Shahraei, Ali ; Moradabadi, Ashkan ; Martinaiou, Ioanna ; Lauterbach, Stefan ; Klemenz, Sebastian ; Dolique, Stephanie ; Kleebe, Hans-Joachim ; Kaghazchi, Payam ; Kramm, Ulrike I. (2017)
Elucidating the Origin of Hydrogen Evolution Reaction Activity in Mono- and Bimetallic Metal- and Nitrogen-Doped Carbon Catalysts (Me–N–C).
In: ACS Applied Materials & Interfaces, 9 (30)
doi: 10.1021/acsami.7b01647
Artikel, Bibliographie

Kurzbeschreibung (Abstract)

In this work, we present a comprehensive study on the role of metal species in MOF-based Me-N-C (mono and bimetallic) catalysts for the hydrogen evolution reaction (HER). The catalysts are investigated with respect to HER activity and stability in alkaline electrolyte. Based on structural analysis by X-ray diffraction, X-ray induced photoelectron spectroscopy and Transition electron microscopy it is concluded that MeN4 sites seem to dominate the HER activity of these catalysts. There is a strong relation between the amount of MeN4 sites that is formed and the energy of formation related to these sites integrated at the edge of a graphene layer, as obtained from DFT calculations. Our results show, for the first time, that the combination of two metals (Co and Mo) in a bimetallic (Co,Mo)-N-C catalyst allows hydrogen production with a significantly improved overpotential in comparison to its monometallic counterparts and other Me-N-C catalysts. By the combination of experimental result with DFT calculations. we show that the origin of the enhanced performance of our (Co, Mo)-N-C catalyst seems to be provided by an improved hydrogen binding energy (HBE) on one MeN4 site due to the presence of a second MeN4 site in its close vicinity, as investigated in detail for our most active (Co,Mo)-N-C catalyst. The outstanding stability and good activity make especially the bimetallic Me-N-C catalysts interesting candidates for solar fuel applications.

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