Topic
Overpotential
About: Overpotential is a research topic. Over the lifetime, 16474 publications have been published within this topic receiving 616632 citations.
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TL;DR: Polarization and electrical conductivity measurements were made at 800°C in open air using the perovskite-type oxides La 1− x Sr x MO 3 (M Cr, Mn, Fe, Co) sputtered on ytteia stabilized zirconia electrolyte.
498 citations
TL;DR: In this article, the authors provide an overview of some important investigations performed on the development of efficient electrocatalysts in the presence of alkaline solutions, which must encounter different characteristics such as low overpotential for hydrogen evolution reaction (HER), good catalytic activity, high stability and low cost.
495 citations
TL;DR: A novel and effective approach is developed for synthesizing ultrafine Co nanoparticles encapsulated in nitrogen-doped carbon nanotubes grafted onto both sides of reduced graphene oxide (rGO) by direct annealing of GO-wrapped core-shell bimetallic zeolite imidazolate frameworks, which may open a new avenue toward the development of nonprecious high-performance HER catalysts.
Abstract: The rational design of an efficient and inexpensive electrocatalyst based on earth-abundant 3d transition metals (TMs) for the hydrogen evolution reaction still remains a significant challenge in the renewable energy area. Herein, a novel and effective approach is developed for synthesizing ultrafine Co nanoparticles encapsulated in nitrogen-doped carbon nanotubes (N-CNTs) grafted onto both sides of reduced graphene oxide (rGO) (Co@N-CNTs@rGO) by direct annealing of GO-wrapped core-shell bimetallic zeolite imidazolate frameworks. Benefiting from the uniform distribution of Co nanoparticles, the in-situ-formed highly graphitic N-CNTs@rGO, the large surface area, and the abundant porosity, the as-fabricated Co@N-CNTs@rGO composites exhibit excellent electrocatalytic hydrogen evolution reaction (HER) activity. As demonstrated in electrochemical measurements, the composites can achieve 10 mA cm-2 at low overpotential with only 108 and 87 mV in 1 m KOH and 0.5 m H2 SO4 , respectively, much better than most of the reported Co-based electrocatalysts over a wide pH range. More importantly, the synthetic strategy is versatile and can be extended to prepare other binary or even ternary TMs@N-CNTs@rGO (e.g., Co-Fe@N-CNTs@rGO and Co-Ni-Cu@N-CNTs@rGO). The strategy developed here may open a new avenue toward the development of nonprecious high-performance HER catalysts.
494 citations
TL;DR: A new way for designing oxygen vacancies dominated interface nanowires as highly efficient multifunctional electrocatalysts for electrochemical reactions and renewable energy devices is opened.
Abstract: The development of highly active and stable oxygen evolution reaction (OER) electrocatalysts is crucial for improving the efficiency of water splitting and metal-air battery devices. Herein, an efficient strategy is demonstrated for making the oxygen vacancies dominated cobalt-nickel sulfide interface porous nanowires (NiS2 /CoS2 -O NWs) for boosting OER catalysis through in situ electrochemical reaction of NiS2 /CoS2 interface NWs. Because of the abundant oxygen vacancies and interface porous nanowires structure, they can catalyze the OER efficiently with a low overpotential of 235 mV at j = 10 mA cm-2 and remarkable long-term stability in 1.0 m KOH. The home-made rechargeable portable Zn-air batteries by using NiS2 /CoS2 -O NWs as the air-cathode display a very high open-circuit voltage of 1.49 V, which can maintain for more than 30 h. Most importantly, a highly efficient self-driven water splitting device is designed with NiS2 /CoS2 -O NWs as both anode and cathode, powered by two-series-connected NiS2 /CoS2 -O NWs-based portable Zn-air batteries. The present work opens a new way for designing oxygen vacancies dominated interface nanowires as highly efficient multifunctional electrocatalysts for electrochemical reactions and renewable energy devices.
494 citations
TL;DR: The facile preparation of this Co-S film, along with its low overpotential, high activity, and long-term aqueous stability, offer promising features for potential use in solar energy applications.
Abstract: A cobalt-sulfide (Co-S) film prepared via electrochemical deposition on conductive substrates is shown to behave as an efficient and robust catalyst for electrochemical and photoelectrochemical hydrogen generation from neutral pH water. Electrochemical experiments demonstrate that the film exhibits a low catalytic onset overpotential (η) of 43 mV, a Tafel slope of 93 mV/dec, and near 100% Faradaic efficiency in pH 7 phosphate buffer. Catalytic current densities can approach 50 mA/cm(2) and activity is maintained for at least 40 h. The catalyst can also be electrochemically coated on silicon, rendering a water-compatible photoelectrochemical system for hydrogen production under simulated 1 sun illumination. The facile preparation of this Co-S film, along with its low overpotential, high activity, and long-term aqueous stability, offer promising features for potential use in solar energy applications.
492 citations