Elucidating Electrocatalytic Oxygen Reduction Kinetics via Intermediates by Time‐Dependent Electrochemiluminescence

Abstract

Facile evaluation of oxygen reduction reaction (ORR) kinetics for massive electrocatalysts is critical for sustainable fuel cells development and industrial H2O2 production. Despite great success in ORR studies by mainstream strategies, such as membrane electrode assembly, rotation electrode technique and advanced surfacesensitive spectroscopy, the time/spatial distribution of reactive oxygen species (ROS) intermediates in the diffusion layer is still unknown. By time-dependent electrochemiluminescence (Td-ECL), here we report an intermediate-oriented methodology for ORR kinetics analysis. Thanks to multiple ultra-sensitive stoichiometric reactions between ROS and the ECL emitter, except for electron transfer numbers and rate constants, the potential-dependent time/spatial distribution of ROS was successfully obtained for the first time. Such uncovered exclusive information would guide fuel cells and H2O2 production with maximized activity and durability, for instance, a larger overpotential would be beneficial to electrocatalysts of 2e − reduction for H2O2 production, because of the high yield of H2O2 and low concentration of attackable O2 •− . This work would pave the exploration of not only the fundamentals of unambiguous ORR mechanism but also the durability of electrocatalysts for practical applications.

CRISPR/Cas12a-Mediated Aptasensor Based on Tris-(8-hydroxyquinoline)aluminum Microcrystals with Crystallization-Induced Enhanced Electrochemiluminescence for Acetamiprid Analysis

“…For example, Hou et al adopted transparent polymeric carbon nitride films with exceptionally improved ECL efficiency as luminophores to construct a visual biosensor for highly sensitive DNA detection . Wu et al utilized time-dependent ECL to develop an intermediate-oriented strategy for evaluating the kinetics of ORR electrocatalysts . Undoubtedly, ECL technology has become an ideal option for ACE analysis.…”

Bioinspired Single‐Atom Sites Enable Efficient Oxygen Activation for Switching Anodic/Cathodic Electrochemiluminescence

“…Assisted by the ORR‐induced reactive oxygen species (ROS), such as superoxide radicals (O 2 ⋅ − ), hydroxyl radical (⋅OH), and singlet oxygen ( 1 O 2 ), the efficiency of anodic luminescence has been significantly improved. Note that some catalysts have been found to directly trigger the cathodic ECL, which not only overcomes the dependence of anodic electrochemical oxidation but also achieves efficient utilization of active intermediates generated at the cathode [8–10] . It should be pointed out that the effect of ROS type on luminescence properties has not been fully elucidated because of the low catalytic selectivity for O 2 activation and the multiple ROS involved in the ORR process [11, 12] .…”

“…Note that some catalysts have been found to directly trigger the cathodic ECL, which not only overcomes the dependence of anodic electrochemical oxidation but also achieves efficient utilization of active intermediates generated at the cathode. [8][9][10] It should be pointed out that the effect of ROS type on luminescence properties has not been fully elucidated because of the low catalytic selectivity for O 2 activation and the multiple ROS involved in the ORR process. [11,12] In this regard, tuning catalysts and achieving selective catalytic activation of O 2 is highly desirable to regulate ECL properties and to gain further insight into the relationship between the active intermediates and luminescent properties.…”

Photoinduced Electrogenerated Chemiluminescence Imaging of Plasmonic Photoelectrochemistry at Single Nanocatalysts

“…For example, as luminol chemiluminescence could be triggered by reactive oxygen species, PECLM can measure relevant photocatalytic reactions, such as the oxygen reduction reaction. 41 Moreover, reactions which could produce nanobubbles on the nanocatalysts, such as hydrogen evolution reaction, could also be in situ imaged by PECLM through ECL blinking. 42 The proposed strategy shows promising potential in both fundamental studies of plasmon-induced hot carrier generation at nanoparticle interfaces and development of more efficient plasmonic nanocatalysts for photovoltaic and photocatalytic devices.…”

“…However, in addition to the model study, the PECLM could be used in real photocatalytic systems. For example, as luminol chemiluminescence could be triggered by reactive oxygen species, PECLM can measure relevant photocatalytic reactions, such as the oxygen reduction reaction . Moreover, reactions which could produce nanobubbles on the nanocatalysts, such as hydrogen evolution reaction, could also be in situ imaged by PECLM through ECL blinking .…”