Deciphering electrochemiluminescence generation from luminol and hydrogen peroxide by imaging light emitting layer  

作　　者：Ping Zhou Shujie Hu Weiliang Guo Bin Su 

机构地区：[1]Institute of Analytical Chemistry,Department of Chemistry,Zhejiang University,Hangzhou 310058,China [2]School of Chemistry and Materials Science,Nanjing Normal University,Nanjing 210023,China

出　　处：《Fundamental Research》2022年第5期682-687,共6页自然科学基础研究（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(Grants No.22125405 and 21874117);the Natural Science Foundation of Zhejiang Province(Grant No.LZ18B050001).

摘　　要：Electrochemiluminescence(ECL)of luminol is a luminescence process that proceeds in the presence of reactive oxygen species(e.g.hydrogen peroxide(H_(2)O_(2)))at a suitable electrode potential,the reaction mechanism of which is complicated and remains ambiguous.In this work,we report a visualization approach for measuring the thickness of the ECL layer(TEL)of the luminol/H_(2)O_(2) system to decipher the reaction process by combined use of the microtube electrode,ECL microscopy,and finite element simulations.With the increase of solution pH,the ECL image captured with the microtube electrode tends to vary from spot to ring,corresponding to the decrease of TEL from>9.1𝜇m to ca.4.3𝜇m.We propose that different intermediates are involved in the course of ECL reaction.At a low pH(e.g.pH<9),a relatively large TEL is most likely determined by the diffusion of oxidized and deprotonated luminol intermediate that is neutral and has a long lifetime.While at a high pH(e.g.pH in the range of 10 to 12),the ECL reaction is controlled by short-lived radical intermediates of both luminol and superoxide anion.The proposed mechanism is proved theoretically by finite element simulations and experimentally by the apparent effect of concentration ratio of luminol/H_(2)O_(2).

关 键 词：LUMINOL Hydrogen peroxide Electrochemiluminescence layer Microtube electrode ECL microscopy Reaction mechanism 

分 类 号：O646[理学—物理化学]