skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: Atomically engineering activation sites onto metallic 1T-MoS2 catalysts for enhanced electrochemical hydrogen evolution
Engineering catalytic sites at the atomic level provide an opportunity to understand the catalyst’s active sites, which is vital to the development of improved catalysts. Herein, we show a reliable and tunable polyoxometalate (POM) template-based synthetic strategy to atomically engineer metal doping sites onto metallic 1T-MoS2, using Anderson-type POMs (XMo6, X = FeIII, CoIII, or NiII) as precursors. Benefiting from the synergistic effect of doping metals into 1T-MoS2 and the possible tuning effect of the Ni-O-Mo bond, the optimized Ni and O incorporated 1T-MoS2 (NiO@1T-MoS2) catalyst excels in the hydrogen evolution reaction (HER). With a positive onset potential of ~ 0 V and a low overpotential of -46 mV in 1.0 M KOH, its results are comparable to 20% Pt/C. First-principles calculations reveal co-doping Ni and O into 1T-MoS2 assists the processes of both water dissociation and hydrogen generation from their intermediate states. This research will expand on the ability to improve the activities of various catalysts by precisely engineering atomic activation sites to achieve significant electronic modulations and improve atomic utilization efficiencies.  more » « less
Award ID(s):
1704992
PAR ID:
10093792
Author(s) / Creator(s):
; ; ; ; ; ;
Date Published:
Journal Name:
Nature communications
Volume:
10
Issue:
982
ISSN:
2041-1723
Page Range / eLocation ID:
1-11
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; ; ; ; ; ; ; et al (, Nature Communications)
    Abstract 1T-MoS2and single-atom modified analogues represent a highly promising class of low-cost catalysts for hydrogen evolution reaction (HER). However, the role of single atoms, either as active species or promoters, remains vague despite its essentiality toward more efficient HER. In this work, we report the unambiguous identification of Ni single atom as key active sites in the basal plane of 1T-MoS2(Ni@1T-MoS2) that result in efficient HER performance. The intermediate structure of this Ni active site under catalytic conditions was captured by in situ X-ray absorption spectroscopy, where a reversible metallic Ni species (Ni0) is observed in alkaline conditions whereas Ni remains in its local structure under acidic conditions. These insights provide crucial mechanistic understanding of Ni@1T-MoS2HER electrocatalysts and suggest that the understanding gained from such in situ studies is necessary toward the development of highly efficient single-atom decorated 1T-MoS2electrocatalysts. 
    more » « less
  2. (, 2D materials)
    Recently, the fabricated MoS2 field effect transistors (FETs) with 1T-MoS2 electrodes exhibit excellent performance with rather low contact resistance, as compared with those with metals deposited directly on 2H-MoS2 (Kappera et al 2014 Nat. Mater. 13 1128), but the reason for that remains elusive. By means of density functional theory calculations, we investigated the carrier injection at the 1T/2H MoS2 interface and found that although the Schottky barrier height (SBH) values of 1T/2H MoS2 interfaces can be tuned by controlling the stacking patterns, the p-type SBH values of 1T/2H MoS2 interfaces with different stackings are lower than their corresponding n-type SBH values, which demonstrated that the metallic 1T phase can be used as an efficient hole injection layer for 2H-MoS2. In addition, as compared to the n-type Au/MoS2 and Pd/MoS2 contacts, the p-type SBH values of 1T/2H MoS2 interfaces are much lower, which stem from the efficient hole injection between 1T-MoS2 and 2H-MoS2. This can explain the low contact resistance in the MoS2 FETs with 1T-MoS2 electrodes. Notably, the SBH values can be effectively modulated by an external electric field, and a significantly low p-type SBH value can be achieved under an appropriate electric field. We also demonstrated that this approach is also valid for WS2, WSe2 and MoSe2 systems, which indicates that the method can most likely be extended to other TMDs, and thus may open new promising avenues of contact engineering in these materials. 
    more » « less
  3. ; ; ; ; ; ; ; ; ; (, Steel in translation)
    Ni/SBA-15 meso-structured catalysts modified with chromium and CeO2 (Ni–Cr-CeO2/SBA-15) were utilized to produce hydrogen from glycerol steam reforming (GSR). The catalysts were synthesized by a one-pot hydrothermal process and extensively characterized by analytical techniques such as N2 adsorption–desorption (BET), H2-temperature programmed reduction (H2-TPR), powder X-ray diffraction (PXRD), inductively coupled plasma-optical emission spectrometry (ICP-OES), and transmission electron microscopy (TEM). The low-angle XRD reflections affirmed that the catalysts were crystalline and possessed a 2D-ordered porosity. The BET results depicted that all the catalysts exhibited a good surface area ranging from 633 to 792m2/g, and the pore sizes were consistently in the mesoporous range (between 3 and 5 nm). TEM analysis of both calcined and spent catalysts revealed that the metal active sites were embedded in the hybrid CeO2-SiO2 support. Overall, the Ni-based catalysts exhibited higher glycerol conversion -12Ni-SBA-15–99.9%, 12Ni3CeO2-SBA-15–89.4%, and 8Ni4Cr3CeO2-SBA-15–99.7%. Monometallic 12Ni/SBA-15 performed exceptionally well, while 12Cr/SBA-15 performed poorly with the highest 71.48% CO selectivity. For short-term GSR reactions, CeO2 addition to 12Ni/SBA-15 did not have any effect, whereas Cr addition resulted in a 32% decrease in H2 selectivity. The long-term stability studies of 12Ni-SBA-15 showed H2 selectivity of ~ 64% and ~ 98% glycerol conversion. However, its activity was short-lived. After 20–30 h, the H2 selectivity and conversion dropped precipitously to 40%. The doping of mesoporous Ni/SBA-15 with Cr and CeO2 remarkably enhanced the long-term stability of the catalyst for 12Ni3CeO2-SBA-15, and 8Ni4Cr3CeO2-SBA-15 catalyst which showed ~ 58% H2 selectivity and ~ 100% conversion for the entire 60 h. Interestingly, Cr and CeO2 seem to improve the shelf-life of Ni-SBA-15 via different mechanistic pathways. CeO2 mitigated Ni poisoning through coke oxidation whereas Cr bolstered the catalyst stability via maintaining a well-defined pore size, structural rigidity, and integrity of the heterogeneous framework, thereby restricting structural collapse, and hence retard sintering of the Ni active sites during the long-term 60 h of continuous reaction. Hydrogen generation from renewable biomass like glycerol could potentially serve as a sustainable energy source and could substantially help reduce the carbon footprint of the environment 
    more » « less
  4. ; ; ; ; ; ; ; ; ; ; et al (, ChemSusChem)
    Abstract High‐efficiency and low‐cost catalysts for oxygen evolution reaction (OER) are critical for electrochemical water splitting to generate hydrogen, which is a clean fuel for sustainable energy conversion and storage. Among the emerging OER catalysts, transition metal dichalcogenides have exhibited superior activity compared to commercial standards such as RuO2, but inferior stability due to uncontrolled restructuring with OER. In this study, we create bimetallic sulfide catalysts by adapting the atomic ratio of Ni and Co in CoxNi1‐xSyelectrocatalysts to investigate the intricate restructuring processes. Surface‐sensitive X‐ray photoelectron spectroscopy and bulk‐sensitive X‐ray absorption spectroscopy confirmed the favorable restructuring of transition metal sulfide material following OER processes. Our results indicate that a small amount of Ni substitution can reshape the Co local electronic structure, which regulates the restructuring process to optimize the balance between OER activity and stability. This work represents a significant advancement in the development of efficient and noble metal‐free OER electrocatalysts through a doping‐regulated restructuring approach. 
    more » « less
  5. ; ; ; (, Applied Physics Letters)
    We report a method of engineering a reversible change in interlayer bonding between layers of exfoliated thin films of MoS2 by means of hydrogen intercalation through forming gas annealing. Interlayer bonding strength is probed through the behavior of MoS2 under process-induced strain engineering, where two-dimensional (2D) flakes are encapsulated with a deposited stressed thin film layer to transfer strain into the underlying 2D materials. It is shown that after forming gas annealing, the depth of the strain transferred into multilayer MoS2 is enhanced as determined through layer-thickness-dependent Raman spectroscopic mapping. This change represents a transition from a 2D van der Waals-bonded material in the as-exfoliated samples to a more three-dimensional (3D)-bonded system in the annealed samples. We demonstrate the reversibility of this effect by means of vacuum annealing of previously forming gas annealed samples. The process of forming gas annealing itself also imparts strain into MoS2 due to a combination of 2D-to-3D bonding transition with differential thermal mismatch between the MoS2 and the substrate. These strains are shown to be retained after the vacuum annealing process, despite the transition back to 2D bonding. Since forming gas annealing is a common technical process in engineering 2D electronic devices, these results represent an important consideration in understanding non-intentionally applied strains due to changes in the mechanical properties of 2D materials. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email