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1.
ACS Appl Mater Interfaces ; 16(13): 16253-16260, 2024 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-38514257

RESUMEN

The CuGaTe2 thermoelectric material has garnered widespread attention as an inexpensive and nontoxic material for mid-temperature thermoelectric applications. However, its development has been hindered by its low intrinsic carrier concentration and high thermal conductivity. This study investigates the band structure and thermoelectric properties of (CuGaTe2)1-x (ZnSe)x (x = 0, 0.25%, 0.5%, 1%, 1.5%, and 2%). The research revealed that the incorporation of Zn and Se atoms enhanced the level of band degeneracy and electron density of states near Fermi level, significantly raising carrier concentration through the formation of ZnGa- point defects. Simultaneously, when the doping content reached 1.5%, the ZnTe second phase emerged, collaborating with point defects and high-density dislocations, effectively scattering phonons and substantially reducing lattice thermal conductivity. Therefore, introducing ZnSe can simultaneously optimize the material's electrical and thermal transport properties. The (CuGaTe2)0.985(ZnSe)0.015 sample reaches peak ZT of 1.32 at 823 K, representing a 159% increase compared to pure CuGaTe2.

2.
ACS Nano ; 18(5): 4308-4319, 2024 Feb 06.
Artículo en Inglés | MEDLINE | ID: mdl-38261610

RESUMEN

The intrinsic roadblocks for designing promising Pt-based oxygen reduction reaction (ORR) catalysts emanate from the strong scaling relationship and activity-stability-cost trade-offs. Here, a carbon-supported Pt nanoparticle and a Mn single atom (PtNP-MnSA/C) as in situ constructed PtNP-MnSA pairs are demonstrated to be an efficient catalyst to circumvent the above seesaws with only ∼4 wt % Pt loadings. Experimental and theoretical investigations suggest that MnSA functions not only as the "assist" for Pt sites to cooperatively facilitate the dissociation of O2 due to the strong electronic polarization, affording the dissociative pathway with reduced H2O2 production, but also as an electronic structure "modulator" to downshift the d-band center of Pt sites, alleviating the overbinding of oxygen-containing intermediates. More importantly, MnSA also serves as a "stabilizer" to endow PtNP-MnSA/C with excellent structural stability and low Fenton-like reactivity, resisting the fast demetalation of metal sites. As a result, PtNPs-MnSA/C shows promising ORR performance with a half-wave potential of 0.93 V vs reversible hydrogen electrode and a high mass activity of 1.77 A/mgPt at 0.9 V in acid media, which is 19 times higher than that of commercial Pt/C and only declines by 5% after 80,000 potential cycles. Specifically, PtNPs-MnSA/C reaches a power density of 1214 mW/cm2 at 2.87 A/cm2 in an H2-O2 fuel cell.

3.
ACS Nano ; 18(2): 1678-1689, 2024 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-38164927

RESUMEN

Incorporating donor doping into Mg3Sb1.5Bi0.5 to achieve n-type conductivity is one of the crucial strategies for performance enhancement. In pursuit of higher thermoelectric performance, we herein report co-doping with Te and Y to optimize the thermoelectric properties of Mg3Sb1.5Bi0.5, achieving a peak ZT exceeding 1.7 at 703 K in Y0.01Mg3.19Sb1.5Bi0.47Te0.03. Guided by first-principles calculations for compositional design, we find that Te-doping shifts the Fermi level into the conduction band, resulting in n-type semiconductor behavior, while Y-doping further shifts the Fermi level into the conduction band and reduces the bandgap, leading to enhanced thermoelectric performance with a power factor as high as >20 µW cm-1 K-2. Additionally, through detailed micro/nanostructure characterizations, we discover that Te and Y co-doping induces dense crystal and lattice defects, including local lattice distortions and strains caused by point defects, and densely distributed grain boundaries between nanocrystalline domains. These defects efficiently scatter phonons of various wavelengths, resulting in a low thermal conductivity of 0.83 W m-1 K-1 and ultimately achieving a high ZT. Furthermore, the dense lattice defects induced by co-doping can further strengthen the mechanical performance, which is crucial for its service in devices. This work provides guidance for the composition and structure design of thermoelectric materials.

4.
J Colloid Interface Sci ; 658: 528-539, 2024 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-38128196

RESUMEN

The development of low-cost and high-efficiency electrocatalysts for the oxygen evolution reaction (OER) is essential to produce high-purity hydrogen in large scale. Herein, a three-dimensional (3D) seaweed-like hierarchical structure was fabricated using two-dimensional (2D) NiMn LDH nanosheets wrapped on one-dimensional (1D) NiSe nanowires with nickel foam (NF) as a substrate (NiSe@NiMn LDH/NF) via hydrothermal and electrodeposition processes. Owing to the strong interfacial synergy, 3D seaweed-like hierarchical structure, higher conductivity, and strong structural stability, the NiSe@NiMn LDH/NF exhibited superior OER performance with an overpotential of 287 mV at 100 mA cm-2, and stably operated for 160 h at large current. Moreover, the overall water splitting system with NiSe@NiMn LDH/NF as the anode and Pt/C/NF as the cathode exhibited a low cell voltage of 1.59/1.64 V to reach 50/100 mA cm-2, and excellent stability for 110 h at 300 mA cm-2. The density function theory (DFT) calculations unveiled that NiSe@NiMn LDH enabled the interfacial synergy, reallocating the electron density at the interface, and further weakening the energy barrier of OH* by strengthening chemical bonds with OH* intermediates to improve the intrinsic OER activity.

5.
Plant Cell ; 36(5): 1844-1867, 2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38146915

RESUMEN

Hypothetical chloroplast open reading frames (ycfs) are putative genes in the plastid genomes of photosynthetic eukaryotes. Many ycfs are also conserved in the genomes of cyanobacteria, the presumptive ancestors of present-day chloroplasts. The functions of many ycfs are still unknown. Here, we generated knock-out mutants for ycf51 (sll1702) in the cyanobacterium Synechocystis sp. PCC 6803. The mutants showed reduced photoautotrophic growth due to impaired electron transport between photosystem II (PSII) and PSI. This phenotype results from greatly reduced PSI content in the ycf51 mutant. The ycf51 disruption had little effect on the transcription of genes encoding photosynthetic complex components and the stabilization of the PSI complex. In vitro and in vivo analyses demonstrated that Ycf51 cooperates with PSI assembly factor Ycf3 to mediate PSI assembly. Furthermore, Ycf51 interacts with the PSI subunit PsaC. Together with its specific localization in the thylakoid membrane and the stromal exposure of its hydrophilic region, our data suggest that Ycf51 is involved in PSI complex assembly. Ycf51 is conserved in all sequenced cyanobacteria, including the earliest branching cyanobacteria of the Gloeobacter genus, and is also present in the plastid genomes of glaucophytes. However, Ycf51 has been lost from other photosynthetic eukaryotic lineages. Thus, Ycf51 is a PSI assembly factor that has been functionally replaced during the evolution of oxygenic photosynthetic eukaryotes.


Asunto(s)
Proteínas Bacterianas , Sistemas de Lectura Abierta , Complejo de Proteína del Fotosistema I , Synechocystis , Complejo de Proteína del Fotosistema I/metabolismo , Complejo de Proteína del Fotosistema I/genética , Synechocystis/genética , Synechocystis/metabolismo , Sistemas de Lectura Abierta/genética , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/genética , Cloroplastos/metabolismo , Fotosíntesis/genética , Tilacoides/metabolismo , Complejo de Proteína del Fotosistema II/metabolismo , Complejo de Proteína del Fotosistema II/genética , Mutación
6.
ACS Appl Mater Interfaces ; 15(46): 53594-53603, 2023 Nov 22.
Artículo en Inglés | MEDLINE | ID: mdl-37948678

RESUMEN

Mg3Sb2-based thermoelectric materials can convert heat and electricity into each other, making them a promising class of environmentally friendly materials. Further improving the electrical performance while effectively reducing the thermal conductivity is a crucial issue. In this paper, under the guidance of the oneness principle calculation, we designed a thermoelectric Zintl phase based on Mg3.2Sb1.5Bi0.5 doped with Tb and Er. Calculation results show that using Tb and Er as cationic site dopants effectively improves the electrical properties and reduces the lattice thermal conductivity. Experimental results confirmed the effectiveness of codoping and effectively enhanced thermoelectric performance. The most immense ZT value obtained by the Mg3.185Tb0.01Er0.005Sb1.5Bi0.5 sample was 1.71. In addition, the average Young's modulus of the Mg3.185Tb0.01Er0.005Sb1.5Bi0.5 sample is 51.85 GPa, and the Vickers hardness is 0.99 GPa. Under the same test environment, the material was subjected to 12 cycles in the temperature range of 323-723 K, and the average power factor error range was 1.8% to 2.1%, which is of practical significance for its application in actual device scenarios.

7.
Nat Commun ; 14(1): 6064, 2023 09 28.
Artículo en Inglés | MEDLINE | ID: mdl-37770453

RESUMEN

Neurotoxicity of organophosphate compounds (OPs) can catastrophically cause nervous system injury by inhibiting acetylcholinesterase (AChE) expression. Although artificial systems have been developed for indirect neuroprotection, they are limited to dissociating P-O bonds for eliminating OPs. However, these systems have failed to overcome the deactivation of AChE. Herein, we report our finding that Al3+ is engineered onto the nodes of metal-organic framework to synthesize MOF-808-Al with enhanced Lewis acidity. The resultant MOF-808-Al efficiently mimics the catalytic behavior of AChE and has a self-defense ability to break the activity inhibition by OPs. Mechanism investigations elucidate that Al3+ Lewis acid sites with a strong polarization effect unite the highly electronegative -OH groups to form the enzyme-like catalytic center, resulting in superior substrate activation and nucleophilic attack ability with a 2.7-fold activity improvement. The multifunctional MOF-808-Al, which has satisfactory biosafety, is efficient in reducing neurotoxic effects and preventing neuronal tissue damage.


Asunto(s)
Acetilcolinesterasa , Biomimética , Acetilcolinesterasa/química , Neuroprotección , Organofosfatos
8.
Nanoscale Horiz ; 8(6): 812-826, 2023 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-37016980

RESUMEN

Exploring eco-friendly and cost-effective strategies for structure engineering at the nanoscale is important for boosting heterogeneous catalysis but still under a long-standing challenge. Herein, multifunctional polyphenol tannic acid, a low-cost natural biomass containing catechol and galloyl species, was employed as a green reducing agent, chelating agent, and stabilizer to prepare Au nanoparticles, which were dispersed on different-shaped CeO2 supports (e.g., rod, flower, cube, and octahedral). Systematic characterizations revealed that Au/CeO2-rod had the highest oxygen vacancy density and Ce(III) proportion, favoring the dispersion and stabilization of the metal active sites. Using isopropanol as a hydrogen-transfer reagent, deep insights into the structure-activity relationship of the Au/CeO2 catalysts with various morphologies of CeO2 in the catalytic nitrobenzene transfer hydrogenation reaction were gained. Notably, the catalytic performance followed the order: Au/CeO2-rod (110), (100), (111) > Au/CeO2-flower (100), (111) > Au/CeO2-cube (100) > Au/CeO2-octa (111). Au/CeO2-rod displayed the highest conversion of 100% nitrobenzene and excellent stability under optimal conditions. Moreover, DFT calculations indicated that nitrobenzene molecules had a suitable adsorption energy and better isopropanol dehydrogenation capacity on the Au/CeO2 (110) surface. A reaction pathway and the synergistic catalytic mechanism for catalytic nitrobenzene transfer hydrogenation are proposed based on the results. This work demonstrates that CeO2 structure engineering is an efficient strategy for fabricating advanced and environmentally benign materials for nitrobenzene hydrogenation.

9.
Artículo en Inglés | MEDLINE | ID: mdl-36898088

RESUMEN

Direct dehydrogenation of propane (PDH) has already been implemented worldwide in industrial processes to produce value-added propylene. The discovery of earth-abundant and environmentally friendly metal with high activity in C-H cleavage is of great importance. Co species encapsulated within zeolite are highly efficient for catalyzing direct dehydrogenation. However, exploring a promising Co catalyst remains a nontrivial target. Direct control of the regioselective distribution of Co species in the zeolite framework through altering their crystal morphology gives opportunities to modify the metallic Lewis acidic features, thus providing an active and appealing catalyst. Herein, we achieved the regioselective localization of highly active subnanometric CoO clusters in straight channels of siliceous MFI zeolite nanosheets with controllable thickness and aspect ratio. The subnanometric CoO species were identified by different types of spectroscopies, probe measurements, and density functional theory calculations, as the coordination site for the electron-donating propane molecules. The catalyst showed promising catalytic activity for the industrially important PDH with propane conversion of 41.8% and propylene selectivity higher than 95% and was durable during 10 successive regeneration cycles. These findings highlight a green and facile method to synthesize metal-containing zeolitic materials with regioselective metal distribution and also to open up a future perspectives for designing advanced catalysts with integrated advantages of the zeolitic matrix and metal structures.

10.
Nanomaterials (Basel) ; 13(4)2023 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-36839096

RESUMEN

Herein, the hierarchical porous catalyst of 3-dimensional ordered macro-mesoporous (3DOMM) Al2O3 supported active PtSn nanoparticles (NPs) was prepared by the combined synthesized path of evaporation-induced self-assembly with colloid crystal template (EISA-CCT) methods. The hierarchical macro-mesoporous composite structure can markedly increase the specific surface area, accommodate the diffusion of propene, and decrease the number of surface acid sites. In addition, the special surface property and pore structure of 3DOMM-Al2O3 can modify the interaction between metals and substrates, as well as stabilize the metal nanoparticle, which promotes the formation of a highly active and stable PtSn phase. The PtSn/3DOMM-Al2O3 catalyst exhibits higher productivity and stability than PtSn/Al2O3 catalysts with macropore and mesopore structures. The PtSn/3DOMM-Al2O3 catalyst displays the best catalytic performance with propylene selectivity over 95% at a propane conversion of 33.9%. The study of the ordered hierarchical porous structure of PtSn/3DOMM-Al2O3 catalysts can contribute to obtaining improved catalysts in industrial processes.

11.
Proc Natl Acad Sci U S A ; 120(10): e2206619120, 2023 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-36848552

RESUMEN

Selective oxidation of methane to organic oxygenates over metal-organic frameworks (MOFs) catalysts at low temperature is a challenging topic in the field of C1 chemistry because of the inferior stability of MOFs. Modifying the surface of Cu-BTC via hydrophobic polydimethylsiloxane (PDMS) at 235 °C under vacuum not only can dramatically improve its catalytic cycle stability in a liquid phase but also generate coordinatively unsaturated Cu(I) sites, which significantly enhances the catalytic activity of Cu-BTC catalyst. The results of spectroscopy characterizations and theoretical calculation proved that the coordinatively unsaturated Cu(I) sites made H2O2 dissociative into •OH, which formed Cu(II)-O active species by combining with coordinatively unsaturated Cu(I) sites for activating the C-H bond of methane. The high productivity of C1 oxygenates (CH3OH and CH3OOH) of 10.67 mmol gcat.-1h-1 with super high selectivity of 99.6% to C1 oxygenates was achieved over Cu-BTC-P-235 catalyst, and the catalyst possessed excellent reusability.

12.
ACS Appl Mater Interfaces ; 15(6): 8208-8216, 2023 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-36734007

RESUMEN

Spinel-type manganese oxide is considered as a typical cobalt-free high-voltage cathode material for lithium-ion battery applications because of its low cost, non-toxicity, and easy preparation. Nevertheless, severe capacity fading during charge and discharge limits its commercialization. Therefore, understanding the electrochemical properties and its modification mechanism of spinel-type manganese oxide for a lithium-ion battery is of great research interest. Herein, we presented a theoretical study regarding the discharge process of LiMn2O4 and LiNi0.5Mn1.5O4 using first-principles calculations based on density functional theory. We found that the discharge process is accompanied by an increase in unit cell volume and lattice distortion. Moreover, 25% Ni-substitution increases the average calculated voltage of LiMn2O4 from 3.83 to 4.61 V, which is very close to the experimental value. The electronic structure is further discussed to understand the mechanism of voltage increase. In addition, the Ni element also reduces the Li-ion diffusion barrier by 0.06 eV, which helps to improve the intrinsic rate performance of LiMn2O4. Our research can provide insight into how Ni-substitution influences the voltage and diffusion barrier of LiMn2O4 and pave the way for other spinel-type manganese oxide electrode applications.

13.
ACS Appl Mater Interfaces ; 15(8): 10696-10708, 2023 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-36791310

RESUMEN

The rational design and in-depth understanding of the structure-activity relationship (SAR) of hydrogen and oxygen evolution reaction (HER and OER) bifunctional electrocatalysts are vital to decreasing the energy consumption of hydrogen production by electrochemical water splitting. Herein, we report an inducing electron delocalization method where Fe single atoms as inducers are used to regulate the electron structure of Au nanoclusters by the M-Nx-C substrate to acquire satisfactory intrinsic HER activity. Meanwhile, Fe single atoms also serve as efficient OER active sites to construct bifunctional electrocatalysts. On account of the strong synergistic effect between Au nanoclusters and Fe single atoms, the hybrid catalyst Au-Fe1NC/NF performs an outstanding alkaline HER and OER activity. Only 35.6 mV, 246 mV, and 1.52 V are needed to reach 10 mA cm-2 for alkaline HER, OER, and two-electrode electrolytic cells, respectively. In addition, the bifunctional electrocatalysts also display excellent electrochemical stability. DFT calculations demonstrate that the strong synergistic effect can enhance the O-H bond activation ability of Au nanoclusters and upshift the d-band center of the Fe single atom to promote alkaline electrocatalytic water splitting. The strong synergistic effect is proven to arise from the electron delocalization of Au nanoclusters triggered by Fe single atoms.

14.
Nano Lett ; 23(1): 267-275, 2023 01 11.
Artículo en Inglés | MEDLINE | ID: mdl-36580489

RESUMEN

Great efforts have been made to expand the application fields of nanozymes, which puts forward requirements for nanozymes with both superior catalytic activity and specificity. Herein, we reported the high-indexed intermetallic Pt3Sn (H-Pt3Sn) with high peroxidase-like activity and specificity. The resultant H-Pt3Sn exhibits a specific activity of 345.3 U/mg, which is 1.82 times higher than Pt. Moreover, H-Pt3Sn possesses negligible oxidase-like and catalase-like activities, achieving superior catalytic specificity toward H2O2 activation. Experimental and theoretical calculations reveal both the splitting energy for adsorbed H2O2 and the energy barrier for the rate-determining step of H-Pt3Sn are significantly decreased compared with Pt3Sn and Pt. Finally, a nanozyme-linked immunosorbent assay is successfully developed, achieving the sensitive and accurate colorimetric detection for carcinoembryonic antigen with a low detection limit of 0.49 pg/mL and showing practical feasibility in serum sample detection.


Asunto(s)
Peróxido de Hidrógeno , Peroxidasa , Peroxidasas , Inmunoensayo , Colorimetría
15.
Food Res Int ; 162(Pt B): 112151, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-36461412

RESUMEN

Cannabis sativa L., has gained increasing attention due to its potential applications in various fields. However, the compositions of hemp seeds from different producing regions are quite different, significantly affects resource utilization. This work conducted the regional differentiation of hemp seeds from Dongbei, Guangxi, Inner Mongolia and Shanxi in China based on the headspace solid phase micro-extraction coupled with gas chromatography-mass spectrometry (HS-SPME/GC-MS) and multivariate analysis. Moreover, the chemical composition, amino acid and fatty acid profiles of hemp seeds and antioxidant activities of hemp protein isolate were evaluated from above four producing regions. The results showed that hemp seeds had large amounts of fat (24.30-34.65%) and protein (21.87-23.40%) with ideal amino acid and fatty acid profiles and large amounts of volatiles. More than 300 volatile compounds were detected, and 35 key contributors to the unique aroma were finally identified out of 110 volatile compounds with odor activity values (OAVs), including 14 aldehydes, 2 ketones, 4 alcohols, 2 esters, 1 acid, 3 aromatics, 5 terpenes and 4 other compounds. The content of alcohols in all hemp seeds was highest and 16 unique volatiles only found in hemp seeds from Shanxi. Meanwhile, the VIP scores indicated that acetic acid, hexanal, hexan-1-ol and eucalyptol contributed the most to the difference among groups. According to the results of fuzzy comprehensive evaluation, the hemp seeds from Shanxi seemed to have the better quality. Therefore, multivariate analysis combined with HS-SPME/GC-MS could effectively distinguish hemp seeds from different producing regions, and thus decipher the geographical characteristics of raw materials.


Asunto(s)
Cannabis , Microextracción en Fase Sólida , Cromatografía de Gases y Espectrometría de Masas , China , Semillas , Aminoácidos , Ácidos Grasos
16.
Chem Sci ; 13(45): 13574-13581, 2022 Nov 23.
Artículo en Inglés | MEDLINE | ID: mdl-36507158

RESUMEN

The large-scale application of nanozymes remains a significant challenge owing to their unsatisfactory catalytic performances. Featuring a unique electronic structure and coordination environment, single-atom nanozymes provide great opportunities to vividly mimic the specific metal catalytic center of natural enzymes and achieve superior enzyme-like activity. In this study, the spin state engineering of Fe single-atom nanozymes (FeNC) is employed to enhance their peroxidase-like activity. Pd nanoclusters (PdNC) are introduced into FeNC, whose electron-withdrawing properties rearrange the spin electron occupation in Fe(ii) of FeNC-PdNC from low spin to medium spin, facilitating the heterolysis of H2O2 and timely desorption of H2O. The spin-rearranged FeNC-PdNC exhibits greater H2O2 activation activity and rapid reaction kinetics compared to those of FeNC. As a proof of concept, FeNC-PdNC is used in the immunosorbent assay for the colorimetric detection of prostate-specific antigen and achieves an ultralow detection limit of 0.38 pg mL-1. Our spin-state engineering strategy provides a fundamental understanding of the catalytic mechanism of nanozymes and facilitates the design of advanced enzyme mimics.

17.
ACS Nano ; 16(12): 21266-21274, 2022 Dec 27.
Artículo en Inglés | MEDLINE | ID: mdl-36441949

RESUMEN

The development of advanced electrocatalysts with satisfactory C1 pathway selectivity for the ethanol oxidation reaction (EOR) is critical. Herein, a bubbling CO-induced gelation method is developed in acetic acid at 50 °C to construct single-atom W-doped Pd metallene aerogels (denoted as SA W-Pd MAs) within 1 h. In light of the metallene structural advantages of noble metal aerogels and single-atom W decoration, the resultant SA W-Pd MAs exhibit an outstanding EOR performance with high C1 pathway selectivity. Density functional theory calculations validate that the SA W-Pd MAs greatly improve the formation of the CH3O intermediate and the transformation of poisonous CO species to CO2, thus resulting in high C1 pathway selectivity. Therefore, this work not only offers an effective gelation method to fabricate noble metal aerogels with atomic-scale building blocks but also presents guidance to develop high-efficiency EOR electrocatalysts.

18.
ChemSusChem ; 15(20): e202201205, 2022 Oct 21.
Artículo en Inglés | MEDLINE | ID: mdl-36043340

RESUMEN

It is of great significance to design highly efficient electrocatalysts with abundant earth elements instead of precious metals for water splitting. Herein, Mo-doped NiFe-layered double hydroxides/NiSe heterostructure (Mo-NiFe LDH/NiSe) was fabricated by coupling Mo-doped NiFe LDH and NiSe on nickel foam (NF). The heterostructure electrocatalyst showed ultra-low overpotential (250 mV) and remarkable durability for oxygen evolution reaction (OER) at 150 mA cm-2 . Both theoretical and experimental results confirmed that Mo doping and interfacial synergism induced the interfacial charge redistribution and the lifted d-band center to weaken the energy barrier (EB) of the formation of OOH* . Mo doping also facilitated the surface reconstruction of NiFe LDH into Ni(Fe)OOH as the active sites under electro-oxidation process. This work provides a facile strategy for electronic modulation and surface reconstruction of OER electrocatalyst by transition metal doping and heterostructure generation.

19.
Angew Chem Int Ed Engl ; 61(36): e202207807, 2022 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-35789179

RESUMEN

The electrocatalytic nitrogen reduction reaction (NRR) on metal-free catalysts is an attractive alternative to the industrial Haber-Bosch process. However, the state-of-the-art metal-free electrocatalysts still suffer from low Faraday efficiencies and low ammonia yields. Herein, we present a molecular design strategy to develop a defective boron carbon nitride (BCN) catalyst with the abundant unsaturated B and N atoms as Lewis acid and base sites, which upgrades the catalyst from a single "Lewis acid catalysis" to "frustrated Lewis pairs (FLPs) catalysis." 14 N2 /15 N2 exchange experiments and density functional theory (DFT) calculations reveal that FLPs can adsorb an N2 molecule to form a six-membered ring intermediate, which enables the cleavage of N2 via a pull-pull effect, thereby significantly reducing the energy barrier to -0.28 eV. Impressively, BCN achieves a high Faraday efficiency of 18.9 %, an ammonia yield of 20.9 µg h-1 mg-1 cat. , and long-term durability.

20.
Pol J Microbiol ; 71(2): 279-292, 2022 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-35716166

RESUMEN

Oenococcus oeni is an important microorganism in wine-making-related engineering, and it improves wine quality and stability through malolactic fermentation. Although the genomes of more than 200 O. oeni strains have been sequenced, only a few include completed genome maps. Here, the genome sequence of O. oeni SD-2a, isolated from Shandong, China, has been determined. It is a fully assembled genome sequence of this strain. The complete genome is 1,989,703 bp with a G+C content of 37.8% without a plasmid. The genome includes almost all the essential genes involved in central metabolic pathways and the stress genes reported in other O. oeni strains. Some natural competence-related genes, like comEA, comEC, comFA, comG operon, and comFC, suggest that O. oeni SD-2a may have natural transformation potential. A comparative genomics analysis revealed 730 gene clusters in O. oeni SD-2a homologous to those in four other lactic acid bacteria species (O. oeni PSU-1, O. oeni CRBO-11381, Lactiplantibacillus plantarum UNQLp11, and Pediococcus pentosaceus KCCM40703). A collinearity analysis showed poor collinearity between O. oeni SD-2a and O. oeni PSU-1, indicating great differences in their evolutionary histories. The results provide general knowledge of O. oeni SD-2a and lay the foundation for specific gene function analyses.


Asunto(s)
Oenococcus , Vino , Fermentación , Genómica , Oenococcus/genética , Vino/análisis , Vino/microbiología
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