Molybdenum sulfide emerged as promising hydrogen evolution reaction (HER) electrocatalyst thanks to its high intrinsic activity, however its limited active sites exposure and low conductivity hamper its performance. To address these drawbacks, the non‐equilibrium nature of pulsed laser deposition (PLD) is exploited to synthesize self‐supported hierarchical nanoarchitectures by gas phase nucleation and sequential attachment of defective molybdenum sulfide clusters. The physics of the process are studied by in situ diagnostics and correlated to the properties of the resulting electrocatalyst. The as‐synthesized architectures have a disordered nanocrystalline structure, with nanodomains of bent, defective S‐Mo‐S layers embedded in an amorphous matrix, with excess sulfur and segregated molybdenum particles. Oxygen incorporation in this structure fosters the creation of amorphous oxide/oxysulfide nanophases with high electrical conductivity, enabling fast electron transfer to the active sites. The combined effect of the nanocrystalline pristine structure and the surface oxidation enhances the performance leading to small overpotentials, very fast kinetics (35.1 mV dec−1 Tafel slope) and remarkable long‐term stability for continuous operation up to ‐1 A cm−2. This work shows possible new avenues in catalytic design arising from a non‐equilibrium technique as PLD and the importance of structural and chemical control to improve the HER performance of MoS‐based catalysts.

Non‐Equilibrium Synthesis of Highly Active Nanostructured, Oxygen‐Incorporated Amorphous Molybdenum Sulfide HER Electrocatalyst / Giuffredi, Giorgio; Mezzetti, Alessandro; Perego, Andrea; Mazzolini, Piero; Prato, Mirko; Fumagalli, Francesco; Lin, Yu‐chuan; Liu, Chenze; Ivanov, Ilia N.; Belianinov, Alex; Colombo, Massimo; Divitini, Giorgio; Ducati, Caterina; Duscher, Gerd; Puretzky, Alexander A.; Geohegan, David B.; Di Fonzo, Fabio. - In: SMALL. - ISSN 1613-6810. - (2020), p. 2004047. [10.1002/smll.202004047]

Non‐Equilibrium Synthesis of Highly Active Nanostructured, Oxygen‐Incorporated Amorphous Molybdenum Sulfide HER Electrocatalyst

Mazzolini, Piero;Colombo, Massimo;
2020-01-01

Abstract

Molybdenum sulfide emerged as promising hydrogen evolution reaction (HER) electrocatalyst thanks to its high intrinsic activity, however its limited active sites exposure and low conductivity hamper its performance. To address these drawbacks, the non‐equilibrium nature of pulsed laser deposition (PLD) is exploited to synthesize self‐supported hierarchical nanoarchitectures by gas phase nucleation and sequential attachment of defective molybdenum sulfide clusters. The physics of the process are studied by in situ diagnostics and correlated to the properties of the resulting electrocatalyst. The as‐synthesized architectures have a disordered nanocrystalline structure, with nanodomains of bent, defective S‐Mo‐S layers embedded in an amorphous matrix, with excess sulfur and segregated molybdenum particles. Oxygen incorporation in this structure fosters the creation of amorphous oxide/oxysulfide nanophases with high electrical conductivity, enabling fast electron transfer to the active sites. The combined effect of the nanocrystalline pristine structure and the surface oxidation enhances the performance leading to small overpotentials, very fast kinetics (35.1 mV dec−1 Tafel slope) and remarkable long‐term stability for continuous operation up to ‐1 A cm−2. This work shows possible new avenues in catalytic design arising from a non‐equilibrium technique as PLD and the importance of structural and chemical control to improve the HER performance of MoS‐based catalysts.
2020
Non‐Equilibrium Synthesis of Highly Active Nanostructured, Oxygen‐Incorporated Amorphous Molybdenum Sulfide HER Electrocatalyst / Giuffredi, Giorgio; Mezzetti, Alessandro; Perego, Andrea; Mazzolini, Piero; Prato, Mirko; Fumagalli, Francesco; Lin, Yu‐chuan; Liu, Chenze; Ivanov, Ilia N.; Belianinov, Alex; Colombo, Massimo; Divitini, Giorgio; Ducati, Caterina; Duscher, Gerd; Puretzky, Alexander A.; Geohegan, David B.; Di Fonzo, Fabio. - In: SMALL. - ISSN 1613-6810. - (2020), p. 2004047. [10.1002/smll.202004047]
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11381/2880838
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 27
  • ???jsp.display-item.citation.isi??? 27
social impact