Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 28
Filtrar
1.
J Am Chem Soc ; 146(20): 14349-14356, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38742424

RESUMO

High-purity CO2 rather than dilute CO2 (15 vol %, CO2/N2/O2 = 15:80:5, v/v/v) similar to the flue gas is currently used as the feedstock for the electroreduction of CO2, and the liquid products are usually mixed up with the cathode electrolyte, resulting in high product separation costs. In this work, we showed that a microporous conductive Bi-based metal-organic framework (Bi-HHTP, HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene) can not only efficiently capture CO2 from the dilute CO2 under high humidity but also catalyze the electroreduction of the adsorbed CO2 into formic acid with a high current density of 80 mA cm-2 and a Faradaic efficiency of 90% at a very low cell voltage of 2.6 V. Importantly, the performance in a dilute CO2 atmosphere was close to that under a high-purity CO2 atmosphere. This is the first catalyst that can maintain exceptional eCO2RR performance in the presence of both O2 and N2. Moreover, by using dilute CO2 as the feedstock, a 1 cm-2 working electrode coating with Bi-HHTP can continuously produce a 200 mM formic acid aqueous solution with a relative purity of 100% for at least 30 h in a membrane electrode assembly (MEA) electrolyzer. The product does not contain electrolytes, and such a highly concentrated and pure formic acid aqueous solution can be directly used as an electrolyte for formic acid fuel cells. Comprehensive studies revealed that such a high performance might be ascribed to the CO2 capture ability of the micropores on Bi-HHTP and the lower Gibbs free energy of formation of the key intermediate *OCHO on the open Bi sites.

2.
J Am Chem Soc ; 146(1): 1144-1152, 2024 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-38164902

RESUMO

It is crucial to achieve continuous production of highly concentrated and pure C2 chemicals through the electrochemical CO2 reduction reaction (eCO2RR) for artificial carbon cycling, yet it has remained unattainable until now. Despite one-pot tandem catalysis (dividing the eCO2RR to C2 into two catalytical reactions of CO2 to CO and CO to C2) offering the potential for significantly enhancing reaction efficiency, its mechanism remains unclear and its performance is unsatisfactory. Herein, we selected different CO2-to-CO catalysts and CO-to-acetate catalysts to construct several tandem catalytic systems for the eCO2RR to acetic acid. Among them, a tandem catalytic system comprising a covalent organic framework (PcNi-DMTP) and a metal-organic framework (MAF-2) as CO2-to-CO and CO-to-acetate catalysts, respectively, exhibited a faradaic efficiency of 51.2% with a current density of 410 mA cm-2 and an ultrahigh acetate yield rate of 2.72 mmol m-2 s-1 under neutral conditions. After electrolysis for 200 h, 1 cm-2 working electrode can continuously produce 20 mM acetic acid aqueous solution with a relative purity of 95+%. Comprehensive studies revealed that the performance of tandem catalysts is influenced not only by the CO supply-demand relationship and electron competition between the two catalytic processes in the one-pot tandem system but also by the performance of the CO-to-C2 catalyst under diluted CO conditions.

3.
Angew Chem Int Ed Engl ; : e202410625, 2024 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-38982877

RESUMO

Electrosynthesis of urea from CO2 and NO3- is a sustainable alternative to energy-intensive industrial processes. The challenge hindering the progress is the development of advanced electrocatalysts that yield urea with both high Faradaic efficiency (FE) and current density. In this work, we designed a new two-dimensional MOF, namely PcNi-Fe-O, constructed by nickel-phthalocyanine (NiPc) ligands and square-planar FeO4 nodes. PcNi-Fe-O exhibits remarkable performance to yield urea at a high current density of 10.1 mA cm-2 with a high FE(urea) of 54.1% in a neutral aqueous solution, surpassing those of most reported electrocatalysts. No obvious performance degradation was observed over 20 hours of continuous operation at the current density of 10.1 mA cm-2. By expanding the electrode area to 25 cm2 and operating for 8 hours, we obtained 0.164 g of high-purity urea, underscoring its potential for industrial applications. Mechanism study unveiled the enhanced performance might be ascribed to the synergistic interaction between NiPc and FeO4 sites. Specifically, NH3 produced at the FeO4 site can efficiently migrate and couple with the *NHCOOH intermediate adsorbed on the urea-producing site (NiPc). This synergistic effect results in a lower energy barrier for C-N bond formation than those of the reported catalysts with single active sites.

4.
Angew Chem Int Ed Engl ; : e202412553, 2024 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-39133133

RESUMO

Efficient photocatalytic CO2 reduction coupled with the photosynthesis of pure H2O2 is a challenging and significant task. Herein, using classical CO2 photoreduction site iron porphyrinate as the linker, Ag(I) clusters were spatially separated and evenly distributed within a new metal-organic framework (MOF), namely Ag27TPyP-Fe. With water as electron donors, Ag27TPyP-Fe exhibited remarkable performances in artificial photosynthetic overall reaction with CO yield of 36.5 µmol g-1 h-1 and ca. 100% selectivity, as well as H2O2 evolution rate of 35.9 µmol g-1 h-1. Since H2O2 in the liquid phase can be more readily separated from the gaseous products of CO2 photoreduction, high-purity H2O2 with a concentration up to 0.1 mM was obtained. Confirmed by theoretical calculations and the established energy level diagram, the reductive iron(II) porphyrinates and oxidative Ag(I) clusters within an integrated framework functioned synergistically to achieve artificial photosynthesis. Furthermore, photoluminescence spectroscopy and photoelectrochemical measurements revealed that the robust connection of Ag(I) clusters and iron porphyrinate ligands facilitated efficient charge separation and rapid electron transfer, thereby enhancing the photocatalytic activity.

5.
J Am Chem Soc ; 145(49): 26783-26790, 2023 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-38014883

RESUMO

The electroreduction of CO2 into value-added liquid fuels holds great promise for addressing global environmental and energy challenges. However, achieving highly selective yielding of multi-carbon oxygenates through the electrochemical CO2 reduction reaction (eCO2RR) is a formidable task, primarily due to the sluggish asymmetric C-C coupling reaction. In this study, a novel metal-organic framework (CuSn-HAB) with unprecedented heterometallic Sn···Cu dual sites (namely, a pair of SnN2O2 and CuN4 sites bridged by µ-N atoms) was designed to overcome this limitation. CuSn-HAB demonstrated an impressive Faradic efficiency (FE) of 56(2)% for eCO2RR to alcohols, achieving a current density of 68 mA cm-2 at a low potential of -0.57 V (vs RHE). Notably, no significant degradation was observed over a continuous 35 h operation at the specified current density. Mechanistic investigations revealed that, in comparison to the copper site, the SnN2O2 site exhibits a higher affinity for oxygen atoms. This enhanced affinity plays a pivotal role in facilitating the generation of the key intermediate *OCH2. Consequently, compared to homometallic Cu···Cu dual sites (generally yielding ethylene product), the heterometallic dual sites were proved to be more thermodynamically favorable for the asymmetric C-C coupling between *CO and *OCH2, leading to the formation of the key intermediate *CO-*OCH2, which is favorable for yielding ethanol product.

6.
J Am Chem Soc ; 145(4): 2439-2447, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36657974

RESUMO

It is a very important but still challenging task to develop bifunctional electrocatalysts for highly efficient CO2 overall splitting. Herein, we report a stable metal-organic framework (denoted as PcNi-Co-O), composed of (2,3,9,10,16,17,23,24-octahydroxyphthalocyaninato)nickel(II) (PcNi-(O-)8) ligands and the planar CoO4 nodes, for CO2 overall splitting. When working as both cathode and anode catalysts (i.e., PcNi-Co-O||PcNi-Co-O), PcNi-Co-O achieved a commercial-scale current density of 123 mA cm-2 (much higher than the reported values (0.2-12 mA cm-2)) with a Faradic efficiency (CO) of 98% at a low cell voltage of 4.4 V. Mechanism studies suggested the synergistic effects between two active sites, namely, (i) electron transfer from CoO4 to PcNi sites under electric fields, resulting in the raised oxidizability/reducibility of CoO4/PcNi sites, respectively; (ii) the energy-level matching of cathode and anode catalysts can reduce the energy barrier of electron transfer between them and improve the performance of CO2 overall splitting.

7.
Sensors (Basel) ; 23(4)2023 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-36850496

RESUMO

Forest fires can destroy forest and inflict great damage to the ecosystem. Fortunately, forest fire detection with video has achieved remarkable results in enabling timely and accurate fire warnings. However, the traditional forest fire detection method relies heavily on artificially designed features; CNN-based methods require a large number of parameters. In addition, forest fire detection is easily disturbed by fog. To solve these issues, a lightweight YOLOX-L and defogging algorithm-based forest fire detection method, GXLD, is proposed. GXLD uses the dark channel prior to defog the image to obtain a fog-free image. After the lightweight improvement of YOLOX-L by GhostNet, depth separable convolution, and SENet, we obtain the YOLOX-L-Light and use it to detect the forest fire in the fog-free image. To evaluate the performance of YOLOX-L-Light and GXLD, mean average precision (mAP) was used to evaluate the detection accuracy, and network parameters were used to evaluate the lightweight effect. Experiments on our forest fire dataset show that the number of the parameters of YOLOX-L-Light decreased by 92.6%, and the mAP increased by 1.96%. The mAP of GXLD is 87.47%, which is 2.46% higher than that of YOLOX-L; and the average fps of GXLD is 26.33 when the input image size is 1280 × 720. Even in a foggy environment, the GXLD can detect a forest fire in real time with a high accuracy, target confidence, and target integrity. This research proposes a lightweight forest fire detection method (GXLD) with fog removal. Therefore, GXLD can detect a forest fire with a high accuracy in real time. The proposed GXLD has the advantages of defogging, a high target confidence, and a high target integrity, which makes it more suitable for the development of a modern forest fire video detection system.

8.
Angew Chem Int Ed Engl ; 62(22): e202301767, 2023 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-36823343

RESUMO

The development of efficient electrocatalysts with non-copper metal sites for electrochemical CO2 reduction reactions (eCO2 RR) to hydrocarbons and oxygenates is highly desirable, but still a great challenge. Herein, a stable metal-organic framework (DMA)4 [Sn2 (THO)2 ] (Sn-THO, THO6- = triphenylene-2,3,6,7,10,11-hexakis(olate), DMA = dimethylammonium) with isolated and distorted octahedral SnO6 2- active sites is reported as an electrocatalyst for eCO2 RR, showing an exceptional performance for eCO2 RR to the CH4 product rather than the common products formate and CO for reported Sn-based catalysts. The partial current density of CH4 reaches a high value of 34.5 mA cm-2 , surpassing most reported copper-based and all non-Cu metal-based catalysts. Our experimental and theoretical results revealed that the isolated SnO6 2- active site favors the formation of key *OCOH species to produce CH4 and can greatly inhibit the formation of *OCHO and *COOH species to produce *HCOOH and *CO, respectively.

9.
Angew Chem Int Ed Engl ; 62(52): e202311265, 2023 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-37782029

RESUMO

Integration of CO2 capture capability from simulated flue gas and electrochemical CO2 reduction reaction (eCO2 RR) active sites into a catalyst is a promising cost-effective strategy for carbon neutrality, but is of great difficulty. Herein, combining the mixed gas breakthrough experiments and eCO2 RR tests, we showed that an Ag12 cluster-based metal-organic framework (1-NH2 , aka Ag12 bpy-NH2 ), simultaneously possessing CO2 capture sites as "CO2 relays" and eCO2 RR active sites, can not only utilize its micropores to efficiently capture CO2 from simulated flue gas (CO2 : N2 =15 : 85, at 298 K), but also catalyze eCO2 RR of the adsorbed CO2 into CO with an ultra-high CO2 conversion of 60 %. More importantly, its eCO2 RR performance (a Faradaic efficiency (CO) of 96 % with a commercial current density of 120 mA cm-2 at a very low cell voltage of -2.3 V for 300 hours and the full-cell energy conversion efficiency of 56 %) under simulated flue gas atmosphere is close to that under 100 % CO2 atmosphere, and higher than those of all reported catalysts at higher potentials under 100 % CO2 atmosphere. This work bridges the gap between CO2 enrichment/capture and eCO2 RR.

10.
Angew Chem Int Ed Engl ; 62(42): e202308195, 2023 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-37656139

RESUMO

Solvent effect plays an important role in catalytic reaction, but there is little research and attention on it in electrochemical CO2 reduction reaction (eCO2 RR). Herein, we report a stable covalent-organic framework (denoted as PcNi-im) with imidazole groups as a new electrocatalyst for eCO2 RR to CO. Interestingly, compared with neutral conditions, PcNi-im not only showed high Faraday efficiency of CO product (≈100 %) under acidic conditions (pH ≈ 1), but also the partial current density was increased from 258 to 320 mA cm-2 . No obvious degradation was observed over 10 hours of continuous operation at the current density of 250 mA cm-2 . The mechanism study shows that the imidazole group on the framework can be protonated to form an imidazole cation in acidic media, hence reducing the surface work function and charge density of the active metal center. As a result, CO poisoning effect is weakened and the key intermediate *COOH is also stabilized, thus accelerating the catalytic reaction rate.

11.
Angew Chem Int Ed Engl ; 61(44): e202210985, 2022 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-36068177

RESUMO

Electroreduction of CO2 to CO is a promising approach for the cycling use of CO2 , while it still suffers from impractical current density and durability. Here we report a single-atom nanozyme (Ni-N5 -C) that achieves industrial-scale performance for CO2 -to-CO conversion with a Faradaic efficiency (FE) exceeded 97 % over -0.8--2.4 V vs. RHE. The current density at -2.4 V vs. RHE reached a maximum of 1.23 A cm-2 (turnover frequency of 69.7 s-1 ) with an FE of 99.6 %. No obvious degradation was observed over 100 hours of continuous operation. Compared with the planar Ni-N4 site, the square-pyramidal Ni-N5 site has an increase and a decrease in the d z 2 ${{{\rm d}}_{{z}^{2}}}$ and dxz/yz orbital energy levels, respectively, as revealed by density functional theory calculations. Thus, the Ni-N5 catalytic site is more superior to activate CO2 molecule and reduce the energy barriers as well as promote the CO desorption, thus boosting the kinetic activation process and catalytic activity.

12.
Angew Chem Int Ed Engl ; 61(36): e202206470, 2022 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-35697663

RESUMO

Electroreduction of CO2 to acetate provides a promising strategy to reduce CO2 emissions and store renewable energy, but acetate is usually a by-product. Here, we show a stable and conductive two-dimensional phthalocyanine-based covalent-organic framework (COF) as an electrocatalyst for reduction of CO2 to acetate with a single-product Faradaic efficiency (FE) of 90.3(2)% at -0.8 V (vs. RHE) and a current density of 12.5 mA cm-2 in 0.1 M KHCO3 solution. No obvious degradation was observed over 80 hours of continuous operation. Combined with the comparison of the properties of other catalysts with isolated metal active sites, theoretical calculations and in situ infrared spectroscopy revealed that the isolated copper-phthalocyanine active site with high electron density is conducive to the key step of C-C coupling of *CH3 with CO2 to produce acetate, and can avoid the coupling of *CO with *CO or *CHO to produce ethylene and ethanol.

13.
J Am Chem Soc ; 143(19): 7242-7246, 2021 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-33956435

RESUMO

Conversion from CO2 to C2H4 is important for the development of energy and the environment, but the high energy barrier of hydrogenation of the *CO intermediate and C-C coupling step tend to result in C1 compounds as the main product and thus restrict the generation of C2H4. Here, we report a metal-organic framework (denoted as PcCu-Cu-O), composed of 2,3,9,10,16,17,23,24-octahydroxyphthalo-cyaninato)copper(II) (PcCu-(OH)8) ligands and the square-planar CuO4 nodes, as the electrocatalyst for CO2 to C2H4. Compared with the discrete molecular copper-phthalocyanine (Faradaic efficiency (FE) of C2H4 = 25%), PcCu-Cu-O exhibits much higher performance for electrocatalytic reduction of CO2 to C2H4 with a FE of 50(1)% and a current density of 7.3 mA cm-2 at the potential of -1.2 V vs RHE in 0.1 M KHCO3 solution, representing the best performance reported to date. In-situ infrared spectroscopy and control experiments suggested that the enhanced electrochemical performance may be ascribed to the synergistic effect between the CuPc unit and the CuO4 unit, namely the CO on the CO-producing site (CuO4 site) can efficiently migrate and dimerize with the *CO intermediate adsorbed on the C2H4-producing site (CuPc), giving a lower C-C dimerization energy barrier.

14.
J Am Chem Soc ; 143(42): 17424-17430, 2021 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-34637290

RESUMO

Reducing CO2 into fuels via photochemical reactions relies on highly efficient photocatalytic systems. Herein, we report a new and efficient photocatalytic system for CO2 reduction. Driven by electrostatic attraction, an anionic metal-organic framework Cu-HHTP (HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene) as host and a cationic photosensitizer [Ru(phen)3]2+ (phen = 1,10-phenanthroline) as guest were self-assembled into a photocatalytic system Ru@Cu-HHTP, which showed high activity for photocatalytic CO2 reduction under laboratory light source (CO production rate of 130(5) mmol g-1 h-1, selectivity of 92.9%) or natural sunlight (CO production rate of 69.5 mmol g-1 h-1, selectivity of 91.3%), representing the remarkable photocatalytic CO2 reduction performance. More importantly, the photosensitizer [Ru(phen)3]2+ in Ru@Cu-HHTP is only about 1/500 in quantity reported in the literature. Theoretical calculations and control experiments suggested that the assembly of the catalysts and photosensitizers via electrostatic attraction interactions can provide a better charge transfer efficiency, resulting in high performance for photocatalytic CO2 reduction.

15.
Small ; 17(41): e2102102, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34510724

RESUMO

Neuroinflammation is critically involved in the repair of spinal cord injury (SCI), and macrophages associated with inflammation propel the degeneration or recovery in the pathological process. Currently, efforts have been focused on obtaining efficient therapeutic anti-inflammatory drugs to treat SCI. However, these drugs are still unable to penetrate the blood spinal cord barrier and lack the ability to target lesion areas, resulting in unsatisfactory clinical efficacy. Herein, a polymer-based nanodrug delivery system is constructed to enhance the targeting ability. Because of increased expression of matrix metalloproteinases (MMPs) in injured site after SCI, MMP-responsive molecule, activated cell-penetrating peptides (ACPP), is introduced into the biocompatible polymer PLGA-PEI-mPEG (PPP) to endow the nanoparticles with the ability for diseased tissue-targeting. Meanwhile, etanercept (ET), a clinical anti-inflammation treatment medicine, is loaded on the polymer to regulate the polarization of macrophages, and promote locomotor recovery. The results show that PPP-ACPP nanoparticles possess satisfactory lesion targeting effects. Through inhibited consequential production of proinflammation cytokines and promoted anti-inflammation cytokines, ET@PPP-ACPP could decrease the percentage of M1 macrophages and increase M2 macrophages. As expected, ET@PPP-ACPP accumulates in lesion area and achieves effective treatment of SCI; this confirmed the potential of nano-drug loading systems in SCI immunotherapy.


Assuntos
Traumatismos da Medula Espinal , Anti-Inflamatórios/uso terapêutico , Humanos , Imunoterapia , Macrófagos , Metaloproteinases da Matriz/uso terapêutico , Traumatismos da Medula Espinal/tratamento farmacológico
16.
Chem Commun (Camb) ; 60(27): 3669-3672, 2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38456336

RESUMO

It is important and challenging to utilise CO2 and NO3- as a feedstock for electrosynthesis of urea. Herein, we reported a stable 2D metal-organic framework (MOF) Cu-HATNA, possessing planar CuO4 active sites, as an efficient electrocatalyst for coupling CO2 and NO3- into urea, achieving a high yield rate of 1.46 g h-1 gcat-1 with a current density of 44.2 mA cm-1 at -0.6 V vs. RHE. This performance surpasses most of the previously reported catalysts, revealing the great prospects of MOFs in sustainable urea synthesis.

17.
Food Funct ; 15(11): 6134-6146, 2024 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-38767386

RESUMO

Deoxynivalenol (DON) is a prevalent mycotoxin that primarily contaminates cereal crops and animal feed, posing a significant risk to human and animal health. In recent years, an increasing number of Devosia strains have been identified as DON degradation bacteria, and significant efforts have been made to explore their potential applications in the food and animal feed industries. However, the characteristics and mechanisms of DON degradation in Devosia strains are still unclear. In this study, we identified a novel DON degrading bacterium, Devosia sp. D-G15 (D-G15), from soil samples. The major degradation products of DON in D-G15 were 3-keto-DON, 3-epi-DON and an unidentified product, compound C. The cell viability assay showed that the DON degradation product of D-G15 revealed significantly reduced toxicity to HEK293T cells compared to DON. Three enzymes for DON degradation were further identified, with G15-DDH converting DON to 3-keto-DON and G15-AKR1/G15-AKR6 reducing 3-keto-DON to 3-epi-DON. Interestingly, genome comparison of Devosia strains showed that the pyrroloquinoline quinone (PQQ) synthesis gene cluster is a unique feature of DON degradation strains. Subsequently, adding PQQ to the cultural media of Devosia strains without PQQ synthesis genes endowed them with DON degradation activity. Furthermore, a novel DON-degrading enzyme G13-DDH (<30% homology with known DON dehydrogenase) was identified from a Devosia strain that lacks PQQ synthesis ability. In summary, a novel DON degrading Devosia strain and its key enzymes were identified, and PQQ production was found as a distinct feature among Devosia strains with DON degradation activity, which is important for developing Devosia strain-based technology in DON detoxification.


Assuntos
Cofator PQQ , Tricotecenos , Tricotecenos/metabolismo , Cofator PQQ/metabolismo , Humanos , Células HEK293 , Hyphomicrobiaceae/metabolismo , Hyphomicrobiaceae/genética , Microbiologia do Solo
18.
Adv Mater ; 35(36): e2212178, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37204161

RESUMO

Facilely synthesized nanoradiosensitizers with well-controlled structure and multifunctionality are greatly desired to address the challenges of cancer radiotherapy. In this work, a universal method is developed for synthesizing chalcogen-based TeSe nano-heterojunctions (NHJs) with rod-, spindle-, or dumbbell-like morphologies by engineering the surfactant and added selenite. Interestingly, dumbbell-shaped TeSe NHJs (TeSe NDs) as chaperone exhibit better radio-sensitizing activities than the other two nanostructural shapes. Meanwhile, TeSe NDs can serve as cytotoxic chemodrugs that degrade to highly toxic metabolites in acidic environment and deplete GSH within tumor to facilitate radiotherapy. More importantly, the combination of TeSe NDs with radiotherapy significantly decreases regulatory T cells and M2-phenotype tumor-associated macrophage infiltrations within tumors to reshape the immunosuppressive microenvironment and induce robust T lymphocytes-mediated antitumor immunity, resulting in great abscopal effects on combating distant tumor progression. This study provides a universal method for preparing NHJ with well-controlled structure and developing nanoradiosensitizers to overcome the clinical challenges of cancer radiotherapy.


Assuntos
Antineoplásicos , Neoplasias , Humanos , Imunoterapia , Antineoplásicos/farmacologia , Neoplasias/tratamento farmacológico , Linfócitos T Reguladores , Microambiente Tumoral
19.
Chem Asian J ; 18(15): e202300281, 2023 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-37147935

RESUMO

Herein, a stable metal-azolate framework with cyclic trinickel(II) clusters, namely [Ni3 (µ3 -O)(BTPP)(OH)(H2 O)2 ] (Ni-BTPP, H3 BTPP=1,3,5-tris((1H-pyrazol-4-yl)phenylene)benzene), achieved a current density of 50 mA cm-2 at a cell voltage of 1.8 V in 1.0 M KOH solution, while the current density of 20%Pt/C@NF||IrO2 @NF is just 35.8 mA cm-2 at 2.0 V under the same condition. Moreover, no obvious degradation was observed over 12 hours of continuous operation at a large current density of 50 mA cm-2 . Theoretical calculations revealed that the µ3 -O atom in the cyclic trinickel(II) cluster serves as hydrogen-bonding acceptor to facilitate the dissociation of a H2 O molecule adsorbed on the adjacent Ni(II) ion, giving a lower energy barrier of H2 O dissociation compared with Pt/C; meanwhile, the µ3 -O atom can also participate in the water oxidation reaction to couple with the adjacent *OH adsorbed on Ni(II) ion, providing a low-energy coupling pathway, thus Ni-BTPP achieves a high performance for overall water splitting.

20.
Food Chem ; 423: 136274, 2023 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-37159968

RESUMO

Deoxynivalenol (DON) is the most frequently contaminated mycotoxin in food and feed worldwide, causing significant economic losses and health risks. Physical and chemical detoxification methods are widely used, but they cannot efficiently and specifically remove DON. In the study, the combination of bioinformatics screening and experimental verification confirmed that sorbose dehydrogenase (SDH) can effectively convert DON to 3-keto-DON and a substance that removes four hydrogen atoms for DON. Through rational design, the Vmax of the mutants F103L and F103A were increased by 5 and 23 times, respectively. Furthermore, we identified catalytic sites W218 and D281. SDH and its mutants have broad application conditions, including temperature ranges of 10-45 °C and pH levels of 4-9. Additionally, the half-lives of F103A at 90 °C (processing temperature) and 30 °C (storage temperature) were 60.1 min and 100.5 d, respectively. These results suggest that F103A has significant potential in the detoxification application of DON.


Assuntos
Desidrogenases de Carboidrato , Micotoxinas , Temperatura , Contaminação de Alimentos/análise
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA