Engineering stepped edge surface structures of MoS<sub>2</sub>sheet stacks to accelerate the hydrogen evolution reaction

Hu, Jue; Huang, Bolong; Zhang, Chengxu; Wang, Zilong; An, Yiming; Zhou, Dan; Lin, He; Leung, Michael K.H.; Yang, Shihe

doi:10.1039/c6ee03629e

Cited by 293 publications

(174 citation statements)

References 64 publications

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“…[11] Therefore, the Volmer reaction is the key step in HER and it is strongly dependent on the electron transfer, the density of active sites, and the Gibbs free energy of adsorbed atomic hydrogen. [3,4,7,[16][17][18] Among them, the enhancement mechanism through improving conductivity is still unclear, possibly due to the complicated model system with varying factors like active site or nanostructures. [3,4,7,[16][17][18] Among them, the enhancement mechanism through improving conductivity is still unclear, possibly due to the complicated model system with varying factors like active site or nanostructures.…”

Section: Introductionmentioning

confidence: 99%

Reversing Interfacial Catalysis of Ambipolar WSe₂ Single Crystal

Wang

et al. 2019

Advanced Science

110

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An improved understanding of the origin of the electrocatalytic activity is of importance to the rational design of highly efficient electrocatalysts for the hydrogen evolution reaction. Here, an ambipolar single‐crystal tungsten diselenide (WSe2) semiconductor is employed as a model system where the conductance and carrier of WSe2 can be individually tuned by external electric fields. The field‐tuned electrochemical microcell is fabricated based on the single‐crystal WSe2 and the catalytic activity of the WSe2 microcell is measured versus the external electric field. Results show that WSe2 with electrons serving as the dominant carrier yields much higher activity than WSe2 with holes serving as the dominant carrier even both systems exhibit similar conductance. The catalytic activity enhancement can be characterized by the Tafel slope decrease from 138 to 104 mV per decade, while the electron area concentration increases from 0.64 × 1012 to 1.72 × 1012 cm−2. To further understand the underlying mechanism, the Gibbs free energy and charge distribution for adsorbed hydrogen on WSe2 versus the area charge concentration is systematically computed, which is in line with experiments. This comprehensive study not only sheds light on the mechanism underlying the electrocatalysis processes, but also offers a strategy to achieve higher electrocatalytic activity.

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Section: Introductionmentioning

confidence: 99%

Reversing Interfacial Catalysis of Ambipolar WSe₂ Single Crystal

Wang

et al. 2019

Advanced Science

110

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“…As summarized in Figure S9 (Supporting Information), the capacitance increased from PCM 400 to PCM 530, followed by continuous drop in PCMs annealed at higher temperatures. The EDLC drop by increasing annealing temperature is related to the larger MoS 2 particle size and high crystallinity (Figure S4, Supporting Information), indicating that surface area to attend electrochemical reaction decreased . However, because the signals from (active) edges, (less‐active) basal planes of MoS 2 and carbon cannot be deconvoluted in EDLC measurements, the capacitance values could not be correlated to the number of active sites directly.…”

Section: Resultsmentioning

confidence: 99%

Edge‐Terminated MoS₂ Nanoassembled Electrocatalyst via In Situ Hybridization with 3D Carbon Network

Chung

Yoo

Park

et al. 2018

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Transition metal dichalcogenides, especially MoS , are considered as promising electrocatalysts for hydrogen evolution reaction (HER). Since the physicochemical properties of MoS and electrode morphology are highly sensitive factor for HER performance, designed synthesis is highly pursued. Here, an in situ method to prepare a 3D carbon/MoS hybrid catalyst, motivated by the graphene ribbon synthesis process, is reported. By rational design strategies, the hybrid electrocatalysts with cross-connected porous structure are obtained, and they show a high HER activity even comparable to the state-of-the-art MoS catalyst without appreciable activity loss in long-term operations. Based on various physicochemical techniques, it is demonstrated that the synthetic procedure can effectively guide the formation of active site and 3D structure with a distinctive feature; increased exposure of active sites by decreased domain size and intrinsically high activity through controlling the number of stacking layers. Moreover, the importance of structural properties of the MoS -based catalysts is verified by controlled experiments, validating the effectiveness of the designed synthesis approach.

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“…When these methods are conducted on transition metal dichalcogenide (MoS 2 as the typical example), abundant edge active sites could be effectively generated and the HER performance would be improved. Furthermore, Yang and co‐workers used a microwave hydrothermal method with prolonged reaction time to prepare a stepped edge surface terminated structure of MoS 2 sheets, as shown in Figure c,d . With this fantastic structure, the electrocatalyst exhibits robust HER catalytic activity in 0.5 m H 2 SO 4 with an overpotential of 104 mV to reach the current density of 10 mA cm −2 , and an exchange current density of 0.2 mA cm −2 , which is superior to that of the flat edge surface of MoS 2 .…”

Section: Creating More Active Sitesmentioning

confidence: 86%

Section: Creating More Active Sitesmentioning

confidence: 99%

Rational Design of Transition Metal‐Based Materials for Highly Efficient Electrocatalysis

2018

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Electrocatalysts play critical roles in the renewable electrochemical energy storage and conversion systems. The conventional noble metal‐based electrocatalysts cannot satisfy the demand of large‐scale manufacturing due to their high‐price and scarce reserves in the earth. Therefore, rational designing of transition metal‐based materials to endow high activity, selectivity, stability, and low cost has been regarded as an alternative of noble metal‐based materials. Here, recent effective and facile strategies to rationally design transition metal‐based electrocatalysts, such as increasing the number active sties, improving the utilization of active sites (atomic‐scale catalysts), modulating the electron configurations, as well as controlling the lattice facets, for oxygen reduction reaction, oxygen evolution reaction, hydrogen evolution reaction, and CO2 reduction reaction, are summarized. It is believed that based on the understanding of fundamental design principles, well‐designed non‐noble metal and even metal free electrocatalysts would further make the electrochemical energy conversion and storage great promise in the future.

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Engineering stepped edge surface structures of MoS₂sheet stacks to accelerate the hydrogen evolution reaction

Abstract: Significantly enhanced HER kinetics were achieved by controllably fabricating a stepped MoS2 surface structure which possesses more optimal free energy of H-adsorption.

Cited by 293 publications

References 64 publications

Reversing Interfacial Catalysis of Ambipolar WSe₂ Single Crystal

Reversing Interfacial Catalysis of Ambipolar WSe₂ Single Crystal

Edge‐Terminated MoS₂ Nanoassembled Electrocatalyst via In Situ Hybridization with 3D Carbon Network

Rational Design of Transition Metal‐Based Materials for Highly Efficient Electrocatalysis

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Engineering stepped edge surface structures of MoS2sheet stacks to accelerate the hydrogen evolution reaction

Abstract: Significantly enhanced HER kinetics were achieved by controllably fabricating a stepped MoS2 surface structure which possesses more optimal free energy of H-adsorption.

Cited by 293 publications

References 64 publications

Reversing Interfacial Catalysis of Ambipolar WSe2 Single Crystal

Reversing Interfacial Catalysis of Ambipolar WSe2 Single Crystal

Edge‐Terminated MoS2 Nanoassembled Electrocatalyst via In Situ Hybridization with 3D Carbon Network

Rational Design of Transition Metal‐Based Materials for Highly Efficient Electrocatalysis

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Engineering stepped edge surface structures of MoS₂sheet stacks to accelerate the hydrogen evolution reaction

Reversing Interfacial Catalysis of Ambipolar WSe₂ Single Crystal

Reversing Interfacial Catalysis of Ambipolar WSe₂ Single Crystal

Edge‐Terminated MoS₂ Nanoassembled Electrocatalyst via In Situ Hybridization with 3D Carbon Network