Electrocatalytic regulation of electrochemiluminescence: Mechanisms and sensing strategies

Electrocatalysis (EC) can reduce the overpotential and promote electrochemical reactions, leading to improved energy conversion, and electrochemiluminescence (ECL) is a convenient energy output. However, fundamental understanding of the relationship between EC and ECL performance has been very limited, hindering rational improvement and effective applications. Herein, as a proof of concept, we developed a model system composed of multi-walled carbon nanotubes (MWCNTs) as a catalyst, 6-aza-2-thiothymine protected gold nanoclusters (ATT-AuNCs) as luminophore, and tripropylamine (TPA) as coreactant, to evaluate the electrocatalytic effect on ECL by kinetic analysis of electrocatalytic reactions. A dual EC-mediated ECL enhancement was demonstrated in this system. The catalytically active sites were identified to be the carboxyl groups in the MWCNTs. We also discovered that EC could be tuned by other factors, such as wettability. Our findings were supported by density functional theory and molecular dynamics calculations as well. After understanding the EC mechanism, EC was then used to rationally regulate ECL for biosensor development for the first time. The detection of arginase with a record low limit of detection of 1.6 × 10−7 U mL−1 was achieved. This work not only enriches ECL regulation strategies, but also paves a new avenue for engineering EC guided ECL and devices.