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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
TL;DR: Au-Ni core-shell nanorods (NRs) and Au-Pt- Ni core-sandwich-shell NRs are synthesized and exhibit high activity for selective H2 O2 production via direct oxygen reduction through the tuning of the oxygen reduction pathway.
Abstract: Au-Ni core-shell nanorods (NRs) and Au-Pt-Ni core-sandwich-shell NRs are synthesized and exhibit high activity for selective H2 O2 production via direct oxygen reduction. The epitaxial growth with coherent lattice fringes allow for the tuning of the oxygen reduction pathway. Moreover, a selectivity of 95% and mass activity of 192.9 A g-1noble metal are achieved using Au-Pt-Ni NRs at 150 mV overpotential.

185 citations

Journal ArticleDOI
TL;DR: Wang et al. as discussed by the authors designed a facial strategy to synthesize N,P-doped defective carbon nanosheets first and then cover doped sites with well-define metal-N4 macrocyclic molecules through non-pyrolysis process.
Abstract: Experimental and computational studies show that topological defect and FeN4 site in carbon materials would deliver high performances for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Either defect or FeN4 site attracts numerous discussion, however, the synergetic effect between them is hardly explored. Herein, we design a facial strategy to synthesize N,P-doped defective carbon nanosheets first (N,P-DC), then cover doped sites with well-define metal-N4 macrocyclic molecules (FePc@N,P-DC) through non-pyrolysis process. The defective carbon boosts the high spin state of Fe center, thus brings superior ORR performances with the half-wave potential of 0.903 V and excellent cycling-life stability in alkaline media. Theoretical calculations show that the overpotential of FePc@N,P-DC for ORR is 0.52 V, much lower than 0.80 V (N,P-DC). Interestingly, the OER activity is simultaneously improved. This metal-Pc@defective carbon hybrid opens a door to develop electrocatalysts combining atomically metal-N4 sites with topological defect towards diverse energy conversion type.

185 citations

Journal ArticleDOI
TL;DR: In this article, a stability test for both bare and hydrogenated FeP nanoparticles in the hydrogen evolution reaction (HER) was conducted and it was shown that hydrogenation improved the HER performance by reducing the surface-charge-transfer resistance, overpotential, and Tafel slope.
Abstract: Iron phosphide (FeP) has been recently demonstrated as a very attractive electrocatalyst for the hydrogen evolution reaction (HER). However, the understanding of its properties is far from satisfactory. Herein, we report the HER performance of FeP nanoparticles is enhanced after a stability test due to reduced surface-charge-transfer resistance in the HER process. The synthetic temperature and reactant ratio are important for surface-charge-transfer resistance, the electrochemically active surface area, and HER activity. Hydrogenation apparently improves the HER performance of FeP nanoparticles by reducing the surface-charge-transfer resistance, overpotential, and Tafel slope. Enhanced HER performance is observed after a stability test for both bare and hydrogenated FeP nanoparticles in the HER due to reduced surface-charge-transfer resistance. Thus, this study may enrich our knowledge and understanding to advance HER catalysis for electrochemical hydrogen generation.

185 citations

Journal ArticleDOI
Zhipeng Liu1, Zhichao Gao1, Yuhua Liu1, Maosheng Xia1, Runwei Wang1, Nan Li1 
TL;DR: The locally introduced 1T-phase MoS2 can not only contribute more active sites but also markedly promote the electronic conductivity and exhibit remarkable performance for the hydrogen evolution reaction with a small overpotential, a small Tafel slope of 61 mV/decade, and robust stability.
Abstract: As an electrocatalyst, conventional 2H-phase MoS2 suffers from limited active sites and inherently low electroconductivity. Phase transitions from 2H to 1T have been proposed as an effective strategy for optimization of the catalytic activity. However, complicated chemical exfoliation is generally involved. Here, MoS2 heterogeneous-phase nanosheets with a 1T phase (1T/2H-MoS2) generated in situ were prepared through a facile hydrothermal method. The locally introduced 1T-phase MoS2 can not only contribute more active sites but also markedly promote the electronic conductivity. Because of this unique structure, the as-synthesized 1T/2H-MoS2 nanosheets exhibit remarkable performance for the hydrogen evolution reaction with a small overpotential of 220 mV at 10 mA/cm2, a small Tafel slope of 61 mV/decade, and robust stability. This work facilitates the development of a two-dimensional heterogeneous nanostructure with enhanced applications.

185 citations

Journal ArticleDOI
TL;DR: In this article, an ultrathin Ni-Bi layer on a metallic Ni3N nanosheet array supported on a Ti mesh (Ni3N@Ni-Bi NS/Ti) was developed for water oxidation at near neutral pH.
Abstract: It is of great importance but still remains a key challenge to develop non-noble-metal bifunctional catalysts for efficient full water splitting under mild pH conditions. In this communication, we report the in situ electrochemical development of an ultrathin Ni–Bi layer on a metallic Ni3N nanosheet array supported on a Ti mesh (Ni3N@Ni–Bi NS/Ti) as a durable 3D core/shell structured nanoarray electrocatalyst for water oxidation at near-neutral pH. The Ni3N@Ni–Bi NS/Ti demands overpotentials of 405 and 382 mV to deliver a geometrical catalytic current density of 10 mA cm−2 in 0.1 and 0.5 M K–Bi (pH: 9.2), respectively, superior in activity to Ni3N NS/Ti and most reported non-precious metal catalysts under benign conditions. It also performs efficiently for the hydrogen evolution reaction requiring an overpotential of 265 mV for 10 mA cm−2 and its two-electrode electrolyser affords 10 mA cm−2 at a cell voltage of 1.95 V in 0.5 M K–Bi at 25 °C.

185 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