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Comparative assessment of visible light and UV active photocatalysts by hydroxyl radical quantification.

Nagarajan, Sanjay; Skillen, Nathan C.; Fina, Federica; Zhang, Guan; Randorn, Chamnan; Lawton, Linda A.; Irvine, John T.S.; Robertson, Peter K.J.


Sanjay Nagarajan

Nathan C. Skillen

Federica Fina

Guan Zhang

Chamnan Randorn

John T.S. Irvine

Peter K.J. Robertson


A simple method for determining hydroxyl radical yields on semiconductor photocatalysts is highly desirable, especially when comparing different photocatalyst materials. This paper reports the screening of a selection of visible light active photocatalysts such as Pt-C3N4, 5% LaCr doped SrTiO3, Sr0.95Cr0.05TiO3 and Yellow TiO2 and compares them against WO3 and ultra violet (UV) light activated TiO2 P25 (standard commercial catalysts) based on their oxidative strengths (OH radical producing capability) using a well-studied chemical probe–coumarin. 7-hydroxycoumarin, the only fluorescent hydroxylation product of this reaction can then be measured to indirectly quantify the OH radicals produced. P25 under UV light produced the highest concentration of OH radicals (16.9μM), followed by WO3 (0.56μM) and Pt-C3N4 (0.25μM). The maximum OH radical production rate for P25, WO3 and Pt-C3N4 were also determined and found to be 35.6μM/hr, 0.28μM/h and 0.88μM/h respectively. The other visible light activated photocatalysts did not produce any OH radicals primarily as a result of their electronic structure. Furthermore, it was concluded that, if any visible light absorbing photocatalysts are to be fabricated in future for the purpose of photocatalytic oxidation, their OH radical producing rates (and quantities) should be determined and compared to P25.


NAGARAJAN, S., SKILLEN, N.C., FINA, F., ZHANG, G., RANDORN, C., LAWTON, L.A., IRVINE, J.T.S. and ROBERTSON, P.K.J. 2016. Comparative assessment of visible light and UV active photocatalysts by hydroxyl radical quantification. Journal of photochemistry and photobiology A: chemistry [online], 334, pages 13-19. Available from:

Journal Article Type Article
Acceptance Date Oct 27, 2016
Online Publication Date Nov 3, 2016
Publication Date Feb 1, 2017
Deposit Date Nov 23, 2016
Publicly Available Date Nov 4, 2017
Journal Journal of photochemistry and photobiology A: chemistry
Print ISSN 1010-6030
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 334
Pages 13-19
Keywords Photocatalyst; Visible light photocatalysts; OH radical; Coumarin; P25
Public URL


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