uu.seUppsala universitets publikasjoner
Endre søk
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Impedance Spectroscopy Modeling of Nickel–Molybdenum Alloys on Porous and Flat Substrates for Applications in Water Splitting
Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.ORCID-id: 0000-0002-8279-5163
Vise andre og tillknytning
2019 (engelsk)Inngår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455Artikkel i tidsskrift (Fagfellevurdert) Epub ahead of print
Abstract [en]

Hydrogen production by splitting water using electrocatalysts powered by renewable energy from solar or wind plants is one promising alternative to produce a carbon–freeand sustainable fuel. Earth–abundant and non–precious metals are here of interest as a replacement for scarce and expensive platinum group catalysts. Ni–Mo is a promising alternative to Pt but the type of substrate could ultimately affect both the initial growth conditions as well as the final charge transfer in the system as a whole with resistive junctions formed in the heterojunction interface. In this study, we investigated the effect of different substrates on the hydrogen evolution reaction (HER) of Ni–M oelectrocatalysts. Ni–Mo catalysts (30 at. % Ni, 70 at. % Mo) were sputtered on various substrates with different porosity and conductivity. There was no apparent morphological difference at the surface of the catalytic films sputtered on the different substrates, and the substrates were classified from microporous to flat. The electrochemical characterization was carried out with linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) in the frequency range 0.7 Hz–100 kHz. LSV measurements were carried out at DC potentials between 200 and –400 mV vs. the reversible hydrogen electrode (RHE) in 1 M NaOH encompassing the HER. The lowest overpotentials for HER were obtained for films on nickel foam at all current densities (–157 mV vs. RHE @ 10 mA cm-2), and the overpotentials increased in the order of nickel foil, carbon cloth, fluorine doped tin oxide and indium tin oxide glass, respectively. EIS data were fitted with two equivalent circuit models and compared for different DC potentials and different substrate morphologies and conductivities. By critical evaluation of the data from the models, the influence of the substrates on the reaction kinetics was seen in the high– and low–frequency region. In the high–frequency region, a strong substrate dependence was seen and interpreted with a Schottky–type barrier, which can be rationalized as being due to a potential barrier in the material heterojunctions or a resistive substrate–film oxide/hydroxide. The results highlight the importance of substrates, the total charge transfer properties in electrocatalysis, the relevance of different circuit components in EIS as well as underpin the necessity to incorporate high conductivity, chemically inert and work function matched substrate–catalysts in the catalyst system.

sted, utgiver, år, opplag, sider
American Chemical Society (ACS), 2019.
HSV kategori
Forskningsprogram
Teknisk fysik med inriktning mot fasta tillståndets fysik
Identifikatorer
URN: urn:nbn:se:uu:diva-395176OAI: oai:DiVA.org:uu-395176DiVA, id: diva2:1360848
Tilgjengelig fra: 2019-10-14 Laget: 2019-10-14 Sist oppdatert: 2019-10-14

Open Access i DiVA

Fulltekst mangler i DiVA

Søk i DiVA

Av forfatter/redaktør
Niklasson, Gunnar A.
Av organisasjonen
I samme tidsskrift
The Journal of Physical Chemistry C

Søk utenfor DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric

urn-nbn
Totalt: 9 treff
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf