ZIF-derived porous carbon loaded multicomponent heterostructured yolk@shell nanospheres as an ultrasensitive electrochemical sensing platform for the detection of caffeic acid in food

Multicomponent heterogeneous structures of yolk@shell nanospheres embedded in MOF-derived porous carbon are potentially excellent electrocatalytic materials. In this work, the multicomponent yolk@shell nanospheres (Au@Co 3 O 4 @CeO 2 ) were synthesized through an autocatalytic redox reaction. The synergistic and interfacial effects between Co 3 O 4 and CeO 2 can expose more active sites and enhance the catalytic activity. Then, the electrical conductivity of Au@Co 3 O 4 @CeO 2 was improved using N-doped carbon nanomaterials (NPC), which was derived from ZIF-8 by high-temperature pyrolysis. The synergistic catalytic effect between ZIF-8 derived NPC and Au@Co 3 O 4 @CeO 2 resulted in the highest electrochemical response current to caffeic acid in this composite. Under optimal conditions, the prepared modified electrode showed a LOD (limit of detection) of 5.7 × 10 −10 M for CA and a linear range of 1.0 × 10 −9 to 3.0 × 10 −6 M. Meanwhile, it showed remarkable selectivity for CA in the anti-interference experiments and can be applied to the detection in food samples (strawberry and red wine). This work has developed a novel sensing material for sensitive detection of CA, broadening the application of multi-component shell-core structured metal oxidation.