Oxygen Reduction by Homogeneous Molecular Catalysts and Electrocatalysts

Chemical Reviews, Год журнала: 2018, Номер 118(5), С. 2340 - 2391

Опубликована: Фев. 6, 2018

The oxygen reduction reaction (ORR) is a key component of biological processes and energy technologies. This Review provides comprehensive report soluble molecular catalysts electrocatalysts for the ORR. precise synthetic control relative ease mechanistic study homogeneous catalysts, as compared to heterogeneous materials or surface-adsorbed species, enables detailed understanding individual steps ORR catalysis. Thus, places particular emphasis on mechanism thermodynamics. First, thermochemistry factors influencing efficiency are described contextualize discussion catalytic studies that follows. Reports catalysis presented in terms their mechanism, with separate sections proceeding via initial outer- inner-sphere electron transfer O2. rates selectivities (for production H2O2 vs H2O) these provided, along suggested methods accurately comparing different metals ligand scaffolds were examined under experimental conditions.

Язык: Английский

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Electrocatalytic reduction of carbon dioxide to carbon monoxide and methane at an immobilized cobalt protoporphyrin

Nature Communications, Год журнала: 2015, Номер 6(1)

Опубликована: Сен. 1, 2015

Abstract The electrochemical conversion of carbon dioxide and water into useful products is a major challenge in facilitating closed cycle. Here we report cobalt protoporphyrin immobilized on pyrolytic graphite electrode that reduces an aqueous acidic solution at relatively low overpotential (0.5 V), with efficiency selectivity comparable to the best porphyrin-based electrocatalyst literature. While monoxide main reduction product, also observe methane as by-product. results our detailed pH-dependent studies are explained consistently by mechanism which activated through stabilization radical intermediate, acts Brønsted base. basic character this intermediate explains how circumvents concerted proton–electron transfer mechanism, contrast hydrogen evolution. Our their mechanistic interpretations suggest strategies for designing improved catalysts.

Язык: Английский

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Activation of surface oxygen sites on an iridium-based model catalyst for the oxygen evolution reaction

Nature Energy, Год журнала: 2016, Номер 2(1)

Опубликована: Дек. 19, 2016

Язык: Английский

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Engineering active sites on hierarchical transition bimetal oxides/sulfides heterostructure array enabling robust overall water splitting

Nature Communications, Год журнала: 2020, Номер 11(1)

Опубликована: Окт. 29, 2020

Rational design of the catalysts is impressive for sustainable energy conversion. However, there a grand challenge to engineer active sites at interface. Herein, hierarchical transition bimetal oxides/sulfides heterostructure arrays interacting two-dimensional MoOx/MoS2 nanosheets attached one-dimensional NiOx/Ni3S2 nanorods were fabricated by oxidation/hydrogenation-induced surface reconfiguration strategy. The NiMoOx/NiMoS array exhibits overpotentials 38 mV hydrogen evolution and 186 oxygen 10 mA cm-2, even surviving large current density 500 cm-2 with long-term stability. Due optimized adsorption energies accelerated water splitting kinetics theory calculations, assembled two-electrode cell delivers industrially relevant densities 1000 record low voltages 1.60 1.66 V excellent durability. This research provides promising avenue enhance electrocatalytic performance engineering interfacial toward large-scale splitting.

Язык: Английский

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Photon-Driven Nitrogen Fixation: Current Progress, Thermodynamic Considerations, and Future Outlook

ACS Catalysis, Год журнала: 2017, Номер 7(4), С. 2624 - 2643

Опубликована: Март 1, 2017

Over the last century, industrialization of agriculture and consumption fossil fuels have resulted in a significant imbalance redistribution nitrogen-containing resources. This has sparked an interest developing more sustainable resilient approaches for producing commodities such as fertilizers fuels. One largely neglected but emerging approach is photocatalytic nitrogen fixation. There evidence that this process occurs spontaneously terrestrial settings, it been demonstrated numerous engineered systems. Yet many questions still remain unanswered regarding rates, mechanisms, impacts photocatalytically fixed "out thin air". work reviews fascinating history reaction examines current progress toward understanding improving photofixation nitrogen. supplemented by quantitative review thermodynamic considerations limitations various mechanisms. Finally, future prospects preliminary performance targets fixation are discussed.

Язык: Английский

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