Seamless Separation of OHad and Had on a Ni-O Catalyst Toward Exceptional Alkaline Hydrogen Evolution

2022 ◽  
Author(s):  
Jiangtian Li ◽  
Deryn Chu ◽  
David R Baker ◽  
Rongzhong Jiang
Keyword(s):  
Hydrogen Evolution ◽  
Active Sites ◽  
Atomic Scale

A seamless separation of intermediates (OHad and Had) to different active sites at atomic scale is realized on a Ni-O catalyst that is functionalized with low-coordinated oxygen and abundant vacancies....

Modeling the active sites of Co-promoted MoS2 particles by DFT

2017 ◽  
Vol 19 (3) ◽  
pp. 2017-2024 ◽  
Author(s):  
Manuel Šarić ◽  
Jan Rossmeisl ◽  
Poul Georg Moses
Keyword(s):  
Hydrogen Evolution ◽  
Active Sites ◽  
Scale Structure ◽  
Atomic Scale ◽  
Dft Simulations ◽  
Atomic Scale Structure

The atomic-scale structure of CoMoS and the nature of its active sites for hydrodesulfurization and hydrogen evolution are determined based on DFT simulations.

What catalysis needs from the electron microscopist

1988 ◽  
Vol 46 ◽  
pp. 694-695
Author(s):  
Alexis T. Bell
Keyword(s):  
Active Sites ◽  
Heterogeneous Catalysts ◽  
Catalyst Deactivation ◽  
Surface Composition ◽  
Internal Surface ◽  
Active Phase ◽  
Atomic Scale ◽  
Metal Catalyst ◽  
Internal Surface Area ◽  
Porous Support

Heterogeneous catalysts, used in industry for the production of fuels and chemicals, are microporous solids characterized by a high internal surface area. The catalyticly active sites may occur at the surface of the bulk solid or of small crystallites deposited on a porous support. An example of the former case would be a zeolite, and of the latter, a supported metal catalyst. Since the activity and selectivity of a catalyst are known to be a function of surface composition and structure, it is highly desirable to characterize catalyst surfaces with atomic scale resolution. Where the active phase is dispersed on a support, it is also important to know the dispersion of the deposited phase, as well as its structural and compositional uniformity, the latter characteristics being particularly important in the case of multicomponent catalysts. Knowledge of the pore size and shape is also important, since these can influence the transport of reactants and products through a catalyst and the dynamics of catalyst deactivation.

Field Effect Modulation of Electrocatalytic Hydrogen Evolution at Back-Gated Two-Dimensional MoS2 Electrodes

2019 ◽  
Author(s):  
Yan Wang ◽  
Sagar Udyavara ◽  
Matthew Neurock ◽  
C. Daniel Frisbie
Keyword(s):  
Electric Field ◽  
Hydrogen Evolution ◽  
Active Sites ◽  
Density Functional ◽  
Electrode Materials ◽  
Density Functional Theory Calculations ◽  
Electronic Charge ◽  
Back Side ◽  
Gate Electrode ◽  
Conventional Manner

<div> <div> <div> <p> </p><div> <div> <div> <p>Electrocatalytic activity for hydrogen evolution at monolayer MoS2 electrodes can be enhanced by the application of an electric field normal to the electrode plane. The electric field is produced by a gate electrode lying underneath the MoS2 and separated from it by a dielectric. Application of a voltage to the back-side gate electrode while sweeping the MoS2 electrochemical potential in a conventional manner in 0.5 M H2SO4 results in up to a 140-mV reduction in overpotential for hydrogen evolution at current densities of 50 mA/cm2. Tafel analysis indicates that the exchange current density is correspondingly improved by a factor of 4 to 0.1 mA/cm2 as gate voltage is increased. Density functional theory calculations support a mechanism in which the higher hydrogen evolution activity is caused by gate-induced electronic charge on Mo metal centers adjacent the S vacancies (the active sites), leading to enhanced Mo-H bond strengths. Overall, our findings indicate that the back-gated working electrode architecture is a convenient and versatile platform for investigating the connection between tunable electronic charge at active sites and overpotential for electrocatalytic processes on ultrathin electrode materials.</p></div></div></div><br><p></p></div></div></div>

Boron-modulated surface of hollow nickel framework for improved hydrogen evolution

2021 ◽  
Author(s):  
Weishi Gu ◽  
Zhongqin Pan ◽  
Han Tao ◽  
Yanling Guo ◽  
Jun Pu ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Active Sites ◽  
Nano Structure ◽  
Binder Free ◽  
Structure Engineering

Taking advantage of micro/nano structure engineering and surface boron modulation, we developed a binder-free and support-free electrode to enrich and optimize active sites of Ni.

Abundant Active Sites on the Basal Plane and Edges of Layered van der Waals Fe3GeTe2 for Highly Efficient Hydrogen Evolution

2021 ◽  
pp. 313-319
Author(s):  
Amir A. Rezaie ◽  
Eunsoo Lee ◽  
Diana Luong ◽  
Johan A. Yapo ◽  
Boniface P. T. Fokwa
Keyword(s):  
Hydrogen Evolution ◽  
Basal Plane ◽  
Active Sites ◽  
Van Der Waals ◽  
Highly Efficient

scholarly journals Defect-Rich Heterogeneous MoS2/rGO/NiS Nanocomposite for Efficient pH-Universal Hydrogen Evolution

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 662 ◽  
Author(s):  
Guangsheng Liu ◽  
Kunyapat Thummavichai ◽  
Xuefeng Lv ◽  
Wenting Chen ◽  
Tingjun Lin ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Active Sites ◽  
Reduced Graphene ◽  
Heterogeneous Interfaces ◽  
Wide Ph Range ◽  
Ph Range ◽  
A Current ◽  
Poor Stability

Molybdenum disulfide (MoS2) has been universally demonstrated to be an effective electrocatalytic catalyst for hydrogen evolution reaction (HER). However, the low conductivity, few active sites and poor stability of MoS2-based electrocatalysts hinder its hydrogen evolution performance in a wide pH range. The introduction of other metal phases and carbon materials can create rich interfaces and defects to enhance the activity and stability of the catalyst. Herein, a new defect-rich heterogeneous ternary nanocomposite consisted of MoS2, NiS and reduced graphene oxide (rGO) are synthesized using ultrathin αNi(OH)2 nanowires as the nickel source. The MoS2/rGO/NiS-5 of optimal formulation in 0.5 M H2SO4, 1.0 M KOH and 1.0 M PBS only requires 152, 169 and 209 mV of overpotential to achieve a current density of 10 mA cm−2 (denoted as η10), respectively. The excellent HER performance of the MoS2/rGO/NiS-5 electrocatalyst can be ascribed to the synergistic effect of abundant heterogeneous interfaces in MoS2/rGO/NiS, expanded interlayer spacings, and the addition of high conductivity graphene oxide. The method reported here can provide a new idea for catalyst with Ni-Mo heterojunction, pH-universal and inexpensive hydrogen evolution reaction electrocatalyst.

An efficient CoS2/CoSe2 hybrid catalyst for electrocatalytic hydrogen evolution

2017 ◽  
Vol 5 (6) ◽  
pp. 2504-2507 ◽  
Author(s):  
Yaxiao Guo ◽  
Changshuai Shang ◽  
Erkang Wang
Keyword(s):  
Hydrogen Evolution ◽  
Electrocatalytic Activity ◽  
Active Sites ◽  
High Dispersion ◽  
Hybrid Catalyst

The CoS2/CoSe2 hybrid catalyst exhibits superior HER electrocatalytic activity as well as excellent electrochemical durability. CoSe2/DETA nanobelts not only afford an interconnected conducting network, but also demonstrate superior HER electrocatalytic activity. High dispersion and smaller CoS2 nanoparticles on the surface can provide abundant active sites for the HER.

scholarly journals Engineering single-atomic ruthenium catalytic sites on defective nickel-iron layered double hydroxide for overall water splitting

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Panlong Zhai ◽  
Mingyue Xia ◽  
Yunzhen Wu ◽  
Guanghui Zhang ◽  
Junfeng Gao ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Water Splitting ◽  
Layered Double Hydroxide ◽  
Hydrogen Evolution Reaction ◽  
Active Sites ◽  
Density Functional ◽  
Rational Design ◽  
Single Atom ◽  
Nickel Iron ◽  
Double Hydroxide

AbstractRational design of single atom catalyst is critical for efficient sustainable energy conversion. However, the atomic-level control of active sites is essential for electrocatalytic materials in alkaline electrolyte. Moreover, well-defined surface structures lead to in-depth understanding of catalytic mechanisms. Herein, we report a single-atomic-site ruthenium stabilized on defective nickel-iron layered double hydroxide nanosheets (Ru1/D-NiFe LDH). Under precise regulation of local coordination environments of catalytically active sites and the existence of the defects, Ru1/D-NiFe LDH delivers an ultralow overpotential of 18 mV at 10 mA cm−2 for hydrogen evolution reaction, surpassing the commercial Pt/C catalyst. Density functional theory calculations reveal that Ru1/D-NiFe LDH optimizes the adsorption energies of intermediates for hydrogen evolution reaction and promotes the O–O coupling at a Ru–O active site for oxygen evolution reaction. The Ru1/D-NiFe LDH as an ideal model reveals superior water splitting performance with potential for the development of promising water-alkali electrocatalysts.

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