{"term":{"id":"14041","title":"photocatalytic active centre","longtitle":"IUPAC Gold Book - photocatalytic active centre","doi":"10.1351\/goldbook.14041","code":"14041","status":"current","definitions":[{"id":1,"text":"Surface centre, i.e., either a surface defect or a regular surface site, at which a chemical transformation takes place after converting the centre into an active state by a photophysical process, e.g., by photoexcitation.","notes":{"1":"The number of photoactive centres is very often difficult to establish, particularly on solid surfaces and in suspended particles.","2":"When the density of the active centres is unknown, the reaction rates may be related to the \\(\\rm{BET}(\\ce{N2})\\) area with the understanding that the parameter or property of the system will be a lower limit of the actual value, because the surface determined by \\(\\ce{N2}\\) adsorption will be larger than that reached by the radiation. See Note 2 under the definition of Brunauer–Emmett–Teller (BET) surface area.","3":"The photophysical process may include one or several processes such as direct excitation of the photocatalytic centre via absorption of ultraviolet, visible, or infrared radiation, via photocarrier trapping, via interaction with excitons, or via energy and\/or electron transfer from a photoexcited reagent or intermediate."},"links":[{"term":"Brunauer–Emmett–Teller (BET) surface area","url":"https:\/\/goldbook.iupac.org\/\/terms\/view\/13997"},{"term":"catalytic site","url":"https:\/\/goldbook.iupac.org\/\/terms\/view\/13999"},{"term":"photocarrier","url":"https:\/\/goldbook.iupac.org\/\/terms\/view\/14040"}],"sources":["PAC, 2011, 83, 931. 'Glossary of terms used in photocatalysis and radiation catalysis (IUPAC Recommendations 2011)' on page 967 (https:\/\/doi.org\/10.1351\/PAC-REC-09-09-36)"]}],"altoutputs":{"html":"https:\/\/goldbook.iupac.org\/terms\/view\/14041\/html","xml":"https:\/\/goldbook.iupac.org\/terms\/view\/14041\/xml","plain":"https:\/\/goldbook.iupac.org\/terms\/view\/14041\/plain"},"citation":"Citation: 'photocatalytic active centre' 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.14041","license":"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.","collection":"If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org .","disclaimer":"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.","accessed":"2026-06-21T16:01:05+00:00"}}