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1.
BMC Nephrol ; 25(1): 225, 2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-39009965

RESUMO

BACKGROUND: Membranous nephropathy (MN) is a common type of nephrotic syndrome (NS) in adults, accounting for about 20-30% of cases. Although secondary to specific factors, the coexistence of MN and mantle cell lymphoma (MCL) has been scarcely reported in clinical literature. CASE PRESENTATION: A 59-year-old Chinese male was admitted to the hospital with a generalized pruritic rash with bilateral lower extremity edema, which did not improve significantly after symptomatic treatment. He had undergone renal biopsy, and the diagnosis was thought to be secondary MN (SMN), therefore, we did a lymph node biopsy on the patient and found that MN was complicated with MCL. Soon after, the patient was admitted to the hematology department for a BR chemotherapy regimen (composed of bendamustine 90 mg/m2 BSA (body surface area), rituximab 375 mg/m2 BSA and dexamethasone 5 mg), and during the post-treatment follow-up, both his symptoms and renal function improved. CONCLUSIONS: The mechanism underlying the combination of SMN and MCL remains elusive and exceedingly rare, consequently often overlooked in clinical practice. This case serves to offer valuable clinical insights for diagnosis and treatment, while emphasizing the pivotal role of renal pathology in clinical assessment.


Assuntos
Exantema , Síndrome Nefrótica , Humanos , Masculino , Pessoa de Meia-Idade , Síndrome Nefrótica/complicações , Síndrome Nefrótica/diagnóstico , Síndrome Nefrótica/etiologia , Síndrome Nefrótica/tratamento farmacológico , Exantema/etiologia , Exantema/tratamento farmacológico , Linfoma de Célula do Manto/complicações , Linfoma de Célula do Manto/tratamento farmacológico , Linfoma de Célula do Manto/diagnóstico , Glomerulonefrite Membranosa/complicações , Glomerulonefrite Membranosa/diagnóstico , Glomerulonefrite Membranosa/tratamento farmacológico , Rituximab/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Dexametasona/uso terapêutico , Dexametasona/administração & dosagem , Cloridrato de Bendamustina/uso terapêutico , Cloridrato de Bendamustina/administração & dosagem
2.
Inorg Chem ; 60(3): 1716-1725, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33471502

RESUMO

Metal-organic frameworks (MOFs) and MOF-based composites as luminescent sensors with excellent economic practicability and handy operability have attracted much attention. Herein, we designed and fabricated a porous Zn-based MOF, [Zn(OBA)2(L1)·2DMA]n [1; H2OBA = 4,4'-oxybis(benzoic acid), L1 = 2,4,6-tris(4-pyridyl)pyridine, and DMA = N,N-dimethylacetamide], with mixed nodes under solvothermal conditions, and the pore size of 5.9 Å was calculated from N2 adsorption isotherms by using a density functional theory model. The as-synthesized compound 1 is stable in different boiling organic solvents and water solutions with a wide pH range of 2-12 and exhibits intense luminescence emission at 360 nm under excitation of 290 nm. Significantly, compound 1 shows high selective detection of Fe3+, CrO42-, and Cr2O72- in aqueous solution even under the interference of other ions. Compound 1 can quickly sense these ions in a short time and has a striking sensitivity toward Fe3+ with an ultralow limit of detection (LOD) of 1.06 µM. The relatively low LODs for CrO42- and Cr2O72- are 3.87 and 2.37 µM, respectively, compared to the reported works. Meanwhile, compound 1 can be reused to detect Fe3+, CrO42-, and Cr2O72- six times by simple regeneration. Considering the practicability, a mixed-matrix membrane (MMM) incorporated compound 1 and poly(methyl methacrylate) has been constructed. This MMM displays quick detection of Fe3+, CrO42-, and Cr2O72- and prompt regeneration by lifting from the analyte. This useful MMM shows a comparable LOD below 4.35 µM for these ions. This work presents a cost-effective Zn-based MOF as a functional platform for simple but useful sensing of Fe3+, CrO42-, and Cr2O72- in aqueous solution.

3.
Chemistry ; 26(62): 14187-14193, 2020 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-32779769

RESUMO

Here, a porous cobalt-organic framework with pillared layer structures, namely [Co3 OBA3 PTD(H2 O)2 ⋅ 2 DMA⋅H2 O]n (1, H2 OBA=4,4'-oxybis(benzoic acid); PTD=6-(pyridin-4-yl)-1,3,5-triazine-2,4-diamine), was fabricated by using cobalt trinuclear nodes, low-cost carboxylic linker, and accessible nitrogen heterocyclic ligands. This compound exhibited a highly efficient solvatochromism towards CH2 Cl2 within one minute and can be used 200 times at least. The corresponding dropper detector was assembled as a practical sensor. Meanwhile, the porous Co3 O4 was obtained by a simple but effective annealing treatment. Electrochemical measurements confirm that this Co3 O4 material derived from compound 1 shows high and stable lithium storage capabilities (1081.75 mA h g-1 at 200 mA g-1 after 115 cycles) and excellent rate properties.

4.
J Comput Chem ; 39(27): 2324-2332, 2018 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-30238601

RESUMO

The mechanism of N-Bromosuccinimide (NBS) promoted synthesis of imidazo[1,2-a]pyridine in water as well as the effective activation modes of NBS was investigated by Density Functional Theory (DFT) calculations. Two main mechanisms that differ in the reaction sequence of substrate were explored: styrene with NBS then followed by 2-aminopyridine (M1) or simultaneously with NBS and 2-aminopyridine (M2), and water-assisted M2 is the more favored one. We found that the adding sequence of 2-aminopyridine affects profoundly on the title reaction. Moreover, upon the assistance of water and NBS, the preferential mechanistic scenario involves three major processes: nucleophilic addition, stepwise H-shift and intramolecular cyclization, three-step deprotonation, rather than a classical bromonium ion species. Specifically, the cooperative interaction of NBS and water plays a critical role in the title reaction. Water acts as solvent, reactant, anchoring, stabilizer, and catalyst. NBS promotes the above three processes by the effective forms of Br+ /Br- , succinimide, and its ethanol isomer. Furthermore, noncovalent interactions between catalysts and substrates are responsible for the different reactive activities of M1 and M2. Our results indicate that simultaneous adding of all reactants is recommended toward economical synthesis. © 2018 Wiley Periodicals, Inc.

5.
Chemistry ; 24(72): 19152-19155, 2018 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-30281173

RESUMO

A stable hex-type metal-organic framework (MOF, WMOF-1) was constructed by nano-sized [MnII 18 ] metallamacrocycle secondary building unit, being the one with the highest nuclearity of manganese wheel-like node in the microporous MOF. WMOF-1 displays an effective gas adsorption and the antiferromagnetic behavior.

6.
Chemistry ; 24(8): 1962-1970, 2018 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-29178323

RESUMO

Polymetallic complexes with interesting multifunctions have attracted extensive investigation. Synthesized through the use of different cobalt salt anions and solvents, five complexes, namely [CoII4 CoIII3 (H2 L)3 Cl5 (MeOH)] (1), [CoII4 CoIII3 (H2 L)3 (CH3 COO)4 (HCOO)⋅H2 O]n (2), [CoII4 CoIII3 (H2 L)3 (HCOO)4 (NO3 )⋅2H2 O]n (3), [CoII4 CoIII3 (H2 L)3 (bda)(CH3 COO)4 ⋅2H2 O]n (4), and [CoII4 CoIII3 (H2 L)3 (ipa)(HCOO)3 (dmf)⋅H2 O]n (5) (H6 L=bis-tris propane; BDA=biphenyl-4,4'-dicarboxylic acid; IPA=isophthalic acid; DMF=N,N-dimethylformamide), based on the heptanuclear {CoII4 CoIII3 } cluster with structures from 0D to 3D metal-organic frameworks (MOFs) have been solvothermally synthesized. Compound 1 is the first 0D heptanuclear cluster based on H6 L. Compound 2 crystallizes in the chiral space group P21 21 21 and consists of a 1D chiral helical chain. Complex 3 exhibits a 3D network structure. Compound 4 possesses a 1D zigzag-like chain structure. Finally, compound 5 was obtained as a 3D microporous structure. Compounds 1, 3, and 4 display dominant ferrimagnetic interactions whereas compounds 2 and 5 exhibit antiferromagnetic interactions. Moreover, the Co3 O4 prepared by calcining compound 2 presents a reversible capacity of 1122.9 mA h g-1 at 0.2 A g-1 after 100 cycles and an excellent rate capability, which suggests that coordination compounds with a 1D chain structure are outstanding precursors for preparing anode materials for lithium ion batteries.

7.
Sensors (Basel) ; 18(5)2018 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-29747419

RESUMO

Dempster⁻Shafer evidence theory is widely applied in various fields related to information fusion. However, how to avoid the counter-intuitive results is an open issue when combining highly conflicting pieces of evidence. In order to handle such a problem, a weighted combination method for conflicting pieces of evidence in multi-sensor data fusion is proposed by considering both the interplay between the pieces of evidence and the impacts of the pieces of evidence themselves. First, the degree of credibility of the evidence is determined on the basis of the modified cosine similarity measure of basic probability assignment. Then, the degree of credibility of the evidence is adjusted by leveraging the belief entropy function to measure the information volume of the evidence. Finally, the final weight of each piece of evidence generated from the above steps is obtained and adopted to modify the bodies of evidence before using Dempster’s combination rule. A numerical example is provided to illustrate that the proposed method is reasonable and efficient in handling the conflicting pieces of evidence. In addition, applications in data classification and motor rotor fault diagnosis validate the practicability of the proposed method with better accuracy.

8.
Implant Dent ; 27(5): 555-563, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30134266

RESUMO

PURPOSE: To investigate the effect(s) of screw-access hole (SAH) in different diameters on the cement-retained implant prosthodontic systems and surrounding cortical bones. MATERIALS AND METHODS: Twenty finite element models were divided into 4 groups: 2 types of full-contour (FC) crowns (Y-TZP, gold alloy) and 2 types of porcelain-fused-to-metal crowns (based on Co-Cr, Au-Pd alloy). For each group, 5 crowns were simulated by varying the diameter of SAH (0, 1, 2, 3, and 4 mm). A vertical load of 200 N and an oblique load of 100 N (45°s) were applied. All models were analyzed with finite element analysis software. RESULTS: The stress on the occlusal surface of crowns was almost unchanged when the SAH was within 0 to 3 mm, whereas it showed an obvious increase when it reached 4 mm. The stress concentration was also suddenly changed from the loading area to the hole margin under vertical loading. As for the screw, a lower stress level was observed in vertical loading when an FC crown with an SAH within 0 to 1 mm was applied. The stress concentration was constantly located at the beginning of the first thread. Stresses of other components remained almost unchanged. CONCLUSIONS: From the aspect of biomechanics, an FC crown with a 1-mm access hole is recommended when a combined cement- and screw-retained crown was used in the posterior region.


Assuntos
Coroas , Cimentos Dentários/uso terapêutico , Projeto do Implante Dentário-Pivô , Implantes Dentários , Prótese Dentária Fixada por Implante , Adulto , Fenômenos Biomecânicos , Osso Cortical/patologia , Análise do Estresse Dentário , Análise de Elementos Finitos , Humanos , Masculino , Mandíbula/patologia
9.
J Colloid Interface Sci ; 670: 272-278, 2024 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-38763023

RESUMO

Exploring effective strategies for developing new high-efficiency catalysts for water splitting is essential for advancing hydrogen energy technology. Herein, Co3O4/RuO2 heterojunction interface is construct through ion exchange reaction and pyrolysis. The as-synthesized Co3O4/RuO2-4 exhibits outstanding oxygen evolution reaction (OER) activity at the current density of 100 mA cm-2 with a low overpotential of 276 mV, and remarkable stability (maintaining activity for 60 h at 100 mA cm-2). Experimental results and theoretical calculations reveal that the electrons around the heterogeneous interface transferred from RuO2 to Co3O4, resulting in electron redistribution and optimization of energy barriers for OER intermediates. This unique composite catalyst structure offers a new potential for designing efficient oxygen electrocatalysts at large current density.

10.
J Org Chem ; 78(24): 12629-36, 2013 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-24236578

RESUMO

The one-pot and direct synthesis of 7,9-dialkylpurin-8-one analogues with broad substrate scope has been developed. This copper-catalyzed C-H oxidation reaction could avoid multistep synthesis of quaternary ammonium salts and expand the scope of halogenated alkanes. Moreover, benzimidazole derivatives are also applicable in the catalytic system.


Assuntos
Purinas/síntese química , Alcanos/química , Catálise , Cobre/química , Iodetos/química , Estrutura Molecular , Oxirredução , Purinas/química , Compostos de Amônio Quaternário/química
11.
PLoS One ; 18(9): e0291091, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37729323

RESUMO

Citizens' attitudes towards foreign countries are considered an important factor in making foreign policy. This also holds in China, where public opinion is given significant weight in foreign policy-making. On the other hand, the media serves as a gateway for citizens to access the outside world, shaping their attitudes towards foreign countries. The rise of the Internet since the mid-2000s has brought about radical changes in the media landscape. The Internet, characterized by its loose control and the strong patriotic sentiment among netizens, is viewed as a breeding ground for popular nationalism. Scholars and analysts worry that the prevalence of online popular nationalism may lead to xenophobia and hostility towards Western countries portrayed as out-group others in this narrative. This study aims to investigate the impact of popular nationalism narratives flooding the Internet on citizens' attitudes, and the differential influence of the Internet compared to traditional mass media. Furthermore, this study also examines the dynamics of citizens' foreign attitudes and the role of media channels in shaping these attitudes. Through a quantitative analysis based on the data collected in 2010 and 2020, the study challenges concerns about xenophobic sentiments resulting from online nationalism, finding them to be unnecessary. Additionally, this study also discovers that, compared to traditional mass media, the influence of the Internet on attitude is more open to change in the international environment.


Assuntos
Atitude , População do Leste Asiático , Internet , Opinião Pública , Humanos
12.
J Agric Food Chem ; 71(22): 8425-8436, 2023 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-37233613

RESUMO

At present, most of the research on coix seed polyphenols (CSPs) focuses on the separation, purification, structure analysis, and biological functions of specific components, and few studies have considered the overall bioavailability and the metabolites that play a role after digestion and absorption and their biological functional activities. In this study, we constructed a MKN28 and Caco-2 cell monolayer continuous transport model (MCTM) to study the bioavailability of CSPs in the digestion and absorption stages of the stomach and small intestine. Using this model, we innovatively divided CSPs into easy-to-digest and hard-to-digest polyphenols and studied their intracellular lipid-lowering function and their influence on human intestinal flora. Transwell experiments showed that ferulic acid, rutin, naringin, arbutin, and syringetin had high transmembrane transport efficiency, especially syringetin. The methylation reaction in the monolayer membrane of Caco-2 cells may be the reason for the higher transport rate of syringetin. Further experiments showed that CPL reduced TG accumulation by more than 50% during 3T3-L1 differentiation and promoted the transformation of adipocytes into brown cells (p < 0.05). Finally, in vitro fermentation experiments showed that CSP_AP can increase the abundance of Lactobacillus and Bifidobacterium of human gut microbiota at the genus level (p < 0.05).


Assuntos
Coix , Polifenóis , Animais , Camundongos , Humanos , Polifenóis/farmacologia , Polifenóis/metabolismo , Células CACO-2 , Células 3T3-L1 , Disponibilidade Biológica , Diferenciação Celular , Sementes , Lipídeos , Adipócitos/metabolismo
13.
Food Res Int ; 155: 111101, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35400474

RESUMO

Rapeseed napin (Brassica napus) protein-derived hydrolysates (RNPHs, 1-4) are mixtures of peptides, prior to reaching liver tissue and playing their antidiabetic role, at least being absorbed and metabolized by the intestinal barrier. The study aims at screening and identifying high bioavailable rapessed napin-derived oligopeptides via simulated gastrointestinal digestion and absorption. Specifically, RNPHs were obtained using a novel ultrasound-assisted digestive device. The potential capacity of treating type 2 diabetes mellitus (T2DM) was evaluated preliminarily via enhancing glucose transporter 4 (GLUT4) expression and translocation. Also, absorbable rapeseed napin-derived oligopeptides were screened and identified in a Caco-2/HepG2 co-culture model using liquid chromatography coupled with electrospray ionisation and quadrupole time of flight tandem mass spectrometry (LC-ESI-QTOF-MS). The results involved mainly two aspects. First, absorbable oligopeptides from RNPH-1 (Molecular weight, Mw ≤ 3 kDa) with the highest degree of hydrolysis (DH) were the optimal ones to enhance GLUT4 expression and translocation (P < 0.05). Secondly, oligopeptides (Thr-His-Leu-Pro-Lys (THLPK), His-Leu-Pro-Lys (HLPK), (Ile) Leu-Pro-Lys ((I)LPK), His-Leu-Lys (HLK), and Leu-His-Lys (LHK)), identified from both RNPH-1 and RNPH-2 which significantly enhanced GLUT4 expression and translocation, could be absorbed intact and reached HepG2 cells. These findings indicated that high bioavailable oligopeptides from RNPHs were the potential usefulness to treat T2DM in vitro.


Assuntos
Brassica napus , Brassica rapa , Diabetes Mellitus Tipo 2 , Células CACO-2 , Técnicas de Cocultura , Humanos , Oligopeptídeos/química , Hidrolisados de Proteína/química , Espectrometria de Massas em Tandem
14.
Front Immunol ; 13: 941830, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36159870

RESUMO

The gut microbiome is an essential component of the intestinal mucosal barrier, critical in regulating intestinal permeability. Microbiome dysbiosis and intestinal permeability changes are commonly encountered conditions in patients with cirrhosis and are closely related to its development and further complications. However, alterations in the gut microbiome and intestinal permeability in chronic hepatitis B virus (HBV) patients with cirrhotic portal hypertension after undergoing a splenectomy plus pericardial devascularization (SPD) have not been investigated. This study recruited 22 patients who were measured against themselves on the study parameters before and after an SPD, along with 20 healthy controls. Methodologically, fecal samples were collected for gut microbiome analysis by 16S ribosomal DNA sequencing, and peripheral blood samples were obtained to examine the liver function and intestinal permeability. This study showed that the community structure of the gut microbiomes in patients before the SPD exhibited obvious differences from those in the healthy control group. They also exhibited a decreased bacterial community richness, increased intestinal permeability, and enhanced inflammation compared with the healthy controls. These issues were further aggravated two weeks after the SPD. There was also evidence of significantly higher abundances of Streptococcaceae, Enterobacteriaceae, and Enterococcaceae than those in the healthy control group. However, 12 months after the surgery, 12 of the 16 patient-associated genera recovered, of which 10 reached normal levels. Additionally, the microbiome diversity increased; the bacterial composition was back to a level similar to the healthy controls. Liver function, intestinal permeability, and inflammation levels all improved compared with preoperative levels. Furthermore, correlation analyses indicated that the five recovered bacterial taxa and the Shannon diversity index were correlated with several improved clinical indicators. Altogether, the improvements in the liver function and intestinal permeability in HBV-related cirrhotic patients may be related to the restoration of the gut microbiome after an SPD.


Assuntos
Microbioma Gastrointestinal , Hepatite B Crônica , Hipertensão Portal , Bactérias , Vírus da Hepatite B , Hepatite B Crônica/complicações , Humanos , Hipertensão Portal/etiologia , Hipertensão Portal/cirurgia , Inflamação/complicações , Cirrose Hepática/complicações , Permeabilidade , Esplenectomia/efeitos adversos
15.
Aging (Albany NY) ; 13(17): 20906-20914, 2021 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-34499050

RESUMO

BACKGROUND: Cardiac injury is common and associated with poor clinical outcomes in COVID-19. Data are lacking whether high-dose intravenous vitamin C (HIVC) could help to ameliorate myocardial injury in the pandemic. METHODS: The retrospective cohort study included consecutive severe and critically ill COVID-19 patients with cardiac injury receiving symptomatic supportive treatments alone or together with HIVC. Troponin I and inflammatory markers were collected at admission and day 21 during hospitalization from the electronic medical records. RESULTS: The patients (n = 113) were categorized into the ameliorated cardiac injury (ACI) group (n = 70) and the non-ameliorated cardiac injury (NACI) group (n = 43). Overall, fifty-one (45.1%) patients were administered with HIVC, the percentages of patients with HIVC were higher in the ACI group than those in the NACI group. Logistic regression analysis revealed that HIVC was independently associated with the improvement of myocardial injury. Further analysis showed that inflammatory markers levels significantly decreased at day 21 during hospitalization in patients with HIVC therapy compared to those administered with symptomatic supportive treatments alone. Meanwhile, similar results were also observed regarding changes in inflammatory markers levels from baseline to day 21 during hospitalization in the patients treated with HIVC. CONCLUSIONS: HIVC can ameliorate cardiac injury through alleviating hyperinflammation in severe and critically ill patients with COVID-19.


Assuntos
Ácido Ascórbico/uso terapêutico , Tratamento Farmacológico da COVID-19 , COVID-19/epidemiologia , Traumatismos Cardíacos/tratamento farmacológico , Pandemias , Idoso , Biomarcadores/sangue , COVID-19/sangue , Relação Dose-Resposta a Droga , Feminino , Hospitalização , Humanos , Inflamação/patologia , Mediadores da Inflamação/sangue , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Troponina I/metabolismo
16.
Dalton Trans ; 48(1): 296-303, 2018 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-30516197

RESUMO

Two new 3D cobalt metal-organic frameworks (MOFs), [Co4(CH3COO)(in)5(µ3-OH)2]·2H2O (1) and [Co4(SO4)2(in)4(DMF)2]·3DMF (2) (Hin = isonicotinic acid), have been prepared through the anion template method. Compound 1 consists of rare odd-number connected (9-connected) cubane-like SBUs, while compound 2 consists of 8-connected high-symmetry square-planar clusters. Magnetic studies indicate that compound 1 exhibits spin-canting antiferromagnetic ordering, while compound 2 shows antiferromagnetic behavior. At 273 K and 1 bar, compound 1 exhibits a high CO2 selectivity over CH4 and a significant CO2 uptake of 13.6 wt%, which is higher than that of 2 (8.5 wt%). Furthermore, compound 1 was then transformed into ultrasmall Co3O4 nanoparticles via simple but effective annealing treatment. Electrochemical measurements show that the Co3O4 nanospheres derived from compound 1 exhibited high and stable lithium storage properties (1100 mA h g-1 after 100 cycles at 200 mA g-1) and excellent rate capabilities.

17.
Dalton Trans ; 47(24): 7934-7940, 2018 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-29808888

RESUMO

The chiral Zn(ii) metal-organic framework [(CH3)2NH2]5[Zn1.5(Zn3O)(TATAT)2]·9DMF·17H2O (1) has been prepared from achiral precursors Zn(NO3)2·6H2O and 5,5',5''-(1,3,5-triazine-2,4,6-triyl)tris(azanediyl)triisophthalate (H6TATAT) in a solvent mixture of DMF/MeOH/H2O/HCOOH without any chiral sources. In particular, the non-random handedness excess (1P ≫ 1M) was generated and was verified by single-crystal X-ray diffraction and solid-state circular dichroism spectroscopy. Furthermore, complex 1 displays high selectivity and sensitivity for detecting Fe3+ and is found to be an excellent chemical sensor for detecting nitro explosives especially 3-nitrophenol.

18.
Nanoscale ; 10(10): 4872-4881, 2018 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-29473928

RESUMO

Herein, a novel non-platinum core-shell catalyst, namely, IrNi@PdIr/C was prepared via a galvanic replacement reaction; it exhibits enhanced hydrogen oxidation activity and excellent stability under alkaline conditions. Electrochemical experiments demonstrated that the mass and specific activities at 50 mV of IrNi@PdIr/C are 2.1 and 2.2 times that of commercial Pt/C in 0.1 M KOH at 298 K, respectively. Moreover, accelerated degradation tests have shown that the electrochemically active surface area (ECSA) of IrNi@PdIr/C reduces by only 5.1%, which is almost 4 times less than that of commercial Pt/C and the mass activity at 50 mV of IrNi@PdIr/C after 2000 potential cycles is still 1.8 times higher than that of aged Pt/C. XRD and XPS analysis suggest that the enhanced HOR activity is attributed to the weakening of the hydrogen binding to the PdIr overlayers induced by the IrNi core. The better stability to potential cycling can be associated with the PdIr shell, which inhibits oxide formation. These results suggest that IrNi@PdIr/C is a promising non-platinum anode catalyst for alkaline anion exchange membrane fuel cells.

19.
RSC Adv ; 8(23): 12887-12893, 2018 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-35541256

RESUMO

A novel cathode architecture using vertically aligned Co nanoneedle arrays as an ordered support for application in alkaline anion-exchange membrane fuel cells (AAEMFCs) has been developed. The Co nanoneedle arrays were directly grown on a stainless steel sheet via a hydrothermal reaction and then a Pd layer was deposited on the surface of the Co nanoneedle arrays using a vacuum sputter-deposition method to form Pd/Co nanoneedle arrays. After transferring the Pd/Co nanoneedle arrays to an AAEM, a cathode catalyst layer was formed. Without the use of an alkaline ionomer, the AAEMFC with the prepared cathode catalyst layer showed an enhanced performance with ultra-low Pd loading of down to 33.5 µg cm-2, which is much higher than the conventionally used cathode electrode with a Pt loading of 100 µg cm-2. This is the first report where three-dimensional Co nanoneedle arrays have been used as the cathode support in an AAEMFC, which is able to deliver a higher power density without an alkaline ionomer than that of conventional membrane electrode assembly (MEA).

20.
ACS Appl Mater Interfaces ; 9(1): 464-471, 2017 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-27966878

RESUMO

Employing a low-cost and highly efficient electrocatalyst to replace Ir-based catalysts for oxygen evolution reaction (OER) has drawn increasing interest in renewable energy storage. In this work, a vertically aligned FeOOH/NiFe layered double hydroxides (LDHs) nanosheets supported on Ni foam (VA FeOOH/NiFe LDHs-NF) is prepared as a highly effective OER electrode in alkaline electrolyte. The VA FeOOH/NiFe LDHs-NF represents nanosheet arrays on nickel foam with some interspace among them. The vertically aligned and interlayer-structured architecture is binder-free and contributes to facile strain relaxation, relieving the exfoliation of the catalysts layer caused by the oxygen evolution process. The as-prepared electrode shows current densities of 10 and 500 mA cm-2 at overpotentials of 208 and 288 mV, and good stability in a half-cell electrolyzer. Besides, the alkaline polymer electrolyte water electrolyzer (APEWE) with this electrode showed 1.71 V at 200 mA cm-2, and 2.041 V at 500 mA cm-2, exhibiting the corresponding energy efficiency of 86.0% and 72.0% (based on the lower heating value of hydrogen), which is better than the typical commercial alkaline water electrolyzer.

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