14044 IUPAC Gold Book - photocatalytic efficiency 10.1351/goldbook.14044 14044 current 1 Number of entities (product) formed (alternatively the number of reactant entities disappearing) divided by the number of ultraviolet, visible, or infrared photons incident (prior to absorption) on the system and in a wavelength range \(\lambda_{1}{-}\lambda_{2}\). Quantity relevant in applications of photocatalysis where the interest is to assess an engineering efficiency of energy out vs. energy in. In this context, the quantity has a well-defined meaning only when the operating conditions are also stated and results reported in terms of the initial conditions. When using photon flux (number basis or chemical amount basis) the term photonic efficiency is preferred, as efficiency refers to excitation within a wavelength range, whereas for monochromatic irradiation (and incident photons) the term photonic yield should be used. photonic efficiency https://goldbook.iupac.org//terms/view/14057 photonic yield https://goldbook.iupac.org//terms/view/14058 PAC, 2011, 83, 931. 'Glossary of terms used in photocatalysis and radiation catalysis (IUPAC Recommendations 2011)' on page 968 (https://doi.org/10.1351/PAC-REC-09-09-36) https://goldbook.iupac.org/terms/view/14044/html https://goldbook.iupac.org/terms/view/14044/json https://goldbook.iupac.org/terms/view/14044/plain Citation: 'photocatalytic efficiency' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.14044 The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms. If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org . The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using. 2026-05-07T00:06:33+00:00