Two-dimensional metal-organic framework nanosheets: An efficient two-electron oxygen reduction reaction electrocatalyst for boosting cathodic luminol electrochemiluminescence

Exploration of electrocatalytic-luminol systems is still in the developmental stages because of the weak elec-trochemiluminescence (ECL) of cathodic luminol, and it is still a challenge to establish a conformational rela-tionship between electrocatalytic materials and ECL performance. Herein, functionalized two-dimensional NiZn metal-organic framework (MOF) nanosheets were synthesized using controlled heat treatment and were suc-cessfully applied to the two-electron (2e- ) oxygen reduction reaction (ORR) to produce H2O2. Interestingly, it was found that both the intermediates and products of the ORR significantly affected the ECL emission of luminol. It is worth noting that extending NiM MOF (M = Fe, Co, and Zn) to 2e- ORR reaction and achieving efficient luminol emission is undoubtedly beneficial for constructing cathodic luminol systems. This work demonstrates the relationship between the electrocatalytic materials and luminol ECL performance, thereby, broadening the applications of ECL reactions. Finally, the proposed biosensor was successfully used for the sensitive detection of alpha-fetoprotein (AFP).