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1.
ACS Catal ; 14(11): 8814-8822, 2024 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-38868103

RESUMEN

The electrode-electrolyte interface, and in particular the nature of the cation, has considerable effects on the activity and product selectivity of the electrochemical reduction of CO2. Therefore, to improve the electrocatalysis of this challenging reaction, it is paramount to ascertain whether cation effects on adsorbed intermediates are systematic. Here, DFT calculations are used to show that the effects of K+, Na+, and Mg2+, on single carbon CO2 reduction intermediates can either be stabilizing or destabilizing depending on the metal and the adsorbate. Because systematic trends are observed, cation effects can be accurately predicted in simple terms for a wide variety of metals, cations and adsorbed species. These results are then applied to the reduction of CO2 to CO on four different catalytic surfaces (Au, Ag, Cu, Pd) and activation of weak-binding metals is consistently observed by virtue of the stabilization of the key intermediate *COOH.

2.
Molecules ; 28(15)2023 Jul 25.
Artículo en Inglés | MEDLINE | ID: mdl-37570611

RESUMEN

The current race for space exploration has hastened the development of electrochemical technologies for the in-situ utilisation of planetary resources for the synthesis of vital chemicals such as O2 and fuels. Understanding the physicochemical properties, such as the density and kinematic viscosity, of aqueous solutions is essential for the design of electrochemical devices for the electrolysis of water and CO2, particularly at low temperatures. The density and kinematic viscosity of highly concentrated Mg(ClO4)2 and KOH solutions have been determined, both at low temperatures and in the presence of CO2 gas. It was found that, for all of the solutions, independent of the concentration or nature of the electrolyte, as the temperature was decreased to 255 K, the density and the viscosity of the solutions increased. Upon saturation with CO2, no significant change to the density and viscosity of Mg(ClO4)2, at all of the temperatures measured, was observed. Conversely, the CO2 saturated solutions of KOH showed significant changes in density and viscosity at all temperatures, likely due to the formation of carbonates. The effects of these changes on the diffusion coefficient for dissolved CO2 is also discussed.

3.
ACS Appl Mater Interfaces ; 14(2): 2742-2753, 2022 Jan 19.
Artículo en Inglés | MEDLINE | ID: mdl-34982523

RESUMEN

The electrochemical conversion of carbon dioxide (CO2) to useful chemical fuels is a promising route toward the achievement of carbon neutral and carbon negative energy technologies. Copper (Cu)- and Cu oxide-derived surfaces are known to electrochemically convert CO2 to high-value and energy-dense products. However, the nature and stability of oxidized Cu species under reaction conditions are the subject of much debate in the literature. Herein, we present the synthesis and characterization of copper-titanate nanocatalysts, with discrete Cu-O coordination environments, for the electrochemical CO2 reduction reaction (CO2RR). We employ real-time in situ X-ray absorption spectroscopy (XAS) to monitor Cu species under neutral-pH CO2RR conditions. Combination of voltammetry and on-line electrochemical mass spectrometry with XAS results demonstrates that the titanate motif promotes the retention of oxidized Cu species under reducing conditions for extended periods, without itself possessing any CO2RR activity. Additionally, we demonstrate that the specific nature of the Cu-O environment and the size of the catalyst dictate the long-term stability of the oxidized Cu species and, subsequently, the product selectivity.

4.
Am J Primatol ; 78(6): 659-68, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-26815856

RESUMEN

Evidence for paternal kin recognition and paternally biased behaviors is mixed among primates. We investigate whether infant handling behaviors exhibit paternal kin biases in wild white-faced capuchins monkeys (Cebus capucinus) by comparing interactions between infants and genetic sires, potential sires, siblings (full sibling, maternal, and paternal half-siblings) and unrelated handlers. We used a linear mixed model approach to analyze data collected on 21 focal infants from six groups in Sector Santa Rosa, Costa Rica. Our analyses suggest that the best predictor of adult and subadult male interactions with an infant is the male's dominance status, not his paternity status. We found that maternal siblings but not paternal siblings handled infants more than did unrelated individuals. We conclude that maternal but not paternal kinship influence patterns of infant handling in white-faced capuchins, regardless of whether or not they can recognize paternal kin. Am. J. Primatol. 78:659-668, 2016. © 2016 Wiley Periodicals, Inc.


Asunto(s)
Conducta Animal , Cebus , Animales , Costa Rica , Femenino , Masculino , Filipinas , Reconocimiento en Psicología
5.
Int J Psychophysiol ; 73(3): 246-56, 2009 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-19374924

RESUMEN

The central aim of this study was to evaluate the value of reaction time (RT) measures and event-related potentials (ERPs) for the assessment of simulated memory impairment. In two identical experiments (N=24), healthy volunteers carried out an adapted version of the Amsterdam Short-Term Memory (ASTM) test. In half of the cases participants were instructed to perform to their best of abilities (control condition) while in the other half participants were asked to feign a believable memory deficit (simulation condition). Compared to controls, simulating participants were found to produce longer and more variable RTs. In addition, they took longer to respond to new words than to old words, while control participants showed the opposite pattern. Both early (300-500 ms) and late (500-800 ms) ERP old/new effects were similar in magnitude and scalp distribution for both groups of participants, regardless of the fact that simulating participants had significantly lower recognition accuracy than controls. The ERP old/new effect was assumed to reflect unaffected retrieval mechanisms and thus the discrepancy between this measure and recognition performance was interpreted as evidence for intentional underperformance. Results are discussed in relation to clinical observations and deception detection studies. It was concluded that the combined use of RT and ERP measures could be useful to detect and evaluate simulation of memory impairment but that future studies should include patient groups to test some of our assumptions.


Asunto(s)
Potenciales Evocados/fisiología , Simulación de Enfermedad/diagnóstico , Trastornos de la Memoria/fisiopatología , Memoria a Corto Plazo/fisiología , Tiempo de Reacción/fisiología , Adolescente , Adulto , Análisis de Varianza , Distribución de Chi-Cuadrado , Electroencefalografía/métodos , Femenino , Humanos , Masculino , Simulación de Enfermedad/fisiopatología , Pruebas Neuropsicológicas , Adulto Joven
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