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.

scholarly journals Flower-Like Dual-Defective Z-Scheme Heterojunction g-C3N4/ZnIn2S4 High-Efficiency Photocatalytic Hydrogen Evolution and Degradation of Mixed Pollutants

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2483
Author(s):  
Linlin Hou ◽  
Zhiliang Wu ◽  
Chun Jin ◽  
Wei Li ◽  
Qiuming Wei ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Active Sites ◽  
High Efficiency ◽  
Three Dimensional ◽  
Photogenerated Electron ◽  
Mixed Solution ◽  
Defect Engineering ◽  
Nano Structure ◽  
Photocatalytic Hydrogen Evolution ◽  
Degradation Rates

Graphitic carbon nitride (g-C3N4) with a porous nano-structure, nitrogen vacancies, and oxygen-doping was prepared by the calcination method. Then, it was combined with ZnIn2S4 nanosheets containing zinc vacancies to construct a three-dimensional (3D) flower-like Z-scheme heterojunction (pCN-N/ZIS-Z), which was used for photocatalytic hydrogen evolution and the degradation of mixed pollutants. The constructed Z-scheme heterojunction improved the efficiency of photogenerated charges separation and migration, and the large surface area and porous characteristics provided more active sites. Doping and defect engineering can change the bandgap structure to improve the utilization of visible light, and can also capture photogenerated electrons to inhibit recombination, so as to promote the use of photogenerated electron-hole pairs in the photocatalytic redox process. Heterojunction and defect engineering synergized to form a continuous and efficient conductive operation framework, which achieves the hydrogen production of pCN-N/ZIS-Z (9189.8 µmol·h−1·g−1) at 58.9 times that of g-C3N4 (155.9 µmol·h−1·g−1), and the degradation rates of methyl orange and metronidazole in the mixed solution were 98.7% and 92.5%, respectively. Our research provides potential ideas for constructing a green and environmentally friendly Z-scheme heterojunction catalyst based on defect engineering to address the energy crisis and environmental restoration.

scholarly journals Insertion of Platinum Nanoparticles into MoS2 Nanoflakes for Enhanced Hydrogen Evolution Reaction

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1520 ◽  
Author(s):  
Dan Li ◽  
Yang Li ◽  
Bowei Zhang ◽  
Yu Lui ◽  
Sivaprasad Mooni ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Catalytic Activity ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Active Sites ◽  
Rational Design ◽  
Counter Electrode ◽  
Pt Nanoparticles ◽  
Stainless Steel Mesh ◽  
Binder Free

Pt as a chemical inert metal has been widely applied as the counter electrode in various electrochemical measurements. However, it can also be dissolved and redeposit to the working electrode under certain electrochemical circumstances. Herein we demonstrated a cyclic voltammetry (CV) cycling method to synthesize a catalyst comprising inserted Pt nanoparticles into MoS2 nanoflake stack structures on stainless steel mesh (SSM). The binder-free composite structure exhibits significantly enhanced hydrogen evolution reaction (HER) catalytic activity with an overpotentials of 87 mV at 10 mA cm−2. The deposited Pt nanoparticles significantly enhance the catalytic activity through changing the structure of MoS2 and increasing the amount of active sites. This work provides a new way forward for rational design of the nano-electrocatalysts.

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>

Electronic structure engineering of single atomic Ru by Ru nanoparticles to enable enhanced activity for alkaline water reduction

2019 ◽  
Vol 7 (33) ◽  
pp. 19531-19538 ◽  
Author(s):  
Qi Hu ◽  
Guomin Li ◽  
Xiaowan Huang ◽  
Ziyu Wang ◽  
Hengpan Yang ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Electronic Structures ◽  
Alkaline Water ◽  
Water Reduction ◽  
Ru Nanoparticles ◽  
Enhanced Activity ◽  
Structure Engineering

The electronic structures of single atomic Ru (SA-Ru) were suitably optimized by nearby Ru NPs for boosting the hydrogen evolution reaction (HER) over SA-Ru.

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.

Hollow structure engineering of FeCo alloy nanoparticles electrospun in nitrogen-doped carbon enables high performance flexible all-solid-state zinc–air batteries

2020 ◽  
Vol 4 (4) ◽  
pp. 1747-1753 ◽  
Author(s):  
Yuanyuan Ma ◽  
Wenjie Zang ◽  
Afriyanti Sumboja ◽  
Lu Mao ◽  
Ximeng Liu ◽  
...  
Keyword(s):  
Active Sites ◽  
High Performance ◽  
Hollow Structure ◽  
Active Surface ◽  
Oxygen Electrode ◽  
Active Surface Area ◽  
Active Components ◽  
Nitrogen Doped Carbon ◽  
Structure Engineering ◽  
Kinetics Of

Hollow structuring of active components is an effective strategy to improve the kinetics of oxygen electrode catalysts, arising from the increased the active surface area, the defects on the exposed surface, and the accessible active sites.

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