Issue 16, 2017

Action spectra in semiconductor photocatalysis

Abstract

Action spectra are an increasingly important part of semiconductor photocatalyst research, and comprise a plot of photonic efficiency, η, versus excitation wavelength, λ. The features and theory behind an ideal photocatalytic system are discussed, and used to identify: (i) the key aspect of an ideal action spectrum, namely: it is a plot of η vs. λ which has the same shape as that of the fraction of radiation absorbed by the semiconductor photocatalyst, f, versus λ and (ii) the key requirement when running an action spectrum, namely, that the initial rate of the photocatalytic process is directly proportional to incident photon flux, ρ, at wavelengths where η > 0. The Pt/TiO2/MeOH system is highlighted as an example of a photosystem that yields an ideal action spectrum. Most photocatalytic systems exhibit non-ideal action spectra, mostly due to one or more of the following: light intensity effects, crystal phase effects, dye-sensitisation, dye photolysis, charge transfer complex, CTC, formation and localized surface plasmon radiation, LSPR, absorption by a deposited noble metal catalyst. Each of these effects is illustrated using examples taken from the literatures and discussed. A suggested typical protocol for recording the action spectrum and absorption/diffuse reflectance spectrum of a photocatalytic system is described. The dangers of using a dye to probe the activity of a photocatalysts are also discussed, and a possible way to avoid this, via reductive photocatalysis, is suggested.

Graphical abstract: Action spectra in semiconductor photocatalysis

Article information

Article type
Tutorial Review
Submitted
21 Feb 2017
First published
30 Jun 2017

Chem. Soc. Rev., 2017,46, 4877-4894

Action spectra in semiconductor photocatalysis

S. Lee, A. Mills and C. O'Rourke, Chem. Soc. Rev., 2017, 46, 4877 DOI: 10.1039/C7CS00136C

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements