News & Notices

Organizations & People

Standing Committees

Divisions

Projects

Reports
..By Year
..By Division
..Other Committees
..Provisionals

Publications

Symposia

AMP

Links of Interest

Search the Site

Home Page

Pure Appl. Chem., Vol. 71, No. 2, pp.321-335, 1999

ORGANIC CHEMISTRY DIVISION

COMMISSION ON PHOTOCHEMISTRY

Terminology, relative photonic efficiencies and quantum yields in heterogeneous photocatalysis. Part II: Experimental determination of quantum yields

(Technical report)

Angela Salinaro, Alexei V. Emeline, Jincai Zhao, Hisao Hidaka, Vladimir K. Ryabchuk, and Nick Serpone.

Abstract: In the preceding article [Serpone and Salinaro, Pure Appl. Chem., 71(2), 303-320 (1999)] we examined two principal features of heterogeneous photocatalysis that demanded scrutiny: (i) description of photocatalysis and (ii) description of process efficiencies. For the latter we proposed a protocol relative photonic efficiency which could subsequently be converted to quantum yields. A difficulty in expressing a quantum yield in heterogeneous photochemistry is the very nature of the system, either solid/liquid or solid/gas, which places severe restrictions on measurement of the photon flow absorbed by the light harvesting component, herein the photocatalyst TiO2, owing to non-negligible scattering by the particulates. It was imperative therefore to examine the extent of this problem. Extinction and absorption spectra of TiO₂ dispersions were determined at low titania loadings by normal absorption spectroscopy and by an integrated sphere method, respectively, to assess the extent of light scattering. The method is compared to the one reported by Grela et al. [J. Phys. Chem., 100, 16940 (1996)] who used a polynomial extrapolation of the light scattered in the visible region into the UV region where TiO₂ absorbs significantly. This extrapolation underestimates the scattering component present in the extinction spectra, and will no doubt affect the accuracy of the quantum yield data. Further, we report additional details in assessing limiting photonic efficiencies and quantum yields in heterogeneous photocatalysis.

Full Text (744k pdf)

Page last modified 14 May 2000.
Copyright ©1997-2000 International Union of Pure and Applied Chemistry.
Questions or comments about IUPAC, please contact, the Secretariat.
Questions regarding the website, please contact Web Help.