Interfacial synergy of ultralong jagged Pt85Mo15–S nanowires with abundant active sites on enhanced hydrogen evolution in an alkaline solution

2019 ◽  
Vol 7 (42) ◽  
pp. 24328-24336 ◽  
Author(s):  
Yao Wang ◽  
Hongying Zhuo ◽  
Xin Zhang ◽  
Yunrui Li ◽  
Juntao Yang ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Alkaline Solution ◽  
Active Sites ◽  
Synergistic Effects

Ultralong jagged PtMo–S nanowires with rich “interfacial active sites” were fabricated by using S as the “active auxiliary” to demonstrate the enhanced catalytic HER performance triggered by the electronic and synergistic effects of PtMo/MoSx.

scholarly journals In Situ Construction of Ag/TiO2/g-C3N4 Heterojunction Nanocomposite Based on Hierarchical Co-Assembly with Sustainable Hydrogen Evolution

Nanomaterials ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 1 ◽  
Author(s):  
Rui Geng ◽  
Juanjuan Yin ◽  
Jingxin Zhou ◽  
Tifeng Jiao ◽  
Yao Feng ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Self Assembly ◽  
Active Sites ◽  
Carrier Transport ◽  
Synergistic Effects ◽  
Electron Hole ◽  
Simple Strategy ◽  
Promising Strategy ◽  
Catalytic Active Sites

The construction of heterojunctions provides a promising strategy to improve photocatalytic hydrogen evolution. However, how to fabricate a nanoscale TiO2/g-C3N4 heterostructure and hinder the aggregation of bulk g-C3N4 using simple methods remains a challenge. In this work, we use a simple in situ construction method to design a heterojunction model based on molecular self-assembly, which uses a small molecule matrix for self-integration, including coordination donors (AgNO3), inorganic titanium source (Ti(SO4)2) and g-C3N4 precursor (melamine). The self-assembled porous g-C3N4 nanotube can hamper carrier aggregation and it provides numerous catalytic active sites, mainly via the coordination of Ag+ ions. Meanwhile, the TiO2 NPs are easily mineralized on the nanotube template in dispersive distribution to form a heterostructure via an N–Ti bond of protonation, which contributes to shortening the interfacial carrier transport, resulting in enhanced electron-hole pairs separation. Originating from all of the above synergistic effects, the obtained Ag/TiO2/g-C3N4 heterogenous photocatalysts exhibit an enhanced H2 evolution rate with excellent sustainability 20.6-fold-over pure g-C3N4. Our report provides a feasible and simple strategy to fabricate a nanoscale heterojunction incorporating g-C3N4, and has great potential in environmental protection and water splitting.

scholarly journals Facile Synthesis of 1T-Phase MoS2 Nanosheets on N-Doped Carbon Nanotubes towards Highly Efficient Hydrogen Evolution

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3273
Author(s):  
Kunjie Wang ◽  
Jiahui Zhang ◽  
Yachen Ye ◽  
Hongbin Ma ◽  
Bingxin Liu ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Active Sites ◽  
High Performance ◽  
Synergistic Effects ◽  
Hydrothermal Process ◽  
Mos2 Nanosheets ◽  
Facile Synthesis ◽  
New Strategy

1T-phase molybdenum disulfide is supposed to be one of the non-precious metal-based electrocatalysts for the hydrogen evolution reaction with the highest potential. Herein, 1T-MoS2 nanosheets were anchored on N-doped carbon nanotubes by a simple hydrothermal process with the assistance of urea promotion transition of the 1T phase. Based on the 1T-MoS2 nanosheets anchored on the N-doped carbon nanotubes structures, 1T-MoS2 nanosheets can be said to have highly exposed active sites from edges and the basal plane, and the dopant N in carbon nanotubes can promote electron transfer between N-doped carbon nanotubes and 1T-MoS2 nanosheets. With the synergistic effects of this structure, the excellent 1T-MoS2/ N-doped carbon nanotubes catalyst has a small overpotential of 150 mV at 10 mA cm−2, a relatively low Tafel slope of 63 mV dec−1, and superior stability. This work proposes a new strategy to design high-performance hydrogen evolution reaction catalysts.

Engineering of Ru/Ru2P interfaces superior to Pt active sites for catalysis of the alkaline hydrogen evolution reaction

2019 ◽  
Vol 7 (10) ◽  
pp. 5621-5625 ◽  
Author(s):  
Zhao Liu ◽  
Zhe Li ◽  
Jing Li ◽  
Jie Xiong ◽  
Shunfa Zhou ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Active Sites ◽  
Synergistic Effects ◽  
Water Dissociation ◽  
Proton Reduction ◽  
Mass Activity

Based on the synergistic effects of Ru on water dissociation and Ru2P on proton reduction, Ru/Ru2P interfaces were engineered in situ, and the mass activity of the new catalyst for the alkaline HER was doubled compared to Pt/C.

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.

scholarly journals The Synergistic Effects of Alloying on the Performance and Stability of Co3Mo and Co7Mo6 for the Electrocatalytic Hydrogen Evolution Reaction

Hydrogen ◽  
2020 ◽  
Vol 1 (1) ◽  
pp. 11-21
Author(s):  
Youyi Sun ◽  
Alexey Y. Ganin
Keyword(s):  
Hydrogen Evolution ◽  
Synergistic Effects ◽  
Alkaline Media ◽  
Price Of Stability ◽  
X Ray Diffraction ◽  
Free Standing ◽  
X Ray ◽  
Current Decay ◽  
Earth Abundant ◽  
Current Densities

Metal alloys have become a ubiquitous choice as catalysts for electrochemical hydrogen evolution in alkaline media. However, scarce and expensive Pt remains the key electrocatalyst in acidic electrolytes, making the search for earth-abundant and cheaper alternatives important. Herein, we present a facile and efficient synthetic route towards polycrystalline Co3Mo and Co7Mo6 alloys. The single-phased nature of the alloys is confirmed by X-ray diffraction and electron microscopy. When electrochemically tested, they achieve competitively low overpotentials of 115 mV (Co3Mo) and 160 mV (Co7Mo6) at 10 mA cm−2 in 0.5 M H2SO4, and 120 mV (Co3Mo) and 160 mV (Co7Mo6) at 10 mA cm−2 in 1 M KOH. Both alloys outperform Co and Mo metals, which showed significantly higher overpotentials and lower current densities when tested under identical conditions, confirming the synergistic effect of the alloying. However, the low overpotential in Co3Mo comes at the price of stability. It rapidly becomes inactive when tested under applied potential bias. On the other hand, Co7Mo6 retains the current density over time without evidence of current decay. The findings demonstrate that even in free-standing form and without nanostructuring, polycrystalline bimetallic electrocatalysts could challenge the dominance of Pt in acidic media if ways for improving their stability were found.

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.

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