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1.
Rev Esc Enferm USP ; 58: e20230347, 2024.
Artigo em Inglês, Português | MEDLINE | ID: mdl-38949510

RESUMO

OBJECTIVE: To report the experience of implementing the São Paulo Nursing Courses Consortium for the Progress Test. METHOD: This is an experience report of the consortium's work in Progress Test preparation and application for Public Schools of Nursing in São Paulo in 2019, 2021 and 2022, with a descriptive analysis of the work process and the results obtained. RESULTS: The consortium's activities are structured into the following stages: planning; theme review; distributing and requesting questions; professor training; question elaboration; question reception; question selection; question validation; student registration; test application; analysis and dissemination of results. A total of 57.3% of enrolled students participated. There was a predominance of questions of medium difficulty and a gradual progression in the level of discrimination of the questions, with, in 2022, 82.5% being considered adequate. FINAL CONSIDERATIONS: The consortium has allowed the test to be applied interinstitutionally, with greater scope, accuracy, and quality of questions. Through this experience, it is expected to encourage progress testing in undergraduate nursing courses in other contexts.


Assuntos
Avaliação Educacional , Estudantes de Enfermagem , Brasil , Humanos , Avaliação Educacional/métodos , Bacharelado em Enfermagem/métodos , Educação em Enfermagem/métodos , Escolas de Enfermagem/organização & administração
2.
ACS Catal ; 11(16): 10604-10613, 2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34484854

RESUMO

Effective catalysts for the direct conversion of methane to methanol and for methane's dry reforming to syngas are Holy Grails of catalysis research toward clean energy technologies. It has recently been discovered that Ni at low loadings on CeO2(111) is very active for both of these reactions. Revealing the nature of the active sites in such systems is paramount to a rational design of improved catalysts. Here, we correlate experimental measurements on the CeO2(111) surface to show that the most active sites are cationic Ni atoms in clusters at step edges, with a small size wherein they have the highest Ni chemical potential. We clarify the reasons for this observation using density functional theory calculations. Focusing on the activation barrier for C-H bond cleavage during the dissociative adsorption of CH4 as an example, we show that the size and morphology of the supported Ni nanoparticles together with strong Ni-support bonding and charge transfer at the step edge are key to the high catalytic activity. We anticipate that this knowledge will inspire the development of more efficient catalysts for these reactions.

3.
ACS Catal ; 11(13): 8327-8337, 2021 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-34306812

RESUMO

Methane steam reforming (MSR) plays a key role in the production of syngas and hydrogen from natural gas. The increasing interest in the use of hydrogen for fuel cell applications demands development of catalysts with high activity at reduced operating temperatures. Ni-based catalysts are promising systems because of their high activity and low cost, but coke formation generally poses a severe problem. Studies of ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) indicate that CH4/H2O gas mixtures react with Ni/CeO2(111) surfaces to form OH, CH x , and CH x O at 300 K. All of these species are easy to form and desorb at temperatures below 700 K when the rate of the MSR process is accelerated. Density functional theory (DFT) modeling of the reaction over ceria-supported small Ni nanoparticles predicts relatively low activation barriers between 0.3 and 0.7 eV for complete dehydrogenation of methane to carbon and the barrierless activation of water at interfacial Ni sites. Hydroxyls resulting from water activation allow for CO formation via a COH intermediate with a barrier of about 0.9 eV, which is much lower than that through a pathway involving lattice oxygen from ceria. Neither methane nor water activation is a rate-determining step, and the OH-assisted CO formation through the COH intermediate constitutes a low-barrier pathway that prevents carbon accumulation. The interactions between Ni and the ceria support and the low metal loading are crucial for the reaction to proceed in a coke-free and efficient way. These results pave the way for further advances in the design of stable and highly active Ni-based catalysts for hydrogen production.

4.
Phys Chem Chem Phys ; 23(6): 3826-3836, 2021 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-33533765

RESUMO

The water-gas shift (WGS) reaction is a key step in hydrogen production, particularly to meet the high-purity H2 requirement of PEM fuel cells. The catalysts currently employed in large-scale WGS plants require a two-step process to overcome thermodynamic and kinetic limitations. Ni-Cu/CeO2 solids are promising catalysts for the one-step process required for small-scale applications, as the addition of Cu hinders undesired methanation reactions occurring on Ni/CeO2. In this work, we performed calculations on Ni4-xCux/CeO2(111) systems to evaluate the influence of cluster conformation on the selectivity towards water-gas shift. The structure and miscibility of CeO2-supported Ni4-xCux clusters were investigated and compared with those of gas-phase clusters to understand the effect of metal-support interactions. The adsorption of CO onto apical Ni and Cu atoms of Ni4-xCux/CeO2(111) systems was studied, and changes in the C-O bond strength were confirmed at the electronic level by investigating shifts in the 3σ and 1π orbitals. The selectivity towards WGS was evaluated using Brønsted-Evans-Polanyi relations for the C-O activation energy. Overall, a strengthening of the C-O bond and an increase in CO dissociation energy were verified on Cu-containing clusters, explaining the improvement in selectivity of Ni4-xCux/CeO2(111) systems.

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