scispace - formally typeset
Search or ask a question
Topic

Overpotential

About: Overpotential is a research topic. Over the lifetime, 16474 publications have been published within this topic receiving 616632 citations.


Papers
More filters
Journal ArticleDOI
TL;DR: In this article, a facile cation doping combined with plasma reduction strategy was used to generate heterostructured Ni nanoparticles/V-doped NiFe LDH nanosheet array with multiple vacancies, exhibiting excellent hydrogen evolution reaction (HER) and overall water splitting performance.
Abstract: NiFe layered double hydroxides (LDHs) have been intensively investigated as promising electrocatalysts for oxygen evolution reaction. However, their hydrogen evolution reaction (HER) and overall water splitting performance are not satisfactory. Herein, we report a facile cation doping combined with plasma reduction strategy to generate heterostructured Ni nanoparticles/V-doped NiFe LDH nanosheet array with multiple vacancies, exhibiting excellent HER performance with a small overpotential of 19 mV at 10 mA cm−2. Moreover, when evaluated as bi-functional electrocatalyst for overall water splitting, a small cell voltage (1.43 V at 10 mA cm−2) and ultralong stability (over 1000 h) are achieved. Density functional theory (DFT) calculations reveal that V-doping, oxygen vacancy (Ov), Ni vacancy (Niv), and Ni nanoparticles can effectively improve the conductivity and optimize the hydrogen adsorption, Ov, Niv, and Ni nanoparticles help to facilitate H2O adsorption and dissociation progress in HER, the V-doping and Ov can efficiently reduce the energy barrier of O* in OER, and Ni/NiFe LDH heterostructure ameliorates the electronic structure and tunes electron transfer route.

213 citations

Journal ArticleDOI
TL;DR: In this paper, the electrolysis of CO2 to syngas (CO + H2) using nonprecious metal electrocatalysts was studied in bipolar membrane-based electrochemical cells.
Abstract: The electrolysis of CO2 to syngas (CO + H2) using nonprecious metal electrocatalysts was studied in bipolar membrane-based electrochemical cells. Electrolysis was carried out using aqueous bicarbonate and humidified gaseous CO2 on the cathode side of the cell, with Ag or Bi/ionic liquid cathode electrocatalysts. In both cases, stable currents were observed over a period of hours with an aqueous alkaline electrolyte and NiFeOx electrocatalyst on the anode side of the cell. In contrast, the performance of the cells degraded rapidly when conventional anion- and cation-exchange membranes were used in place of the bipolar membrane. In agreement with earlier reports, the Faradaic efficiency for CO2 reduction to CO was high at low overpotential. In the liquid-phase bipolar membrane cell, the Faradaic efficiency was stable at about 50% at 30 mA/cm2 current density. In the gas-phase cell, current densities up to 200 mA/cm2 could be obtained, albeit at lower Faradaic efficiency for CO production. At low overpotenti...

213 citations

Journal ArticleDOI
TL;DR: It is shown that the structurally precise ligand-protected Cu-hydride nanoclusters, such as Cu32H20L12 (L is a dithiophosphate ligand), offer unique selectivity for electrocatalytic CO2 reduction at low overpotentials.
Abstract: Copper electrocatalysts can reduce CO2 to hydrocarbons at high overpotentials. However, a mechanistic understanding of CO2 reduction on nanostructured Cu catalysts has been lacking. Herein we show that the structurally precise ligand-protected Cu-hydride nanoclusters, such as Cu32H20L12 (L is a dithiophosphate ligand), offer unique selectivity for electrocatalytic CO2 reduction at low overpotentials. Our density functional theory (DFT) calculations predict that the presence of the negatively charged hydrides in the copper cluster plays a critical role in determining the selectivity of the reduction product, yielding HCOOH over CO with a lower overpotential. The HCOOH formation proceeds via the lattice-hydride mechanism: first, surface hydrides reduce CO2 to HCOOH product, and then the hydride vacancies are readily regenerated by the electrochemical proton reduction. DFT calculations further predict that hydrogen evolution is less competitive than HCOOH formation at the low overpotential. Confirming the pr...

213 citations

Journal ArticleDOI
TL;DR: It is demonstrated that the electrocatalytic activity of manganese-based heterogeneous catalyst can be significantly improved through halogen and nitrogen dual-coordination to modulate the electronic structure ofManganese atom.
Abstract: Developing highly efficient electrocatalysts based on cheap and earth-abundant metals for CO2 reduction is of great importance. Here we demonstrate that the electrocatalytic activity of manganese-based heterogeneous catalyst can be significantly improved through halogen and nitrogen dual-coordination to modulate the electronic structure of manganese atom. Such an electrocatalyst for CO2 reduction exhibits a maximum CO faradaic efficiency of 97% and high current density of ~10 mA cm−2 at a low overpotential of 0.49 V. Moreover, the turnover frequency can reach 38347 h−1 at overpotential of 0.49 V, which is the highest among the reported heterogeneous electrocatalysts for CO2 reduction. In situ X-ray absorption experiment and density-functional theory calculation reveal the modified electronic structure of the active manganese site, on which the free energy barrier for intermediate formation is greatly reduced, thus resulting in a great improvement of CO2 reduction performance. While renewable CO2 conversion provides a means to remove and recycle waste emissions, there are few earth-abundant materials that are both efficient and active. Here, authors prepare N-doped carbon with atomic manganese as high-performance CO2 reduction electrocatalyst.

212 citations

Journal ArticleDOI
TL;DR: In this paper, N-doped cobalt pyrite (CoS2) electrocatalytic material is developed via utilizing the synergic effect of N dopants and S vacancies.
Abstract: Here, N-doped cobalt pyrite (CoS2) electrocatalytic material is developed via utilizing the synergic effect of N dopants and S vacancies. The catalyst displays high activity and stability for hydrogen evolution reaction. Density functional theory calculations and electrochemical characterizations reveal that the electrochemical activity of the CoS2 catalyst is directly associated with the content of N dopants and S vacancies, where proper combinations of N dopants and S vacancies yield a minimized overpotential close to that of commercial Pt. What’s more, optimized performance has been achieved by carefully manipulating the amounts of N dopants and S vacancies in N-doped CoS2 catalyst, which exhibits a Tafel slope as small as 48 mV/dec, an ultralow overpotential of 57 mV at 10 mA/cm2, and satisfying stability. This work highlights a feasible strategy to explore efficient electrocatalysts via nonmetal element doping and defect engineering.

212 citations


Network Information
Related Topics (5)
Graphene
144.5K papers, 4.9M citations
89% related
Nanoparticle
85.9K papers, 2.6M citations
89% related
Carbon nanotube
109K papers, 3.6M citations
88% related
Oxide
213.4K papers, 3.6M citations
88% related
Catalysis
400.9K papers, 8.7M citations
87% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20232,316
20224,268
20212,838
20202,411
20192,174
20181,740