In Situ Study of Graphene Oxide Quantum Dot-MoSx Nanohybrids as Hydrogen Evolution Catalysts

Surfaces

Laura Calvillo¹  Mattia Cattelan¹  Marco Favaro¹  Gaetano Granozzi¹  Stefano Agnoli¹  StephenW. T. Price²  AndreaE. Russell³ 

[1] Dipartimento di Scienze Chimiche, Università di Padova, Via Marzolo 1, 35131 Padova, Italy;Finden Ltd., 1.12 Building R71, Harwell Campus, Oxfordshire OX11 0QZ, UK;School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, UK;

关键词: in line XPS-electrochemistry;    operando XAS;    HER;   

DOI  :  10.3390/surfaces3020017

来源: DOAJ

【 摘 要 】

Graphene quantum dots (GOQDs)-MoS_x nanohybrids with different MoS_x stoichiometries (x = 2 and 3) were prepared in order to investigate their chemical stability under hydrogen evolution reaction (HER) conditions. Combined photoemission/electrochemical (XPS/EC) measurements and operando X-ray absorption spectroscopy (XAS) were employed to determine the chemical changes induced on the MoS_x-based materials as a function of the applied potential. This in situ characterization indicates that both MoS₂ and MoS₃ materials are stable under operating conditions, although sulfur terminal sites in the MoS₃ nanoparticles are converted from S-dimer (S₂²⁻) to S-monomer (S²⁻), which constitute the first sites where the hydrogen atoms are adsorbed for their subsequent evolution. In order to complete the characterization of the GOQDs-MoS_x nanohybrids, the composition and particle size were determined by X-ray photoemission spectroscopy (XPS), X-ray diffraction (XRD) and Raman spectroscopy; whereas the HER activity was studied by conventional electrochemical techniques.

【 授权许可】

Unknown