Molybdenum Disulfide As a Protection Layer and Catalyst for Gallium Indium Phosphide Solar Water Splitting Photocathodes

Britto, Reuben J; Benck, Jesse D.; Young, James L.; Hahn, Christopher; Deutsch, Todd G.; Jaramillo, Thomas F.

doi:10.1149/ma2016-02/49/3724

Cited by 7 publications

(20 citation statements)

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“…The organic moieties of functionalized MoS 2 were characterized using attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) and solid-state 13 C cross-polarization magic-angle spinning nuclear magnetic resonance spectroscopy ( 13 C CPMAS NMR). The coverages were quantified by fitting the multiple peaks in the sulfur 2p high-resolution X-ray photoelectron spectra (XPS) with the peaks at ∼162.4 eV binding energy assigned to sulfur bound to carbon (S−C).…”

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confidence: 99%

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Reductant-Activated, High-Coverage, Covalent Functionalization of 1T′-MoS₂

Yan

Cabán-Acevedo

Papadantonakis

et al. 2019

ACS Materials Lett.

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Recently developed covalent functionalization chemistry for MoS2 in the 1Tʹ phase enables the formation of covalent chalcogenide-carbon bonds from alkyl halides and aryl diazonium salts. However, the coverage of functional groups using this method has been limited by the negative charge stored in the exfoliated MoS2 sheets to <25-30% per MoS2 unit. We report herein a reductantactivated functionalization wherein one-electron metallocene reductants, such as nickelocene, octamethylnickelocene, and cobaltocene, are introduced during functionalization with methyl and propyl halides to tune the coverage of the alkyl groups. The reductant-activated functionalization yields functional group coverages up to 70%, ~ 1.5-2 times higher than the previous limit, and enables functionalization by weak electrophiles, such as 1-chloropropane, that are otherwise unreactive with chemically exfoliated MoS2. We also explored the dependence of coverage on the strength of the leaving group and the steric hindrance of the alkyl halide in the absence of reductants, and showed that functionalization was ineffective for chloride leaving groups and for secondary and tertiary alkyl iodides. These results demonstrate a substantial increase in coverage compared to functionalization without reductants, and may impact the performance of these materials in applications reliant on surface interactions. Furthermore, this method may be applicable to the covalent functionalization of similar layered materials and metal chalcogenides.

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“…Figure 2 shows the XPS, ATR-FTIR, and 13 C CPMAS NMR for ceMoS 2 before and after functionalization by iodomethane (methyl-MoS 2 ), 1-iodopropane (propyl-MoS 2 ), 1-bromopropane (propyl-MoS 2 ), and 1-chloropropane. This set of reagents was chosen to explore the dependence of reactivity on the leaving group.…”

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confidence: 99%

Reductant-Activated, High-Coverage, Covalent Functionalization of 1T′-MoS₂

Yan

Cabán-Acevedo

Papadantonakis

et al. 2019

ACS Materials Lett.

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“…31,34,50,52,53 These disordered MoS 2 /MoS x materials can exhibit exchange current densities upward of 10 −5 A cm −2 , compared to 10 −4 A cm −2 for Pt. 32,54 The onset potential for hydrogen evolution of MoS x thin films deposited for 30 s in this work (0.68 and 0.62 V at 0.1 mA cm −2 ) surpasses other MoS 2/x films on p-GaInP 2 photocathodes (0.36 16 and ∼0.49 2 V at 0.1 mA cm −2 ). Accordingly, these results suggest that the photoelectrodeposition process employed here also naturally yields a very active form of MoS x .…”

Section: ■ Discussionmentioning

confidence: 60%

“…A two-step Mo sputtering and the subsequent sulfidization process has been reported previously for modifying p-GaInP 2 that indicated it is difficult to fully convert Mo 0 films, especially at the interface. 16 Although the substoichiometry of the metal sulfide (and presence of Mo 0 ) apparently had minimal impact on the stability and catalytic activity of the electrode interface, the light-limited photocurrent was attenuated. This may signify an inherent limitation to the sulfidization process.…”

Section: ■ Discussionmentioning

confidence: 99%

“…More recently, a dual catalyst/protective layer design was employed during the deposition of MoS 2 on p-GaInP 2 . 16 A two-step method of sputtering Mo followed by sulfidization produced an active layer that improved the stability and was more electrocatalytic toward hydrogen evolution. Nevertheless, limited control of the sulfidization process led to unconverted elemental Mo that significantly decreased the observed photocurrent.…”

Section: ■ Introductionmentioning

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Protection of GaInP₂ Photocathodes by Direct Photoelectrodeposition of MoS_x Thin Films

Lancaster¹,

Mow

Liu

et al. 2019

ACS Appl. Mater. Interfaces

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Catalytic MoS x thin films have been directly photoelectrodeposited on GaInP2 photocathodes for stable photoelectrochemical hydrogen generation. Specifically, the MoS x deposition conditions were controlled to obtain 8–10 nm films directly on p-GaInP2 substrates without ancillary protective layers. The films were nominally composed of MoS2, with additional MoO x S y and MoO3 species detected and showed no long-range crystalline order. The as-deposited material showed excellent catalytic activity toward the hydrogen evolution reaction relative to bare p-GaInP2. Notably, no appreciable photocurrent reduction was incurred by the addition of the photoelectrodeposited MoS x catalyst to the GaInP2 photocathode under light-limited operating conditions, highlighting the advantageous optical properties of the film. The MoS x catalyst also imparted enhanced durability toward photoelectrochemical hydrogen evolution in acidic conditions, maintaining nearly 85% of the initial photocurrent after 50 h of electrolysis. In total, this work demonstrates a simple method for producing dual-function catalyst/protective layers directly on high-performance, planar III–V photoelectrodes for photoelectrochemical energy conversion.

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Stability and Performance of Sulfide-, Nitride-, and Phosphide-Based Electrodes for Photocatalytic Solar Water Splitting

Wei

Vayssières

2017

J. Phys. Chem. Lett.

102

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With the past decade of worldwide sustained efforts on artificial photosynthesis for photocatalytic solar water splitting and clean hydrogen generation by dedicated researchers and engineers from different disciplines, substantial progress has been achieved in raising its overall efficiency along with finding new photocatalysts. Various materials, systems, devices, and better fundamental understandings of the interplay between interfacial chemistry, electronic structure, and photogenerated charge dynamics involved have been developed. Nevertheless, the overall photocatalytic performance is yet to achieve its maximum theoretical limit. Moreover, the stability of well-known semiconductors (as well as novel ones) remains the biggest challenge that scientists are facing to develop durable industrial-scale devices for large-scale water oxidation and overall solar water splitting. In this Perspective, we summarize the major achievements and the different approaches carried out to improve the stability and performance of photoelectrodes based on sulfide, nitride, and phosphide semiconductors.

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Molybdenum Disulfide As a Protection Layer and Catalyst for Gallium Indium Phosphide Solar Water Splitting Photocathodes

Cited by 7 publications

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Reductant-Activated, High-Coverage, Covalent Functionalization of 1T′-MoS₂

Reductant-Activated, High-Coverage, Covalent Functionalization of 1T′-MoS₂

Protection of GaInP₂ Photocathodes by Direct Photoelectrodeposition of MoS_x Thin Films

Stability and Performance of Sulfide-, Nitride-, and Phosphide-Based Electrodes for Photocatalytic Solar Water Splitting

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Molybdenum Disulfide As a Protection Layer and Catalyst for Gallium Indium Phosphide Solar Water Splitting Photocathodes

Cited by 7 publications

References 0 publications

Reductant-Activated, High-Coverage, Covalent Functionalization of 1T′-MoS2

Reductant-Activated, High-Coverage, Covalent Functionalization of 1T′-MoS2

Protection of GaInP2 Photocathodes by Direct Photoelectrodeposition of MoSx Thin Films

Stability and Performance of Sulfide-, Nitride-, and Phosphide-Based Electrodes for Photocatalytic Solar Water Splitting

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Reductant-Activated, High-Coverage, Covalent Functionalization of 1T′-MoS₂

Reductant-Activated, High-Coverage, Covalent Functionalization of 1T′-MoS₂

Protection of GaInP₂ Photocathodes by Direct Photoelectrodeposition of MoS_x Thin Films