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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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TL;DR: In this paper, it was shown that the catalytic activity of polycrystalline Pt for the oxidation of ethylene to CO 2 and H 2 O can be increased by up to a factor of 50 when oxygen anions O 2− are electrochemically pumped onto the Pt catalyst surface.

193 citations

Journal ArticleDOI
Wenzhuo Wu1, Chun-Yao Niu1, Cong Wei1, Yu Jia1, Chong Li1, Qun Xu1 
TL;DR: Density functional theory calculations reveal that the zinc atoms not only lower the formation energy of S vacancies, but also help to decrease ΔGH of S-vacancy sites near the Zn atoms.
Abstract: Molybdenum disulfide (MoS2 ) has been widely studied as a potential earth-abundant electrocatalyst for the hydrogen-evolution reaction (HER). Defect engineering and heteroelemental doping are effective methods to enhance the catalytic activity in the HER, so exploring an efficient route to simultaneously achieve in-plane vacancy engineering and elemental doping of MoS2 is necessary. In this study, Zinc, a low-cost and moderately active metal, has been used to realize this strategy by generation of sulfur vacancies and zinc doping on MoS2 in one step. Density functional theory calculations reveal that the zinc atoms not only lower the formation energy of S vacancies, but also help to decrease ΔGH of S-vacancy sites near the Zn atoms. At an optimal zinc-reduced MoS2 (Zn@MoS2 ) example, the activated basal planes contribute to the HER activity with an overpotential of -194 mV at 10 mA cm-2 and a low Tafel slope of 78 mV/dec.

193 citations

Journal ArticleDOI
TL;DR: In this paper, an in-situ hybridization of Nickel Selenide (Ni3Se2) with a Nickel Foam (NF) current collector was proposed as an efficient, ultra-durable electrode for the continuous alkaline water electrolysis.
Abstract: Herein, we describe an in-situ hybridization of Nickel Selenide (Ni3Se2) with a Nickel Foam (NF) current collector as an efficient, ultra-durable electrode for the continuous alkaline water electrolysis. Earth abundant, cost effective, non-precious self-made Ni3Se2/NF electrode delivers an oxygen evolution reaction (OER) overpotential value of 315 mV at a current density of 100 mA cm−2 (versus a reversible hydrogen electrode) in aqueous electrolyte of 1 M KOH. On a static current density of 100 mA cm−2, Ni3Se2/NF electrode shows a good OER stability over 285 h with very small potential loss of 5.5% in alkaline electrolyte. Accordingly, the alkaline water electrolyzer constructed with Ni3Se2/NF (anode) and NiCo2S4/NF (cathode), it requires 1.58 V to deliver 10 mA cm−2 current density, with 500 h continuous operation in 1 M KOH. In addition, we demonstrate that the light-driven water splitting using solar panel, it can be a promising approach to facilitate true independence from electricity in H2 fuel economy. Overall, this methodology is one of the appropriate energy efficient ways to reduce the cost of water splitting devices, as it may simplify the diverse process and equipment.

193 citations

Journal ArticleDOI
TL;DR: In this article, a 3D OER electrocatalyst with high long-term electrochemical durability was proposed, which has a current density of 10mV at overpotential of only 288mV, which is 120mV less than that for MnO 2 /Ti.

192 citations

Journal ArticleDOI
TL;DR: In this paper, a two-stage encapsulation strategy was proposed to regulate the structure and performance of catalysts with thin graphene nanosheets coupled with full encapsulated ultrafine and high-loaded transition metal nanoparticles (TMs@NCX) for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER).
Abstract: Rational design of electrocatalysts to replace the noble-metal-based materials for oxygen reactions is highly desirable but challenging for rechargeable metal–air batteries. Herein, we demonstrate a unique two stage encapsulation strategy to regulate the structure and performance of catalysts featured with thin graphene nanosheets coupling with full encapsulated ultrafine and high-loaded (∼25 wt %) transition metal nanoparticles (TMs@NCX) for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). By optimizing the electronic modulation effect from suitable metal cores, the best NiFe@NCX catalyst exhibits high stability and activity with an onset potential of 1.03 V for ORR and an overpotential of only 0.23 V at 10 mA cm–2 for OER, which is superior to commercial Pt/C and IrO2 catalysts. Rechargeable Zn–air battery using NiFe@NCX catalyst exhibited an unprecedented small charge–discharge overpotential of 0.78 V at 50 mA cm–2, high reversibility, and stability, holding great promise for the pr...

192 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