Detail publikace

The unexpected photoelectrochemical activity of MAX phases: the role of oxide impurities

SANNA, M. NOVCIC, K. NG, S. ČERNÝ, M. PUMERA, M.

Originální název

The unexpected photoelectrochemical activity of MAX phases: the role of oxide impurities

Typ

článek v časopise ve Web of Science, Jimp

Jazyk

angličtina

Originální abstrakt

MAX phases are layered ternary compounds that are mainly studied for their physical properties and their use in the synthesis of MXenes. Their application in energy generation has been investigated and recently, the unexpected photoactivity of MAX phases under the influence of a visible light source has been reported. To investigate the origin of this photoactivity, theoretical calculations and experimental characterisation of the structural and optical properties of three MAX phases, Nb2AlC, Ta2AlC and Ti3AlC2, were performed. Although the theoretical calculations confirmed that the phases presented no band gap in the vicinity of the Fermi level, the experimental evaluation showed two main absorptions for Nb2AlC and Ta2AlC (2.2 eV, 3.1 eV, and 2.2 eV, 3.3 eV, respectively) and one for Ti3AlC2 (2.4 eV). To confirm the observations from the optical characterisation, the phases were applied as photoelectrocatalysts for hydrogen generation under the influence of light of different wavelengths. Nb2AlC and Ta2AlC performed better when exposed to UV light, while Ti3AlC2 showed the lowest overpotential under the influence of visible light, in accordance with the experimentally estimated band gaps. The materials were extensively characterised and the photoactivity of MAX phases was attributed to the presence of photoactive oxide impurities on the surface of the material, which are naturally formed from contact with air and solvents. In this work, we show how these impurities can lead to better performances thanks to their intrinsic photoactivity, indicating the prospects for the use of MAX phases in other photoelectrochemical processes.

Klíčová slova

SOLAR HYDROGEN-PRODUCTION; BAND-GAP; ELECTRONIC-STRUCTURE; OPTICAL-PROPERTIES; METAL IMPURITIES; TRANSITION; FILMS; SURFACE; EVOLUTION; TA2O5

Autoři

SANNA, M.; NOVCIC, K.; NG, S.; ČERNÝ, M.; PUMERA, M.

Vydáno

8. 2. 2023

Nakladatel

ROYAL SOC CHEMISTRY

Místo

CAMBRIDGE

ISSN

2050-7496

Periodikum

Journal of Materials Chemistry A

Ročník

11

Číslo

6

Stát

Spojené království Velké Británie a Severního Irska

Strany od

3080

Strany do

3090

Strany počet

11

URL

https://pubs.rsc.org/en/content/articlelanding/2023/TA/D2TA06929F

BibTex

@article{BUT184130,
  author="Michela {Sanna} and Katarina {Novcic} and Siow Woon {Ng} and Miroslav {Černý} and Martin {Pumera}",
  title="The unexpected photoelectrochemical activity of MAX phases: the role of oxide impurities",
  journal="Journal of Materials Chemistry A",
  year="2023",
  volume="11",
  number="6",
  pages="3080--3090",
  doi="10.1039/d2ta06929f",
  issn="2050-7496",
  url="https://pubs.rsc.org/en/content/articlelanding/2023/TA/D2TA06929F"
}