Heterophase-Structured Cobalt Hydroxide on Partly Reduced Graphene Oxide for Enhanced Dopamine Biosensing

Abstract

A hetero-phase structure of cobalt hydroxide [α/β-Co(OH)2] in situ formed with the partly reduced graphene oxide [Co(OH)2/PRGO] has been fabricated by a coprecipitation method. Depending on the interactions (nucleation, bonding with oxygen-rich groups, and partial conversion of GO into rGO) provided by GO, cobalt ions utilized the interactions under alkaline conditions provided by 2-methylimidazole to form hetero-phase α/β-Co(OH)2 and maintain the unstable-structure [α-Co(OH)2]. Beneficial to the large electrochemical active surface, rich redox active sites, and electronic transfer capability derived from hetero-phase structure [α/β-Co(OH)2] and the partly reduced graphene oxide, the Co(OH)2/PRGO has an extraordinary detection performance of DA: a multi-section continuous detection range (0.1 nM to 450 μM), a ultra-low limit of detection (0.078 nM, S/N = 3), and a strong anti-interference ability, coupled with an application potential in biological foods (pork) and in the body environment (serum).