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1.
Plant J ; 115(1): 97-107, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36995355

RESUMO

Identification of unknown metabolites and their biosynthetic genes is an active research area in plant specialized metabolism. By following a gene-metabolite association from a genome-wide association study of Arabidopsis stem metabolites, we report a previously unknown metabolite, 2-hydroxy-2-(1-hydroxyethyl)pentanoic acid glucoside, and demonstrated that UGT76F1 is responsible for its production in Arabidopsis. The chemical structure of the glucoside was determined by a series of analyses, including tandem MS, acid and base hydrolysis, and NMR spectrometry. T-DNA knockout mutants of UGT76F1 are devoid of the glucoside but accumulate increased levels of the aglycone. 2-hydroxy-2-(1-hydroxyethyl)pentanoic acid is structurally related to the C7-necic acid component of lycopsamine-type pyrrolizidine alkaloids such as trachelantic acid and viridifloric acid. Feeding norvaline greatly enhances the accumulation of 2-hydroxy-2-(1-hydroxyethyl)pentanoic acid glucoside in wild-type but not the UGT76F1 knockout mutant plants, providing evidence for an orthologous C7-necic acid biosynthetic pathway in Arabidopsis despite the apparent lack of pyrrolizidine alkaloids.


Assuntos
Arabidopsis , Alcaloides de Pirrolizidina , Arabidopsis/genética , Arabidopsis/metabolismo , Estudo de Associação Genômica Ampla , Alcaloides de Pirrolizidina/química , Alcaloides de Pirrolizidina/metabolismo , Plantas/metabolismo , Glucosídeos
2.
J Am Chem Soc ; 146(33): 23146-23157, 2024 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-39109994

RESUMO

The poor durability of Ru-based catalysts limits the practical application in proton exchange membrane water electrolysis (PEMWE). Here, we report that the asymmetric active units in Ru1-xMxO2 (M = Sb, In, and Sn) binary solid solution oxides are constructed by introducing acid-resistant p-block metal sites, breaking the activity and stability limitations of RuO2 in acidic oxygen evolution reaction (OER). Constructing highly asymmetric Ru-O-Sb units with a strong electron delocalization effect significantly shortens the spatial distance between Ru and Sb sites, improving the bonding strength of the overall structure. The unique two-electron redox couples at Sb sites in asymmetric active units trigger additional chemical steps at different OER stages, facilitating continuous proton transfer. The optimized Ru0.8Sb0.2O2 solid solution requires a superlow overpotential of 160 mV at 10 mA cm-2 and a record-breaking stability of 1100 h in an acidic electrolyte. Notably, the scale-prepared Ru0.8Sb0.2O2 achieves efficient PEMWE performance under industrial conditions. General mechanism analysis shows that the enhanced proton transport in the asymmetric Ru-O-M unit provides a new working pathway for acidic OER, breaking the scaling relationship without sacrificing stability.

3.
J Am Chem Soc ; 2024 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-38847362

RESUMO

Prussian blue analogue (PBA)/metal-organic frameworks (MOFs) are multifunctional precursors for the synthesis of metal/metal compounds, carbon, and their derived composites (P/MDCs) in chemical, medical, energy, and other applications. P/MDCs combine the advantages of both the high specific surface area of PBA/MOF and the electronic conductivity of metal compound/carbon. Although the calcination under different atmospheres has been extensively studied, the transformation mechanism of PBA/MOF under hydrothermal conditions remains unclear. The qualitative preparation of P/MDCs in hydrothermal conditions remains a challenge. Here, we select PBA to construct a machine-learning model and measure its hydrothermal phase diagram. The architecture-activity relationship of substances among nine parameters was analyzed for the hydrothermal phase transformation of PBA. Excitingly, we established a universal qualitative model to accurately fabricate 31 PBA derivates. Additionally, we performed three-dimensional reconstructed transmission electron microscopy, X-ray absorption fine structure spectroscopy, ultraviolet photoelectron spectroscopy, in situ X-ray powder diffraction, and theoretical calculation to analyze the advantages of hydrothermal derivatives in the oxygen evolution reaction and clarify their reaction mechanisms. We uncover the unified principles of the hydrothermal phase transformation of PBA, and we expect to guide the design for a wide range of composites.

4.
Small ; 20(35): e2401713, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38693076

RESUMO

Aqueous zinc-based energy storage devices possess superior safety, cost-effectiveness, and high energy density; however, dendritic growth and side reactions on the zinc electrode curtail their widespread applications. In this study, these issues are mitigated by introducing a polyimide (PI) nanofabric interfacial layer onto the zinc substrate. Simulations reveal that the PI nanofabric promotes a pre-desolvation process, effectively desolvating hydrated zinc ions from Zn(H2O)6 2+ to Zn(H2O)4 2+ before approaching the zinc surface. The exposed zinc ion in Zn(H2O)4 2+ provides an accelerated charge transfer process and reduces the activation energy for zinc deposition from 40 to 21 kJ mol-1. The PI nanofabric also acts as a protective barrier, reducing side reactions at the electrode. As a result, the PI-Zn symmetric cell exhibits remarkable cycling stability over 1200 h, maintaining a dendrite-free morphology and minimal byproduct formation. Moreover, the cell exhibits high stability and low voltage hysteresis even under high current densities (20 mA cm-2, 10 mAh cm-2) thanks to the 3D porous structure of PI nanofabric. When integrated into full cells, the PI-Zn||AC hybrid zinc-ion capacitor and PI-Zn||MnVOH@SWCNT zinc-ion battery achieve impressive lifespans of 15000 and 600 cycles with outstanding capacitance retention. This approach paves a novel avenue for high-performance zinc metal electrodes.

5.
Langmuir ; 2024 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-39205649

RESUMO

The efficacy and structural evolution of Mo-doped titania nanoparticles (MTNPs) as advanced photocatalysts for degrading methyl blue (MB) are investigated by X-ray absorption spectroscopy (XAS). The 3 wt % MTNP, characterized by uniform size and anatase structure, exhibits higher efficiency. The spectral analyses unveiled structural variations in the TiO6 octahedral structure and revealed an active site of the distorted square pyramidal structure symmetry (C4v). The in situ XAS spectra illustrate that MTNPs, particularly at 3 wt % doping, effectively enhanced the hole carriers in Ti 3d orbitals with a charge transfer to Mo 4d orbitals and impeded electron-hole pair merging, significantly enhancing the photodegradation under light illumination. This study deepens our understanding of the crucial role of Mo doping in optimizing TiO2 nanoparticle performance for efficient environmental remediation, showcasing the potential of MTNPs as sustainable photocatalytic materials.

6.
Angew Chem Int Ed Engl ; : e202412077, 2024 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-39109496

RESUMO

Sub-nanoclusters with ultra-small particle sizes are particularly significant to create advanced energy storage materials. Herein, Sn sub-nanoclusters encapsulated in nitrogen-doped multichannel carbon matrix (denoted as Sn-SCs@MCNF) are designed by a facile and controllable route as flexible anode for high-performance potassium ion batteries (PIBs). The uniformly dispersed Sn sub-nanoclusters in multichannel carbon matrix can be precisely identified, which ensure us to clarify the size influence on the electrochemical performance. The sub-nanoscale effect of Sn-SCs@MCNF restrains electrode pulverization and enhances the K+ diffusion kinetics, leading to the superior cycling stability and rate performance. As freestanding anode in PIBs, Sn-SCs@MCNF manifests superior K+ storage properties, such as exceptional cycling stability (331 mAh g-1 after 150 cycles at 100 mA g-1) and rate capability. Especially, the Sn-SCs@MCNF||KFe[Fe(CN)6] full cell demonstrates impressive reversible capacity of 167 mAh g-1 at 0.4 A g-1 even after 200 cycles. Theoretical calculations clarify that the ultrafine Sn sub-nanoclusters are beneficial for electron transfer and contribute to the lower energy barriers of the intermediates, thereby resulting in promising electrochemical performance. Comprehensive investigation for the intrinsic K+ storage process of Sn-SCs@MCNF is revealed by in situ analysis. This work provides vital guidance to design sub-nanoscale functional materials for high-performance energy-storage devices.

7.
Angew Chem Int Ed Engl ; 63(7): e202317220, 2024 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-38153674

RESUMO

Modulating the microenvironment of single-atom catalysts (SACs) is critical to optimizing catalytic activity. Herein, we innovatively propose a strategy to improve the local reaction environment of Ru single atoms by precisely switching the crystallinity of the support from high crystalline and low crystalline, which significantly improves the hydrogen evolution reaction (HER) activity. The Ru single-atom catalyst anchored on low-crystalline nickel hydroxide (Ru-LC-Ni(OH)2 ) reconstructs the distribution balance of the interfacial ions due to the activation effect of metal dangling bonds on the support. Single-site Ru with a low oxidation state induces the aggregation of hydronium ions (H3 O+ ), leading to the formation of a local acidic microenvironment in alkaline media, breaking the pH-dependent HER activity. As a comparison, the Ru single-atom catalyst anchored on high-crystalline nickel hydroxide (Ru-HC-Ni(OH)2 ) exhibits a sluggish Volmer step and a conventional local reaction environment. As expected, Ru-LC-Ni(OH)2 requires low overpotentials of 9 and 136 mV at 10 and 1000 mA cm-2 in alkaline conditions and operates stably at 500 mA cm-2 for 500 h in an alkaline seawater anion exchange membrane (AEM) electrolyzer. This study provides a new perspective for constructing highly active single-atom electrocatalysts.

8.
Angew Chem Int Ed Engl ; : e202414650, 2024 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-39206502

RESUMO

Investigating the formation and transformation mechanisms of spiral-concave crystals holds significant potential for advancing innovative material design and comprehension. We examined the kinetics-controlled nucleation and growth mechanisms of Prussian Blue crystals with spiral concave structures, and constructed a detailed crystal growth phase diagram. The spiral-concave hexacyanoferrate (SC-HCF) crystals, characterized by high-density surface steps and a low stress-strain architecture, exhibit enhanced activity due to their facile interaction with reactants. Notably, the coordination environment of SC-HCF can be precisely modulated by the introduction of diverse metals. Utilizing X-ray absorption fine structure spectroscopy and in-situ ultraviolet-visible spectroscopy, we elucidated the formation mechanism of SC-HCF to Co-HCF facilitated by oriented adsorption-ion exchange (OA-IE) process. Both experimental data, and density functional theory confirm that Co-HCF possesses an optimized energy band structure, capable of adjusting the local electronic environment and enhancing the performance of the oxygen evolution reaction. This work not only elucidates the formation mechanism and coordination regulation for rich steps HCF, but also offers a novel perspective for constructing nanocrystals with intricate spiral-concave structures.

9.
Angew Chem Int Ed Engl ; 63(18): e202402018, 2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38390636

RESUMO

Developing ruthenium-based heterogeneous catalysts with an efficient and stable interface is essential for enhanced acidic oxygen evolution reaction (OER). Herein, we report a defect-rich ultrathin boron nitride nanosheet support with relatively independent electron donor and acceptor sites, which serves as an electron reservoir and receiving station for RuO2, realizing the rapid supply and reception of electrons. Through precisely controlling the reaction interface, a low OER overpotential of only 180 mV (at 10 mA cm-2) and long-term operational stability (350 h) are achieved, suggesting potential practical applications. In situ characterization and theoretical calculations have validated the existence of a localized electronic recycling between RuO2 and ultrathin BN nanosheets (BNNS). The electron-rich Ru sites accelerate the adsorption of water molecules and the dissociation of intermediates, while the interconnection between the O-terminal and B-terminal edge establishes electronic back-donation, effectively suppressing the over-oxidation of lattice oxygen. This study provides a new perspective for constructing a stable and highly active catalytic interface.

10.
J Am Chem Soc ; 145(43): 23659-23669, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37871168

RESUMO

Designing stable single-atom electrocatalysts with lower energy barriers is urgent for the acidic oxygen evolution reaction. In particular, the atomic catalysts are highly dependent on the kinetically sluggish acid-base mechanism, limiting the reaction paths of intermediates. Herein, we successfully manipulate the steric localization of Ru single atoms at the Co3O4 surface to improve acidic oxygen evolution by precise control of the anchor sites. The delicate structure design can switch the reaction mechanism from the lattice oxygen mechanism (LOM) to the optimized adsorbate evolution mechanism (AEM). In particular, Ru atoms embedded into cation vacancies reveal an optimized mechanism that activates the proton donor-acceptor function (PDAM), demonstrating a new single-atom catalytic pathway to circumvent the classic scaling relationship. Steric interactions with intermediates at the anchored Ru-O-Co interface played a primary role in optimizing the intermediates' conformation and reducing the energy barrier. As a comparison, Ru atoms confined to the surface sites exhibit a lattice oxygen mechanism for the oxygen evolution process. As a result, the delicate atom control of the spatial position presents a 100-fold increase in mass activity from 36.96 A gRu(ads)-1 to 4012.11 A gRu(anc)-1 at 1.50 V. These findings offer new insights into the precise control of single-atom catalytic behavior.

11.
Small ; 19(48): e2304200, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37525334

RESUMO

Molybdenum selenium (MoSe2 ) has tremendous potential in potassium-ion batteries (PIBs) due to its large interlayer distance, favorable bandgap, and high theoretical specific capacity. However, the poor conductivity and large K+ insertion/extraction in MoSe2 inevitably leads to sluggish reaction kinetics and poor structural stability. Herein, Coinduced engineering is employed to illuminate high-conductivity electron pathway and mobile ion diffusion of MoSe2 nanosheets anchored on reduced graphene oxide substrate (Co-MoSe2 /rGO). Benefiting from the activated electronic conductivity and ion diffusion kinetics, and an expanded interlayer spacing resulting from Co doping, combined with the interface coupling with highly conductive reduced graphene oxide (rGO) substrate through Mo-C bonding, the Co-MoSe2 /rGO anode demonstrates remarkable reversible capacity, superior rate capability, and stable long-term cyclability for potassium storage, as well as superior energy density and high power density for potassium-ion capacitors. Systematic performance measurement, dynamic analysis, in-situ/ex-situ measurements, and density functional theory (DFT) calculations elucidate the performance-enhancing mechanism of Co-MoSe2 /rGO in view of the electronic and ionic transport kinetics. This work offers deep atomic insights into the fundamental factors of electrodes for potassium-ion batteries/capacitors with superior electrochemical performance.

12.
Small ; 19(30): e2302238, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37191328

RESUMO

Developing efficient and durable electrocatalysts for the oxygen evolution reaction (OER) in proton exchange membrane (PEM) electrolyzers represents a significant challenge. Herein, the cobalt-ruthenium oxide nano-heterostructures are successfully synthesized on carbon cloth (CoOx /RuOx -CC) for acidic OER through a simple and fast solution combustion strategy. The rapid oxidation process endows CoOx /RuOx -CC with abundant interfacial sites and defect structures, which enhances the number of active sites and the charge transfer at the electrolyte-catalyst interface, promoting the OER kinetics. Moreover, the electron supply effect of the CoOx support allows electrons to transfer from Co to Ru sites during the OER process, which is beneficial to alleviate the ion leaching and over-oxidation of Ru sites, improving the catalyst activity and stability. As a self-supported electrocatalyst, CoOx /RuOx -CC displays an ultralow overpotential of 180 mV at 10 mA cm-2 for OER. Notably, the PEM electrolyzer using CoOx /RuOx -CC as the anode can be operated at 100 mA cm-2 stably for 100 h. Mechanistic analysis shows that the strong catalyst-support interaction is beneficial to redistribute the electronic structure of RuO bond to weaken its covalency, thereby optimizing the binding energy of OER intermediates and lowering the reaction energy barrier.

13.
Angew Chem Int Ed Engl ; 62(42): e202311937, 2023 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-37658707

RESUMO

Designing novel single-atom catalysts (SACs) supports to modulate the electronic structure is crucial to optimize the catalytic activity, but rather challenging. Herein, a general strategy is proposed to utilize the metalloid properties of supports to trap and stabilize single-atoms with low-valence states. A series of single-atoms supported on the surface of tungsten carbide (M-WCx , M=Ru, Ir, Pd) are rationally developed through a facile pyrolysis method. Benefiting from the metalloid properties of WCx , the single-atoms exhibit weak coordination with surface W and C atoms, resulting in the formation of low-valence active centers similar to metals. The unique metal-metal interaction effectively stabilizes the low-valence single atoms on the WCx surface and improves the electronic orbital energy level distribution of the active sites. As expected, the representative Ru-WCx exhibits superior mass activities of 7.84 and 62.52 A mgRu -1 for the hydrogen oxidation and evolution reactions (HOR/HER), respectively. In-depth mechanistic analysis demonstrates that an ideal dual-sites cooperative mechanism achieves a suitable adsorption balance of Had and OHad , resulting in an energetically favorable Volmer step. This work offers new guidance for the precise construction of highly active SACs.

14.
Curr Microbiol ; 79(7): 194, 2022 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-35579716

RESUMO

A Gram-positive-staining, strictly aerobic, motile, ellipsoidal endospore-forming bacterial strain, designated CHY01T, was isolated from the Chishui river in a section of Maotai Town, Guizhou Province, Southwest China. Strain CHY01T was found to grow optimally at pH 8.0 and 28 °C. The 16S rRNA gene sequence analysis indicated that strain CHY01T belonged to the genus Brevibacillus and clustered with the type strain of Brevibacillus panacihumi, with which it exhibited 16S rRNA gene sequence similarity values of 97.8%. The predominant respiratory quinone was MK-7, and the major polar lipids were phosphatidylethanolamine and phosphatidylglycerol. The major fatty acids were C14:0, iso-C15:0, anteiso-C15:0, C16:0, C15:1iso-H and/or C13:0 3-OH, and C16:1ω7c and/or C16:1ω6c. Genome sequencing revealed a genome size of 6.1 Mbp and a G + C content of 50.6%. The results of physiological and biochemical tests allowed strain CHY01T to be distinguished genotypically and phenotypically from Brevibacillus species with validly published names. Pairwise determined whole-genome average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values suggested that strain CHY01T represents a new species, for which we propose the name Brevibacillus dissolubilis sp. nov. with the type strain CHY01T (= CGMCC 1.15916 T = KCTC 33863 T).


Assuntos
Brevibacillus , Técnicas de Tipagem Bacteriana , Brevibacillus/genética , DNA Bacteriano/genética , Ácidos Graxos/química , Água Doce , Fosfolipídeos/química , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
15.
Angew Chem Int Ed Engl ; 61(12): e202116068, 2022 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-34957659

RESUMO

Oxygen reduction reaction (ORR) activity can be effectively tuned by modulating the electron configuration and optimizing the chemical bonds. Herein, a general strategy to optimize the activity of metal single-atoms is achieved by the decoration of metal clusters via a coating-pyrolysis-etching route. In this unique structure, the metal clusters are able to induce electron redistribution and modulate M-N species bond lengths. As a result, M-ACSA@NC exhibits superior ORR activity compared with the nanoparticle-decorated counterparts. The performance enhancement is attributed to the optimized intermediates desorption benefiting from the unique electronic configuration. Theoretical analysis reinforces the significant roles of metal clusters by correlating the ORR activity with cluster-induced charge transfer. As a proof-of-concept, various metal-air batteries assembled with Fe-ACSA@NC deliver remarkable power densities and capacities. This strategy is an effective and universal technique for electron modulation of M-N-C, which shows great potential in application of energy storage devices.

16.
Plant J ; 102(6): 1281-1293, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-31972869

RESUMO

Perturbation of lignin biosynthesis often results in severe growth and developmental defects in plants, which imposes practical limitations to genetic enhancement of lignocellulosic biomass for biofuel production. Currently, little information is known about the cellular and genetic mechanisms of this important phenomenon. Here we show that defects in both cell division and cell expansion underlie the dwarfism of an Arabidopsis lignin mutant ref8, and report the identification of a GROWTH INHIBITION RELIEVED 1 (GIR1) gene from a suppressor screen. GIR1 encodes an importin-beta-like protein required for the nuclear import of MYB4, a transcriptional repressor of phenylpropanoid metabolism. Disruption of GIR1 and MYB4 similarly alleviates the cellular defects and growth inhibition in ref8, suggesting that the growth rescue effect of gir1 is likely due to compromised MYB4 transport and function. Importantly, the phenylpropanoid perturbation is not alleviated in gir1 ref8 and myb4 ref8, suggesting that the function of MYB4 in growth inhibition of lignin-modified plants is likely to be distinct from its known role in transcriptional regulation of phenylpropanoid biosynthetic genes. This study also provides evidence that lignin-modification-induced dwarfism is not merely due to compromised water transport brought about by lignin deficiency, as gir1 has no effect on the growth inhibition of other lignin mutants that show the collapsed xylem phenotype.


Assuntos
Arabidopsis/crescimento & desenvolvimento , Lignina/metabolismo , beta Carioferinas/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/fisiologia , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/fisiologia , Divisão Celular , Regulação da Expressão Gênica de Plantas , Proteínas Repressoras/metabolismo , Proteínas Repressoras/fisiologia , Fatores de Transcrição/metabolismo , Fatores de Transcrição/fisiologia
17.
Small ; 17(10): e2007239, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33590684

RESUMO

Since the sluggish kinetic process of oxygen reduction (ORR)/evolution (OER) reactions, the design of highly-efficient, robust, and cost-effective catalysts for flexible metal-air batteries is desired but challenging. Herein, bimetallic nanoparticles encapsulated in the N-doped hollow carbon nanocubes (e.g., FeCo-NPs/NC, FeNi-NPs/NC, and CoNi-NPs/NC) are rationally designed via a general heat-treatment strategy of introducing NH3 pyrolysis of dopamine-coated metal-organic frameworks. Impressively, the resultant FeCo-NPs/NC hybrid exhibits superior bifunctional electrocatalytic performance for ORR/OER, manifesting exceptional discharging performance, outstanding lifespan, and prime flexibility for both Zn/Al-air batteries, superior to those of state-of-the-art Pt/C and RuO2 catalysts. X-ray absorption near edge structure and density functional theory indicate that the strong synergy between FeCo alloy and N-doped carbon frameworks has a distinctive activation effect on bimetallic Fe/Co atoms to synchronously modify the electronic structure and afford abundant dual-active Fe/Co-Nx sites, large surface area, high nitrogen doping level, and conductive carbon frameworks to boost the reversible oxygen electrocatalysis. Such N-doped carbon with bimetallic alloy bonds provides new pathways for the rational creation of high-efficiency energy conversion and storage equipment.

18.
Angew Chem Int Ed Engl ; 60(41): 22276-22282, 2021 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-34427019

RESUMO

Designing definite metal-support interfacial bond is an effective strategy for optimizing the intrinsic activity of noble metals, but rather challenging. Herein, a series of quantum-sized metal nanoparticles (NPs) anchored on nickel metal-organic framework nanohybrids (M@Ni-MOF, M=Ru, Ir, Pd) are rationally developed through a spontaneous redox strategy. The metal-oxygen bonds between the NPs and Ni-MOF guarantee structural stability and sufficient exposure of the surface active sites. More importantly, such precise interfacial feature can effectively modulate the electronic structure of hybrids through the charge transfer of the formed Ni-O-M bridge and then improves the reaction kinetics. As a result, the representative Ru@Ni-MOF exhibits excellent hydrogen evolution reaction (HER) activity at all pH values, even superior to commercial Pt/C and recent noble-metal catalysts. Theoretical calculations deepen the mechanism understanding of the superior HER performance of Ru@Ni-MOF through the optimized adsorption free energies of water and hydrogen due to the interfacial-bond-induced electron redistribution.

19.
Int J Syst Evol Microbiol ; 69(6): 1531-1536, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30204585

RESUMO

A Gram-stain-negative, non-motile, non-sporulating, rod-shaped, orange-pigmented bacterium, designated strain FQM01T, was isolated from a subterranean sediment sample in the Mohe permafrost area, China. Strain FQM01T grew optimally at 25 °C, pH 7.0 and NaCl concentration of 0 % (w/v). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain FQM01T belonged to the genus Sphingomonas. The closest phylogenetic relative was Sphingomonas spermidinifaciens GDMCC 1.657T (97.6 %), followed by Sphingomonas mucosissima DSM 17494T (97.2 %). The DNA G+C content of the isolate was 66.9 mol%. Strain FQM01T contained Q-10 as the predominant ubiquinone, and C18 : 1ω6c and/or C18 : 1ω7c, C16 : 1ω6c and/or C16 : 1ω7c, C16 : 0, C14 : 0 2-OH and C18 : 1ω7c 11 methyl as the major fatty acids. Major polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, sphingoglycolipid and an unidentified glycolipid. Only sym-homospermidine was detected as the polyamine. On the basis of phylogenetic and phenotypic data, strain FQM01T is considered to represent a novel species of Sphingomonas for which the name Sphingomonasfloccifaciens sp. nov. is proposed. The type strain is FQM01T (=CGMCC 1.15797T=KCTC 52630T).


Assuntos
Sedimentos Geológicos/microbiologia , Filogenia , Microbiologia do Solo , Sphingomonas/classificação , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Glicolipídeos/química , Fosfolipídeos/química , Pigmentação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Espermidina/análogos & derivados , Espermidina/química , Sphingomonas/isolamento & purificação , Ubiquinona/análogos & derivados , Ubiquinona/química
20.
Int J Syst Evol Microbiol ; 69(12): 3903-3909, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31498061

RESUMO

A Gram-reaction-negative, peach-brown-pigmented, slightly curved-rod-shaped, aerobic, non-motile bacterium, designated GSA243-2T, was isolated from fresh water samples collected from the Chishui River flowing through Maotai, Guizhou, south-west PR China. Phenotypic, chemotaxonomic and genomic traits were investigated. Results of phylogenetic analysis based on 16S rRNA gene sequences showed that the isolate belonged to the genus Rhodoferax. The closest phylogenetic relative was Rhodoferax saidenbachensis ATCC BAA-1852T (98.35 %). The major fatty acids were C16: 0 and C16 : 1ω6c and/or C16 : 1ω7c. The major respiratory quinone was ubiquinone Q-8 and the major polar lipid was phosphatidylethanolamine. Genome sequencing revealed a genome size of 3.67 Mbp and a G+C content of 61.17 mol%. Pairwise-determined whole genome average nucleotide identity values and digital DNA-DNA hybridization values suggested that strain GSA243-2T represents a new species, for which we propose the name Rhodoferaxbucti sp. nov. with the type strain GSA243-2T (=CGMCC 1.16288T=KCTC 62564T).


Assuntos
Comamonadaceae/classificação , Água Doce/microbiologia , Filogenia , Técnicas de Tipagem Bacteriana , Composição de Bases , China , Comamonadaceae/isolamento & purificação , DNA Bacteriano/genética , Ácidos Graxos/química , Hibridização de Ácido Nucleico , Fosfatidiletanolaminas/química , Pigmentação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/química
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