Video Experimental Relacionado

Updated: Feb 22, 2026

Developing Photosensitizer-Cobaloxime Hybrids for Solar-Driven H2 Production in Aqueous Aerobic Conditions

Developing Photosensitizer-Cobaloxime Hybrids for Solar-Driven H2 Production in Aqueous Aerobic Conditions

Published on: October 5, 2019

Dependencia de la temperatura de la reducción catalítica de dos contra cuatro electrones del oxígeno por un complejo

Inés Monte-Pérez¹, Subrata Kundu¹, Anirban Chandra¹

¹Humboldt-Universität zu Berlin , Institut für Chemie, Brook-Taylor-Straße 2, D-12489 Berlin, Germany.

Journal of the American Chemical Society

|September 28, 2017

Resumen

Un nuevo complejo de cobalto hexanuclear cataliza la reducción de oxígeno, produciendo selectivamente agua o peróxido de hidrógeno según la temperatura. Este descubrimiento ofrece principios para diseñar catalizadores eficientes de pila de combustible.

Área de la Ciencia:

Química de coordinación
Catálisis
Ciencias de los materiales

Sus antecedentes:

El desarrollo de catalizadores eficientes para la reducción de dioxígeno es crucial para aplicaciones energéticas como las pilas de combustible.
El control de la selectividad de la reducción de dioxígeno (a agua o peróxido de hidrógeno) sigue siendo un desafío importante.

Objetivo del estudio:

Para sintetizar y caracterizar un nuevo complejo de cobalto hexanuclear apoyado en un núcleo de estanxane.
Investigar la actividad catalítica y la selectividad del complejo en la reducción de dioxígeno.
Elucidar el mecanismo subyacente a la selectividad dependiente de la temperatura del proceso catalítico.

Principales métodos:

Síntesis y caracterización del complejo de cobalto hexanuclear mediante diversas técnicas espectroscópicas (NMR, MCD, EPR, SQUID, UV-vis, XAS).
Estudios cinéticos de la reacción de reducción del dioxígeno y sus productos intermedios a diferentes temperaturas (-50 °C y 25 °C).
Cálculos teóricos avanzados para determinar la estructura geométrica y electrónica y los mecanismos de reacción.

Principales resultados:

Se sintetizó con éxito un complejo de cobalto hexanuclear (1) con un sistema de ligando no hemo en un núcleo de estanxane.
El complejo 1 muestra una selectividad ajustable para la reducción de dioxígeno: 4e-/4H+ a agua a -50 °C y 2e-/2H+ a peróxido de hidrógeno a 25 °C.
La restricción del núcleo de estanxane en la unión de O2 influye en las vías de reacción, favoreciendo la transferencia de protones a temperaturas más altas y la escisión de enlaces O-O a través de PCET a temperaturas más bajas.

Conclusiones:

El estudio proporciona profundos conocimientos mecánicos sobre la reducción de dioxígeno, destacando el papel de la temperatura y la estructura del catalizador.
Los hallazgos ofrecen una base para el diseño de catalizadores avanzados con selectividad controlable para aplicaciones de celdas de combustible.
El cambio dependiente de la temperatura en la selectividad demuestra una nueva estrategia para ajustar los resultados catalíticos.

Más Videos Relacionados

Multiscale Sampling of a Heterogeneous Water/Metal Catalyst Interface using Density Functional Theory and Force-Field Molecular Dynamics

Multiscale Sampling of a Heterogeneous Water/Metal Catalyst Interface using Density Functional Theory and Force-Field Molecular Dynamics

Published on: April 12, 2019

Synthesis and Performance Characterizations of Transition Metal Single Atom Catalyst for Electrochemical CO2 Reduction

Synthesis and Performance Characterizations of Transition Metal Single Atom Catalyst for Electrochemical CO2 Reduction

Published on: April 10, 2018

Videos de Conceptos Relacionados

Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide

Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide

Alkenes are converted to 1,2-diols or glycols through a process called dihydroxylation. It involves the addition of two hydroxyl groups across the double bond with two different stereochemical approaches, namely anti and syn. Dihydroxylation using osmium tetroxide progresses with syn stereochemistry.

Reduction of Alkenes: Catalytic Hydrogenation

Reduction of Alkenes: Catalytic Hydrogenation

Alkenes undergo reduction by the addition of molecular hydrogen to give alkanes. Because the process generally occurs in the presence of a transition-metal catalyst, the reaction is called catalytic hydrogenation.
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the...

Reduction of Benzene to Cyclohexane: Catalytic Hydrogenation

Reduction of Benzene to Cyclohexane: Catalytic Hydrogenation

Unlike the easy catalytic hydrogenation of an alkene double bond, hydrogenation of a benzene double bond under similar reaction conditions does not take place easily. For example, in the reduction of stilbene, the benzene ring remains unaffected while the alkene bond gets reduced. Hydrogenation of an alkene double bond is exothermic and a favorable process. In contrast, to hydrogenate the first unsaturated bond of benzene, an energy input is needed; that is, the process is endothermic. This is...

Oxidation of Alkenes: Syn Dihydroxylation with Potassium Permanganate

Oxidation of Alkenes: Syn Dihydroxylation with Potassium Permanganate

Alkenes can be dihydroxylated using potassium permanganate. The method encompasses the reaction of an alkene with a cold, dilute solution of potassium permanganate under basic conditions to form a cis-diol along with a brown precipitate of manganese dioxide.

Redox Reactions

Redox Reactions

Oxidation-reduction or redox reactions involve the transfer of electrons from one molecule or atom to another. When an atom gains an electron, another atom must lose an electron, meaning oxidation and reduction must occur together. Since the redox occurs in pairs, the atom that gets oxidized is also called the reducing agent or reductant, and the atom that is reduced is also called the oxidizing agent or oxidant. A straightforward way to remember the definitions of oxidation and reduction is...

Redox Reactions

Redox Reactions

Redox reactions are vital biochemical processes that underpin energy metabolism in cells. These reactions involve the transfer of electrons between molecules, occurring in tandem as oxidation and reduction. Oxidation refers to the loss of electrons, while reduction denotes their gain. This coupling ensures the seamless flow of electrons through metabolic pathways. For example, in bacterial metabolism, glucose undergoes oxidation to carbon dioxide, while oxygen is simultaneously reduced to...