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

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216305%3A26620%2F23%3APU148611" target="_blank" >RIV/00216305:26620/23:PU148611 - isvavai.cz</a>

Alternative codes found

RIV/61989100:27240/23:10252924

Result on the web

<a href="https://pubs.rsc.org/en/content/articlelanding/2023/TA/D2TA06929F" target="_blank" >https://pubs.rsc.org/en/content/articlelanding/2023/TA/D2TA06929F</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1039/d2ta06929f" target="_blank" >10.1039/d2ta06929f</a>

Result language

angličtina

Original language name

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

Original language description

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.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10400 - Chemical sciences

Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2023

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Journal of Materials Chemistry A

ISSN

2050-7488

e-ISSN

2050-7496

Volume of the periodical

11

Issue of the periodical within the volume

6

Country of publishing house

GB - UNITED KINGDOM

Number of pages

11

Pages from-to

3080-3090

UT code for WoS article

000920422600001

EID of the result in the Scopus database

2-s2.0-85147339106