Assessing the photocatalytic oxygen evolution reaction of BiFeO₃ loaded with IrO₂ nanoparticles as cocatalyst

authored by

Wegdan Ramadan, Armin Feldhoff, Detlef Bahnemann

Abstract

Oxygen evolution is kinetically the key step in the photocatalytic water splitting, but it is negatively affected by the poor charge transport properties. However, this can be modified by the loading of cocatalysts on the surface of a semiconductor which could form heterojunctions to boost the charge separation and lower the activation potential for O

₂ evolution. In this paper we demonstrate that the poor O

₂ evolution activity of photocatalytic water splitting of the multiferroics BiFeO

₃ can be enhanced when a proper cocatalyst like IrO

₂ nanoparticles are deposited on the surface and proper electron scavenger is used. The choice of the persulfate, S

₂O

₈ as electron scavenger is influenced by its high redox potential and its close position to the valence band of BiFeO

₃ compared to other commonly used scavengers. Another interesting information was revealed by using transient absorption spectroscopy under different environment namely, inert, oxidizing and reducing. The absorption peak of holes was identified and correlated to the strong absorption around 560 nm The hole absorption peak showed a 50% decrease in the absorption intensity after 2.5 μsec indicating that holes are captured by IrO

₂ nanoparticles on the surface. O

₂ evolution of multiferroics, especially BiFeO

₃ has been less investigated. Therefore, the development of efficient photocatalytic materials has relied on both photocatalysts and cocatalysts. Identification of the photogenerated charge absorption peak from transient absorption spectra facilitate the evaluation of the IrO

₂ loading effect on the charge separation and the overall O

₂ evolution process.

Organisation(s)

Institute of Physical Chemistry and Electrochemistry
Institute of Technical Chemistry
Laboratory of Nano and Quantum Engineering

External Organisation(s)

Alexandria University
Saint Petersburg State University

Type

Article

Journal

Solar Energy Materials and Solar Cells

Volume

232

ISSN

0927-0248

Publication date

10.2021

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials, Surfaces, Coatings and Films, Renewable Energy, Sustainability and the Environment

Sustainable Development Goals

SDG 7 - Affordable and Clean Energy

Electronic version(s)

https://doi.org/10.1016/j.solmat.2021.111349 (Access: Closed)