, the stability over various pH of 7SD-stabilized nanoemulsion was improved, especially at the isoelectric point (pI). Although 7SH-stabilized nanoemulsion exhibited slightly worse stability, but it accelerated the cumulative release rate in vitro digestion, which increased cumulative bioaccessibility. This study revealed that both 7SH and 7SD could be used as emulsifier to improve nanoemulsion properties for food applications.


Asunto(s)
Antígenos de Plantas/química , Curcumina/química , Emulsionantes/química , Globulinas/química , Nanocápsulas/química , Proteínas de Almacenamiento de Semillas/química , Proteínas de Soja/química , Digestión , Composición de Medicamentos , Liberación de Fármacos , Emulsiones/química , Glicosilación , Hidrólisis , Punto Isoeléctrico , Estabilidad Proteica , Propiedades de Superficie
17.
Polymers (Basel) ; 11(10)2019 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-31618966

RESUMEN

The effect of (-)-epigallocatechin-3-gallate (EGCG) on protein structure and emulsion properties of glycosylated black bean protein isolate (BBPI-G) were studied and compared to native black bean protein isolate (BBPI). The binding affinity of BBPI and BBPI-G with EGCG belonged to non-covalent interaction, which was determined by fluorescence quenching. EGCG attachment caused more disordered protein conformation, leading to a higher emulsification property. Among the different EGCG concentrations (0.10, 0.25, 0.50 mg/mL), the result revealed that the highest level of the emulsification property was obtained with 0.25 mg/mL EGCG. Therefore, the BBPI-EGCG and BBPI-G-EGCG prepared by 0.25 mg/mL EGCG were selected to fabricate oil-in-water (O/W) emulsions. After the addition of EGCG, the mean particle size of emulsions decreased with the increasing absolute value of zeta-potential, and more compact interfacial film was formed due to the higher percentage of interfacial protein adsorption (AP%). Meanwhile, EGCG also significantly reduced the lipid oxidation of emulsions.

18.
Polymers (Basel) ; 11(5)2019 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-31083356

RESUMEN

The conjugates of black bean protein isolate (BBPI) and glucose (G) were prepared via the wet heating Maillard reaction with ultrasound pretreatment. The physicochemical properties of UBBPI-G conjugates prepared by ultrasound pretreatment Maillard reaction had been compared with classical Maillard reaction (BBPI-G). The reaction rate between BBPI and glucose was speeded up by ultrasound pretreatment. A degree of glycation (DG) of 20.49 was achieved by 2 h treatment for UBBPI-G, whereas 5 h was required using the classical heating. SDS-PAGE patterns revealed that the BBPI-G conjugates with higher molecular weight were formed after glycosylation. The results of secondary structure analysis suggested that the α-helix and ß-sheet content of UBBPI-G were lower than that of BBPI-G. In addition, UBBPI-G conjugates had exhibited bathochromic shift compared with BBPI by fluorescence spectroscopy analysis. Finally, UBBPI-G achieved higher level of surface hydrophobicity, solubility, emulsification property and antioxidant activity than BBPI and BBPI-G (classical Maillard reaction).

19.
ACS Appl Mater Interfaces ; 11(17): 15528-15536, 2019 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-30950262

RESUMEN

Electrocatalytic hydrogen evolution reaction, the cornerstone of the emerging hydrogen economy, can be essentially facilitated by robustly heterostructural electrocatalysts. Herein, we report a highly active and stably heterostructural electrocatalyst consisting of NiCoP nanowires decorated with CoP nanoparticles on a nickel foam (NiCoP-CoP/NF) for effective hydrogen evolution. The CoP nanoparticles are strongly interfaced with NiCoP nanowires producing abundant electrocatalytically active sites. Combined with the integrated catalyst design, NiCoP-CoP/NF affords a remarkable hydrogen evolution performance in terms of high activity, enhanced kinetics, and outstanding durability in an alkaline electrolyte, superior to most of the Co (or Ni)-phosphide-based catalysts reported previously. Density functional theory calculations demonstrate that there is an interfacial effect between NiCoP and CoP, which allows a preferable hydrogen adsorption and thus contributes to the significantly enhanced performance. Furthermore, an electrolyzer employing NiCoP-CoP/NF as the cathode and RuO2/NF as the anode (NiCoP-CoP/NF||RuO2/NF) exhibits excellent water-splitting activity and outstanding durability, which is comparable to that of the benchmark Pt-C/NF||RuO2/NF electrolyzer.

20.
ChemSusChem ; 12(4): 858-865, 2019 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-30600929

RESUMEN

In this study, nitrogen-doped graphene nanoshells (N-GNS) were developed to support palladium nanoparticles (Pd/N-GNS) as an efficient and recyclable catalyst for the N-allylation reaction. N-GNS was synthesized through a facile hard-template method by using petroleum asphalt, followed by nitrogen doping by thermal annealing with urea, the contents and species of which could be altered by the calcination temperature. Palladium nanoparticles (Pd NPs) with an average diameter of 3.3 nm were homogeneously deposited onto the N-GNS support through a mild solvent-growth approach. The Pd/N-GNS exhibited a superior activity towards the N-allylation reaction, 6-fold higher than that of the pristine graphene nanoshells supporting the palladium catalyst. The Pd/N-GNS could be recycled several times without activity deterioration and metal leaching. The catalytic activity showed a linear correlation relationship with the pyridinic N content. Experimental and theoretical studies reveal strong metal-support interactions between the pyridinic N and palladium species, which can downsize the Pd NPs, modulate the electronic properties, and promote the adsorption of reactant, thereby significantly boosting the catalytic efficiency and stability for the N-allylation process. The present work could help unravel the roles of nitrogen-doped carbon supports and provides a feasible strategy to rationally design superior palladium catalysts for chemical transformations.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...