Revisiting the Active Sites at the MoS 2 /H 2 O Interface via Grand-Canonical DFT: The Role of Water Dissociation - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue ACS Applied Materials & Interfaces Année : 2020

Revisiting the Active Sites at the MoS 2 /H 2 O Interface via Grand-Canonical DFT: The Role of Water Dissociation

Résumé

MoS 2 is a promising low-cost catalyst for the hydrogen evolution reaction (HER). However, the nature of the active sites remains debated. By taking the electrochemical potential explicitly into account using grand-canonical density functional theory (DFT) in combination with the linearized Poisson-Boltzmann equation, we herein revisit the active sites of 2H-MoS 2. In addition to the well-known catalytically active edge sites, also specific point-defects on the otherwise inert basal plane provide highly active sites for HER. Given that HER takes place in water, we also assess the reactivity of these active sites with respect to H 2 O. The thermodynamics of proton reduction as a function of the electrochemical potential reveals that four edge sites and three basal plane defects feature thermodynamic over-potentials below 0.2 V. In contrast to current proposals, many of these active sites involve adsorbed OH. The results demonstrate that even though H 2 O and OH block "active" sites, HER can also occur on these "blocked" sites, 1 reducing protons on surface OH/H 2 O entities. As a consequence, our results revise the active sites, highlighting the so far overlooked need to take the liquid component (H 2 O) of the functional interface into account when considering the stability and activity of the various active sites.
Fichier principal
Vignette du fichier
main.pdf (2.86 Mo) Télécharger le fichier
Revisiting SI.pdf (3.14 Mo) Télécharger le fichier
am0c06489_si_002.zip (165.79 Ko) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)

Dates et versions

hal-02917736 , version 1 (19-08-2020)

Identifiants

Citer

Nawras Abidi, Audrey Bonduelle-Skrzypczak, Stephan N. Steinmann. Revisiting the Active Sites at the MoS 2 /H 2 O Interface via Grand-Canonical DFT: The Role of Water Dissociation. ACS Applied Materials & Interfaces, 2020, 12 (28), pp.31401-31410. ⟨10.1021/acsami.0c06489⟩. ⟨hal-02917736⟩
113 Consultations
373 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More