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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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Journal ArticleDOI
Abstract: Electrochemical water splitting in alkaline solution plays a growing role in alternative energy devices due to the need for clean and sustainable energy. However, catalysts that are active for both hydrogen evolution and oxygen evolution reactions are rare. Herein, we demonstrate that cobalt phosphide (CoP), which was synthesized via the hydrothermal route and has been shown to have hydrogen evolution activity, is highly active for oxygen evolution. A current density of 10 mA cm–2 was generated at an overpotential of only 320 mV in 1 M KOH for a CoP nanorod-based electrode (CoP NR/C), which was competitive with commercial IrO2. The Tafel slope for CoP NR/C was only 71 mV dec–1, and the catalyst maintained high stability during a 12 h test. This high activity was attributed to the formation of a thin layer of ultrafine crystalline cobalt oxide on the CoP surface.

414 citations

Journal ArticleDOI
TL;DR: In this article, a three-dimensional Ni(OH) 2 /MoS 2 hybrid catalyst with synergistic effect has been synthesized by a facile approach for efficient alkaline hydrogen evolution reaction.

412 citations

Journal ArticleDOI
Mengzhou Yu1, Si Zhou1, Zhiyu Wang1, Jijun Zhao1, Jieshan Qiu1 
TL;DR: In this paper, a new type of non-precious metal electrocatalyst for OER by synergistically coupling layered double hydroxides (LDH) with two-dimensional (2D) MXene with high conductivity and active surface was reported.

412 citations

Journal ArticleDOI
TL;DR: A flexible cloth-like electrode, which can efficiently split water to produce H2 at neutral pH, is successfully demonstrated and has excellent electrocatalytic stability over an extended period, much better than those of MoS2/C and Pt plate electrodes.
Abstract: A unique functional electrode made of hierarchal Ni-Mo-S nanosheets with abundant exposed edges anchored on conductive and flexible carbon fiber cloth, referred to as Ni-Mo-S/C, has been developed through a facile biomolecule-assisted hydrothermal method. The incorporation of Ni atoms in Mo-S plays a crucial role in tuning its intrinsic catalytic property by creating substantial defect sites as well as modifying the morphology of Ni-Mo-S network at atomic scale, resulting in an impressive enhancement in the catalytic activity. The Ni-Mo-S/C electrode exhibits a large cathodic current and a low onset potential for hydrogen evolution reaction in neutral electrolyte (pH ~7), for example, current density of 10 mA/cm2 at a very small overpotential of 200 mV. Furthermore, the Ni-Mo-S/C electrode has excellent electrocatalytic stability over an extended period, much better than those of MoS2/C and Pt plate electrodes. Scanning and transmission electron microscopy, Raman spectroscopy, x-ray diffraction, x-ray photoelectron spectroscopy, and x-ray absorption spectroscopy were used to understand the formation process and electrocatalytic properties of Ni-Mo-S/C. The intuitive comparison test was designed to reveal the superior gas-evolving profile of Ni-Mo-S/C over that of MoS2/C, and a laboratory-scale hydrogen generator was further assembled to demonstrate its potential application in practical appliances.

412 citations

Journal ArticleDOI
TL;DR: It is disclosed that the isolated single atom ruthenium was kept under the oxidation states of 4+ even at high overpotential due to synergetic electron coupling, which endow exceptional electrocatalytic activity and stability simultaneously.
Abstract: Single atom catalyst, which contains isolated metal atoms singly dispersed on supports, has great potential for achieving high activity and selectivity in hetero-catalysis and electrocatalysis. However, the activity and stability of single atoms and their interaction with support still remains a mystery. Here we show a stable single atomic ruthenium catalyst anchoring on the surface of cobalt iron layered double hydroxides, which possesses a strong electronic coupling between ruthenium and layered double hydroxides. With 0.45 wt.% ruthenium loading, the catalyst exhibits outstanding activity with overpotential 198 mV at the current density of 10 mA cm−2 and a small Tafel slope of 39 mV dec−1 for oxygen evolution reaction. By using operando X-ray absorption spectroscopy, it is disclosed that the isolated single atom ruthenium was kept under the oxidation states of 4+ even at high overpotential due to synergetic electron coupling, which endow exceptional electrocatalytic activity and stability simultaneously. While water splitting offers a carbon-neutral means to store energy, water oxidation is sluggish and corrosive over earth-abundant electrocatalysts. Here, authors show single ruthenium atoms over cobalt-iron layered double hydroxides to be effective and stable oxygen evolution electrocatalysts.

411 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20232,316
20224,268
20212,838
20202,411
20192,174
20181,740