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1.
Diagnostics (Basel) ; 13(24)2023 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-38132241

RESUMO

This manuscript discusses a rare case of acute appendicitis caused by metastasis from invasive breast carcinoma of no special type in a 70-year-old female previously diagnosed with breast cancer. It delves into the diagnostic challenges and management complexities of such unusual clinical presentations. The paper includes an analysis of 19 documented cases, enriching the understanding of metastatic patterns and treatment strategies in breast cancer. It underlines the importance of considering a history of malignancy when diagnosing acute abdominal conditions and emphasizes a comprehensive approach in interpreting diagnostic imaging in patients with past oncological issues to effectively manage metastatic breast cancer exhibiting atypical manifestations.

2.
Open Med (Wars) ; 18(1): 20230859, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38152329

RESUMO

Intensive care units (ICUs) are expert hospital areas that provide treatment and 24 h care for people who are very sick. Sepsis represents a serious, severe condition and it can lead to septic shock and multiple organ dysfunction syndromes and is one of the most common reasons for patients' hospitalization in ICUs. We wanted to explore the prognostic values of interleukin (IL) 33, soluble suppression of tumorigenicity 2 (sST2), IL 27, and galectin 3 in critically-ill patients. We assumed that these parameters in combination or alone could predict mortality in ICU patients. This research represents a clinical non-randomized prospective study, performed at the Medical Military Academy, a tertiary care hospital in Belgrade, Serbia. The patients were divided in four groups: patients with sepsis (peritonitis, pancreatitis, trauma) and patients without sepsis (trauma). Total number of patients enrolled in the study was 151 and average years of patients were 56.48. The values greater than the cut-off were the predictors of mortality. The IL-33, IL-27 as well as galectin-3 can successfully predict the outcome of critically-ill patients in ICUs. The sST2, cannot predict death in critically-ill patients as a single prognostic factor. However, the combination of at least two biomarkers: IL-33, sST2, IL-27, and galectin-3, gives very significant results in predicting the outcome in patients admitted to ICUs.

3.
Medicina (Kaunas) ; 59(11)2023 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-38003957

RESUMO

Strokes are one of the global leading causes of physical or mental impairment and fatality, classified into hemorrhagic and ischemic strokes. Ischemic strokes happen when a thrombus blocks or plugs an artery and interrupts or reduces blood supply to the brain tissue. Deciding on the imaging modality which will be used for stroke detection depends on the expertise and availability of staff and the infrastructure of hospitals. Magnetic resonance imaging provides valuable information, and its sensitivity for smaller infarcts is greater, while computed tomography is more extensively used, since it can promptly exclude acute cerebral hemorrhages and is more favorable speed-wise. The aim of this article was to give information about the neuroimaging modalities used for the diagnosis and monitoring of ischemic strokes. We reviewed the available literature and presented the use of computed tomography, CT angiography, CT perfusion, magnetic resonance imaging, MR angiography and MR perfusion for the detection of ischemic strokes and their monitoring in different phases of stroke development.


Assuntos
AVC Isquêmico , Acidente Vascular Cerebral , Humanos , AVC Isquêmico/complicações , Acidente Vascular Cerebral/diagnóstico por imagem , Acidente Vascular Cerebral/etiologia , Neuroimagem/efeitos adversos , Neuroimagem/métodos , Imageamento por Ressonância Magnética/efeitos adversos , Tomografia Computadorizada por Raios X/métodos
4.
Diagnostics (Basel) ; 13(12)2023 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-37371019

RESUMO

Chest X-ray has verified its role as a crucial tool in COVID-19 assessment due to its practicability, especially in emergency units, and Brixia score has proven as a useful tool for COVID-19 pneumonia grading. The aim of our study was to investigate correlations between main laboratory parameters, vaccination status, and Brixia score, as well as to confirm if Brixia score is a significant independent predictor of unfavorable outcome (death) in COVID-19 patients. The study was designed as a cross-sectional multicentric study. It included patients with a diagnosed COVID-19 infection who were hospitalized. This study included a total of 279 patients with a median age of 62 years. The only significant predictor of unfavorable outcome (death) was Brixia score (adjusted odds ratio 1.148, p = 0.022). In addition, the results of the multiple linear regression analysis (R2 = 0.334, F = 19.424, p < 0.001) have shown that male gender (B = 0.903, p = 0.046), severe COVID-19 (B = 1.970, p < 0.001), and lactate dehydrogenase (B = 0.002, p < 0.001) were significant positive predictors, while albumin level (B = -0.211, p < 0.001) was a significant negative predictor of Brixia score. Our results provide important information about factors influencing Brixia score and its usefulness in predicting the unfavorable outcome (death) of COVID-19 patients. These findings have clinical relevance, especially in epidemic circumstances.

5.
PLoS One ; 17(1): e0263015, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35081161

RESUMO

Problem-based learning (PBL) allows students to learn medical statistics through problem solving experience. The aim of this study was to assess the efficiency of PBL modules implemented in the blended learning courses in medical statistics through knowledge outcomes and student satisfaction. The pilot study was designed as a randomized controlled trial that included 53 medical students who had completed all course activities. The students were randomized in two groups: the group with access to PBL modules within the blended learning course (hPBL group) and the group without access to PBL modules-only blended learning course (BL group). There were no significant differences between the groups concerning socio-demographic characteristics, previous academic success and modality of access to course materials. Students from hPBL group had a significantly higher problem solving score (p = 0.012; effect size 0.69) and the total medical statistics score (p = 0,046; effect size 0.57). Multivariate regression analysis with problem solving as an outcome variable showed that problem solving was associated with being in hPBL group (p = 0.010) and having higher grade point average (p = 0.037). Multivariate regression analysis with the medical statistics score as an outcome variable showed the association between a higher score on medical statistics with access to PBL modules (p = 0.045) and a higher grade point average (p = 0.021). All students in hPBL group (100.0%) considered PBL modules useful for learning medical statistics. PBL modules can be easily implemented in the existing courses within medical statistics using the Moodle platform, they have high applicability and can complement, but not replace other forms of teaching. These modules were shown to be efficient in learning, to be well accepted among students and to be a potential missing link between teaching and learning medical statistics. The authors of this study are planning to create PBL modules for advanced courses in medical statistics and to conduct this study on other universities with a more representative study sample, with the aim to overcome the limitations of the existing study and confirm its results.


Assuntos
Bioestatística , Educação Médica , Aprendizagem Baseada em Problemas , Estudantes de Medicina , Feminino , Humanos , Masculino , Projetos Piloto
6.
Expert Rev Neurother ; 21(11): 1283-1301, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34633254

RESUMO

INTRODUCTION: Disease-specific treatments are available only for a minority of patients with genetic epilepsies, while the rest are treated with anticonvulsants, which are ineffective in almost one-third of patients. AREAS COVERED: Recently approved and the most effective emerging therapeutics under development for the treatment of genetic epilepsies are overviewed after systematic search and analysis of relevant literature. EXPERT OPINION: New and emerging drugs for genetic epilepsies exploit one of the two approaches: inhibiting hyperactive brain foci through blocking excitatory or augmenting inhibitory neurotransmission, or correcting the underlying genetic defect. The first is limited by insufficient selectivity of available compounds, and the second by imperfection of currently used vectors of genetic material, unselective and transient transgene expression. Besides, the treatment may come too late, after structural abnormalities and epilepsy deterioration takes place. However, with recent improvements, we can expect to see soon gradual decline in the number of patients with therapy-resistant genetic epilepsies.


Assuntos
Epilepsia , Anticonvulsivantes/uso terapêutico , Epilepsia/tratamento farmacológico , Epilepsia/genética , Humanos
7.
Medicina (Kaunas) ; 57(10)2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34684089

RESUMO

Background and Objectives: Although vitamin D insufficiency or deficiency is prevalent in children with allergic diseases, recommendations for supplementation dosing regimens are imprecise and variable in the literature, because clinical trials aiming to determine optimal doses were scarce in the past. This study aimed to investigate supplementation of vitamin D3 that may achieve therapeutically effective but not toxic serum levels in a subpopulation of children with allergic diseases and concomitant hypovitaminosis D. Materials and Methods: The retrospective, observational study with a cross-sectional design included 94 children suffering from allergic diseases and having vitamin D deficiency/insufficiency who were prescribed high-dose vitamin D3 supplementation by a pediatrician for at least 6 weeks and not more than 9 weeks. Serum levels of the major metabolite of vitamin D (25-(OH)D) were determined in all children twice: before and two weeks after the end of vitamin D3 supplementation. Results: An increase in serum level of the 25-(OH)D after supplementation was significant. However, if the subjects had higher serum levels of the 25-(OH)D before the supplementation, and if the supplementation lasted 8 instead of 6 weeks, the absolute increase in serum level of the 25-(OH)D was lower. Patients taking corticosteroids as inhalation or intranasally had a more intense effect of vitamin D3 supplementation, i.e., the absolute increase in levels of 25-(OH)D was higher than in patients not using such medication. Conclusions: Vitamin D deficiency and insufficiency in children with allergic diseases can be treated with maximal recommended doses of vitamin D3 for a short period of time, especially if they were prescribed with inhalation or intranasal corticosteroids.


Assuntos
Hipersensibilidade , Deficiência de Vitamina D , Criança , Colecalciferol/uso terapêutico , Estudos Transversais , Suplementos Nutricionais , Humanos , Hipersensibilidade/complicações , Hipersensibilidade/tratamento farmacológico , Estudos Retrospectivos , Vitamina D , Deficiência de Vitamina D/complicações , Deficiência de Vitamina D/tratamento farmacológico
8.
Pharm Pat Anal ; 10(3): 165-173, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-34076528

RESUMO

Focal epilepsy is one of the most frequent specific type of epilepsies, with 30% treatment-resistant patients. There are several directions researchers can follow to improve existing treatment of focal epilepsy: synthesis of new compounds with anticonvulsant activity, repurposing drugs approved for other indications, finding drugs targeted to specific genetic and biochemical defects that underlie focal epilepsy syndromes, development of viral vectors for specific gene therapy, creation of devices and methods for suppression of seizures by electrostimulation and development of methods to increase safety of epilepsy surgery. Improvement of efficacy and safety of current therapies is necessary, as well as developing targeted treatment of genetic epilepsy syndromes that will not only suppress seizures, but stop further epileptogenesis.


Assuntos
Epilepsias Parciais , Epilepsia , Anticonvulsivantes/uso terapêutico , Epilepsias Parciais/tratamento farmacológico , Epilepsias Parciais/genética , Epilepsia/tratamento farmacológico , Humanos
9.
Phys Chem Chem Phys ; 23(17): 10440-10447, 2021 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-33890602

RESUMO

Experimental evidence has demonstrated that the presence of water in non-aqueous electrolytes significantly affects Li-O2 electrochemistry. Understanding the reaction mechanism for Li2O2 formation in the presence of water impurities is important to understand Li-O2 battery performance. A recent experiment has found that very small amounts of water (as low as 40 ppm) can significantly affect the product formation in Li-O2 batteries as opposed to essentially no water (1 ppm). Although experimental as well as theoretical work has proposed mechanisms of Li2O2 formation in the presence of much larger amounts of water, none of the mechanisms provide an explanation for the observations for very small amounts of water. In this work, density functional theory (DFT) was utilized to obtain a mechanistic understanding of the Li-O2 discharge chemistry in a dimethoxyethane (DME) electrolyte containing an isolated water and no water. The reaction pathways for Li2O2 formation from LiO2 on a model system were carefully evaluated with different level of theories, i.e. PBE (PW), B3LYP/6-31G(2df,p), B3LYP/6-311++G(2df,p) and G4MP2. The results indicate that the LiO2 disproportionation reaction to Li2O2 can be promoted by the water in DME electrolyte, which explains why there is a significant difference compared to when no water is present in the experimentally observed discharge product distributions. Ab initio molecular dynamics calculations were also used to investigate the disproportionation of LiO2 dimer in explicit DME. This work adds to the fundamental understanding of the discharge chemistry of a Li-O2 battery.

10.
J Am Chem Soc ; 143(7): 2741-2750, 2021 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-33399469

RESUMO

Perovskite oxides are an important class of oxygen evolution reaction (OER) catalysts in alkaline media, despite the elusive nature of their active sites. Here, we demonstrate that the origin of the OER activity in a La1-xSrxCoO3 model perovskite arises from a thin surface layer of Co hydr(oxy)oxide (CoOxHy) that interacts with trace-level Fe species present in the electrolyte, creating dynamically stable active sites. Generation of the hydr(oxy)oxide layer is a consequence of a surface evolution process driven by the A-site dissolution and O-vacancy creation. In turn, this imparts a 10-fold improvement in stability against Co dissolution and a 3-fold increase in the activity-stability factor for CoOxHy/LSCO when compared to nanoscale Co-hydr(oxy)oxides clusters. Our results suggest new design rules for active and stable perovskite oxide-based OER materials.

11.
ACS Appl Mater Interfaces ; 13(2): 3369-3376, 2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-33404211

RESUMO

The feasible commercialization of alkaline, phosphoric acid and polymer electrolyte membrane fuel cells depends on the development of oxygen reduction reaction (ORR) electrocatalysts with improved activity, stability, and selectivity. The rational design of surfaces to ensure these improved ORR catalytic requirements relies on the so-called "descriptors" (e.g., the role of covalent and noncovalent interactions on platinum surface active sites for ORR). Here, we demonstrate that through the molecular adsorption of melamine onto the Pt(111) surface [Pt(111)-Mad], the activity can be improved by a factor of 20 compared to bare Pt(111) for the ORR in a strongly adsorbing sulfuric acid solution. The Mad moieties act as "surface-blocking bodies," selectively hindering the adsorption of (bi)sulfate anions (well-known poisoning spectator of the Pt(111) active sites) while the ORR is unhindered. This modified surface is further demonstrated to exhibit improved chemical stability relative to Pt(111) patterned with cyanide species (CNad), previously shown by our group to have a similar ORR activity increase compared to bare Pt(111) in a sulfuric acid electrolyte, with Pt(111)-Mad retaining a greater than ninefold higher ORR activity relative to bare Pt(111) after extensive potential cycling as compared to a greater than threefold higher activity retained on a CNad-covered Pt(111) surface. We suggest that the higher stability of the Pt(111)-Mad interface stems from melamine's ability to form intermolecular hydrogen bonds, which effectively turns the melamine molecules into larger macromolecular entities with multiple anchoring sites and thus more difficult to remove.

12.
ACS Appl Mater Interfaces ; 12(32): 36137-36147, 2020 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-32667178

RESUMO

Developing next-generation battery chemistries that move beyond traditional Li-ion systems is critical to enabling transformative advances in electrified transportation and grid-level energy storage. In this work, we provide the first evidence for common descriptors for improved reversibility of metal plating/stripping in nonaqueous electrolytes for multivalent ion batteries. Focusing first on the specific role of chloride (Cl-) in promoting electrochemical reversibility in multivalent systems, rotating disk (RDE) and ring-disk electrode (RRDE) investigations were performed utilizing a variety of divalent cations (Mg2+, Zn2+, and Cu2+) and the bis-(trifluoromethane sulfonyl) imide (TFSI-) anion. By introducing varying concentrations of Cl-, a cooperative effect is observed between TFSI- and Cl- that yields the more reversible behavior of mixed electrolytes relative to electrolytes containing only TFSI-. This effect is shown to be general for Mg, Zn, and Cu electrodeposition, and mechanistic understanding of the role of Cl- in improving reversibility of TFSI-based electrolytes is obtained through the combination of R(R)DE experimental results and density functional theory (DFT) evaluation of the redox activity and thermodynamic stability of various TFSI- and Cl-based solution complexes of metal ions. The cooperative anion effect is further generalized to other mixed-anion systems, where systematic variations in anion association strength predicted from DFT (i.e., Cl- > OTf- ≈ TFSI- > BF4- > PF6-) yield corresponding trends in redox potentials and improvements of ≥200 mV in the reversibility of metal deposition/dissolution. These results identify anion association strength as a common descriptor for the reversibility of divalent metal anodes and suggest a set of general design principles for developing new electrolytes with improved activity and stability.

14.
Nat Mater ; 19(11): 1207-1214, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32690912

RESUMO

A remaining challenge for the deployment of proton-exchange membrane fuel cells is the limited durability of platinum (Pt) nanoscale materials that operate at high voltages during the cathodic oxygen reduction reaction. In this work, atomic-scale insight into well-defined single-crystalline, thin-film and nanoscale surfaces exposed Pt dissolution trends that governed the design and synthesis of durable materials. A newly defined metric, intrinsic dissolution, is essential to understanding the correlation between the measured Pt loss, surface structure, size and ratio of Pt nanoparticles in a carbon (C) support. It was found that the utilization of a gold (Au) underlayer promotes ordering of Pt surface atoms towards a (111) structure, whereas Au on the surface selectively protects low-coordinated Pt sites. This mitigation strategy was applied towards 3 nm Pt3Au/C nanoparticles and resulted in the elimination of Pt dissolution in the liquid electrolyte, which included a 30-fold durability improvement versus 3 nm Pt/C over an extended potential range up to 1.2 V.

15.
Chem Sci ; 11(15): 3914-3922, 2020 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-34122861

RESUMO

By combining idealized experiments with realistic quantum mechanical simulations of an interface, we investigate electro-reduction reactions of HF, water and methanesulfonic acid (MSA) on the single crystal (111) facets of Au, Pt, Ir and Cu in organic aprotic electrolytes, 1 M LiPF6 in EC/EMC 3:7W (LP57), the aprotic electrolyte commonly used in Li-ion batteries, 1 M LiClO4 in EC/EMC 3:7W and 0.2 M TBAPF6 in 3 : 7 EC/EMC. In our previous work, we have established that LiF formation, accompanied by H2 evolution, is caused by a reduction of HF impurities and requires the presence of Li at the interface, which catalyzes the HF dissociation. In the present paper, we find that the measured potential of the electrochemical response for these reduction reactions correlates with the work function of the electrode surfaces and that the work function determines the potential for Li+ adsorption. The reaction path is investigated further by electrochemical simulations suggesting that the overpotential of the reaction is related to stabilizing the active structure of the interface having adsorbed Li+. Li+ is needed to facilitate the dissociation of HF which is the source of protons. Further experiments on other proton sources, water and methanesulfonic acid, show that if the hydrogen evolution involves negatively charged intermediates, F- or HO-, a cation at the interface can stabilize them and facilitate the reaction kinetics. When the proton source is already significantly dissociated (in the case of a strong acid), there is no negatively charged intermediate and thus the hydrogen evolution can proceed at much lower overpotentials. This reveals a situation where the overpotential for electrocatalysis is related to stabilizing the active structure of the interface, facilitating the reaction rather than providing the reaction energy.

16.
ACS Appl Mater Interfaces ; 11(37): 34517-34525, 2019 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-31430112

RESUMO

Engineered solid-liquid interfaces will play an important role in the development of future energy storage and conversion (ESC) devices. In the present study, defective graphene oxide (GO) and reduced graphene oxide (rGO) structures were used as engineered interfaces to tune the selectivity and activity of Pt disk electrodes. GO was deposited on Pt electrodes via the Langmuir-Blodgett technique, which provided compact and uniform GO films, and these films were subsequently converted to rGO by thermal reduction. Electrochemical measurements revealed that both GO and rGO interfaces on Pt electrodes exhibit selectivity toward the oxygen reduction reaction (ORR), but they do not have an impact on the activity of the hydrogen oxidation reaction in acidic environments. Scanning transmission electron microscopy at atomic resolution, along with Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM), revealed possible diffusion sites for H2 and O2 gas molecules and functional groups relevant to the selectivity and activity of these surfaces. Based on these insights, rGO interfaces are further demonstrated to exhibit enhanced activity for the ORR in nonaqueous environments and demonstrate the power of our ex situ engineering approach for the development of next-generation ESC devices.

17.
Traffic Inj Prev ; 20(5): 467-471, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31157552

RESUMO

Objective: The purpose of this study is to provide an overview of the prevalence of driving under the influence of alcohol (DUI) according to day of the week, specific roads (urban/rural), daytime or nighttime, and vehicle category. In addition, this study examines how the prohibition of selling alcoholic drinks in shops and supermarkets (not in restaurants) after 10 p.m. has affected the prevalence of DUI. Method: Breath alcohol concentration (BrAC) was collected from all drivers through police checkpoints at 54 locations in Serbia. In this study, 17,945 drivers were tested in urban areas and 19,507 in rural areas. The relationship between DUI during the prohibition on alcohol sales in Belgrade and other large cities in Serbia was determined using logistic regression. Results: On average, every 100th driver in traffic in Serbia was DUI (0.99%). This study shows that the 0 blood alcohol concentration (BAC) limit for motorcyclists does not have an influence on DUI. Moreover, motorcyclists represent the category with the highest share of DUI, with a statistically significantly larger difference compared to drivers of other vehicle categories. These results may be a consequence of the fact that a large number of drivers drive both motorcycles and other vehicle categories (cars or mopeds), so the different BAC limits for nonprofessional drivers may create confusion about the legal BAC limit. Conclusions: This study suggests that the required legal BAC limit for nonprofessional drivers should be the same. The prohibition of selling alcoholic drinks in Belgrade after 10 p.m. does not decrease the prevalence of DUI.


Assuntos
Bebidas Alcoólicas/legislação & jurisprudência , Comércio/legislação & jurisprudência , Dirigir sob a Influência/estatística & dados numéricos , Concentração Alcoólica no Sangue , Humanos , Sérvia/epidemiologia
18.
J Phys Chem Lett ; 9(17): 4935-4940, 2018 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-30058338

RESUMO

The future of high-voltage rechargeable batteries is closely tied to the fundamental understanding of the processes that lead to the potential-dependent degradation of electrode materials and organic electrolytes. To date, however, there have been no methods able to provide quantitative, in situ and in real time information about the electrode dissolution kinetics and concomitant electrolyte decomposition during charge/discharge. We describe the development of such a method, which is of both fundamental and technological significance. Our novel approach enables simultaneous and independent measurements of transition-metal cation dissolution rates from different oxide hosts (Co3+/4+ or Cr3+/4+), deintercalation kinetics of working cations (Mg2+), and the relative rate of electrolyte decomposition.

19.
ACS Appl Mater Interfaces ; 10(20): 17471-17479, 2018 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-29708721

RESUMO

Understanding ionic transport across interfaces between dissimilar materials and the intrinsic chemical stability of such interfaces is a fundamental challenge spanning many disciplines and is of particular importance for designing conductive and stable solid electrolytes for solid-state Li-ion batteries. In this work, we establish a surface science-based approach for assessing the intrinsic stability of oxide materials in contact with Li metal. Through a combination of experimental and computational insights, using Nb-doped SrTiO3 (Nb/STO) single crystals as a model system, we were able to understand the impact of crystallographic orientation and surface morphology on the extent of the chemical reactions that take place between surface Nb, Ti, and Sr upon reaction with Li. By expanding our approach to investigate the intrinsic stability of the technologically relevant, polycrystalline Nb-doped lithium lanthanum zirconium oxide (Li6.5La3Zr1.5Nb0.5O12) system, we found that this material reacts with Li metal through the reduction of Nb, similar to that observed for Nb/STO. These results clearly demonstrate the feasibility of our approach to assess the intrinsic (in)stability of oxide materials for solid-state batteries and point to new strategies for understanding the performance of such systems.

20.
Nat Commun ; 8(1): 1449, 2017 11 13.
Artigo em Inglês | MEDLINE | ID: mdl-29129907

RESUMO

The selection of oxide materials for catalyzing the oxygen evolution reaction in acid-based electrolyzers must be guided by the proper balance between activity, stability and conductivity-a challenging mission of great importance for delivering affordable and environmentally friendly hydrogen. Here we report that the highly conductive nanoporous architecture of an iridium oxide shell on a metallic iridium core, formed through the fast dealloying of osmium from an Ir25Os75 alloy, exhibits an exceptional balance between oxygen evolution activity and stability as quantified by the activity-stability factor. On the basis of this metric, the nanoporous Ir/IrO2 morphology of dealloyed Ir25Os75 shows a factor of ~30 improvement in activity-stability factor relative to conventional iridium-based oxide materials, and an ~8 times improvement over dealloyed Ir25Os75 nanoparticles due to optimized stability and conductivity, respectively. We propose that the activity-stability factor is a key "metric" for determining the technological relevance of oxide-based anodic water electrolyzer catalysts.

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