Surface Engineering of Three-Dimensional-like Hybrid AB₂O₄ (AB = Zn, Co, and Mn) Wrapped on Sulfur-Doped Reduced Graphene Oxide: Investigation of the Role of an Electrocatalyst for Clioquinol Detection

Clioquinol (CQ) is a mass-produced drug with broad-spectrum antifungal and antibacterial properties. This neurodegenerative medicine has attracted significant attention in the pharmaceutical field. However, excessive administration of CQ presents neurotoxic effects that require its early detection and effective countermeasures. Electrochemical detection can be beneficial in this regard, using functional material architectures with multiple advanced features. A unique emphasis is placed on manipulating these hierarchical structures, for advanced functions, offering an impressive perspective for monitoring systems. In this paper, we report on the innovative synthesis of distinct structures of AB2O4 (AB = Zn, Co, and Mn) spinel metal oxide anchored sulfur-doped reduced graphene oxide (S-rGO) for the effective detection of CQ. Fascinatingly, unique flower-like manganese cobaltite (MCO) exhibits superior structural advantages over other spinels, and doping of S-rGO into the framework marks a significant improvement in electrochemical properties. The highly symmetrical floral architecture with straight edges and facets provides defect-rich active sites, and the dissolution of S-rGO facilitates faster electron transfer and improved surface area. A wide linear response range, low detection limit, excellent reproducibility, and stability show that this material offers an efficient electrocatalyst that reinforces the practical viability of S-rGO doped MCO spinel for analysis and monitoring of real samples. The unique structural characteristics of the synthesized electrocatalyst can further extend its functions and applications, thereby expanding its potential capabilities.